NASA/TP–2014–217522

International VLBI Service for

Geodesy and Astrometry 2013

Annual Report

Karen D. Baver (ed.)

NVI, Inc., Greenbelt, Maryland

Dirk Behrend (ed.)

NVI, Inc., Greenbelt, Maryland

Kyla L. Armstrong (ed.)

NVI, Inc., Greenbelt, Maryland

May 2014
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Preface

This volume of reports is the 2013 Annual Report

of the International VLBI Service for Geodesy and

Astrometry (IVS). The individual reports were contributed by VLBI groups in the international geodetic

and astrometric community who constitute the permanent components of IVS.

The IVS 2013 Annual Report documents the work

of the IVS components for the calendar year 2013,

our fifteenth year of existence. The reports describe

changes, activities, and progress of the IVS. Many

thanks to all IVS components who contributed to this

Annual Report.

With the exception of the first section and the last

section, the contents of this Annual Report also appear

on the IVS Web site at

http://ivscc.gsfc.nasa.gov

/publications/ar2013

This book and the Web site are organized as follows:

• The first section contains general information about

IVS, a map showing the locations of the components, information about the Directing Board members, and the annual report of the IVS Chair.

• The second section holds four special reports. The

first report, “Final Report of IVS Working Group

4 (WG4) on Data Structures”, presents the work of

Working Group 4, which was established in 2007

to design a data structure to meet requirements

for VLBI sessions and to prepare for the transition to the new structure. This report gives the

history of Working Group 4’s efforts, a description of the final data structure, and the remaining

steps neeeded to implement it. The second report,

IVS 2013 Annual Report

“IVS WG6 Final Report”, presents the work of

Working Group 6, which was established in 2009

to promote education and training within the IVS.

Working Group 6’s specific mandates were to develop contacts at educational institutions related to

VLBI in order to raise interest in VLBI among students, to develop educational material that could be

distributed to educational institutions, and to seek

funding, develop a concept, and prepare for providing training, e.g., through VLBI schools. The

WG6 report assesses how well WG6 has met its

mandates. The report lists contacts identified under

the first mandate, material collected under the second mandate, and funding efforts made under the

third mandate. The report concludes by discussing

and evaluating its first training school, which was

held in Helsinki, Finland in conjunction with the

EVGA meeting in March 2013, co-sponsored by

the European Geosciences Union (EGU), Onsala

Space Observatory, and RadioNet, and supported

by Aalto University and the Finnish Geodetic Institute. The third report, “VGOS Data Recorder Comparison”, presents tables that assess data recorders

for compliance with the VGOS (VLBI Global Observing System) standards. The fourth report, “Proposal for VGOS Observing Plan”, presents the plan

of the VPEG (VGOS Project Executive Group) to

gradually introduce VGOS observing over the next

several years. By means of trial sessions and pilot projects, the proposed observing plan transitions

from basically no VGOS observing in 2014 to a

fully established 24/7 VGOS observing program by

the end of the decade. The plan was endorsed by the

IVS Directing Board at its most recent meeting and

will be implemented by the IVS Coordinating Center and the OPC (Observing Program Committee).

iii
iv Preface

• The next seven sections hold the reports from the

Coordinators and the reports from the IVS Permanent Components: Network Stations, Operation

Centers, Correlators, Data Centers, Analysis Centers, and Technology Development Centers.

• The next section contains a compilation of publications in the field of geodetic and astrometric VLBI

during 2013.

• The last section includes reference information

about IVS. This year the information section

has been streamlined, and the majority of it will

only be provided on-line. This change conserves

paper, but it also recognizes that some categories

of information (most notably the list of Associate Members) change within a year, rendering

the printed information out-of-date. Therefore,

this year the information section only includes

the Terms of Reference and a table of links to the

Member and Affiliated organizations, the Associate

Members, and the permanent components.

As a replacement for the list of acronyms previously included in the Annual Report, the Coordinating Center plans to develop an on-line list of

acronyms to be posted on the IVS web site in the

future. The list of addresses of institutions that contributed to this year’s Annual Report has been discontinued.

IVS 2013 Annual Report
Table of Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

About IVS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

IVS Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

IVS Component Map . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

IVS Directing Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

IVS Chair’s Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Special Reports . . . . . . . . . . . . . . . . . . . . . . . 9

Final Report of IVS Working Group 4 (WG4) on Data

Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

IVS WG6 Final Report . . . . . . . . . . . . . . . . . . . . . . . . .26

VGOS Data Recorder Comparison . . . . . . . . . . . . . . 64

Proposal for VGOS Observing Plan . . . . . . . . . . . . . 70

IVS Coordination . . . . . . . . . . . . . . . . . . 81

Coordinating Center Report . . . . . . . . . . . . . . . . . . . . 83

The 2013 Analysis Coordinator Report . . . . . . . . . . 86

Network Coordinator Report . . . . . . . . . . . . . . . . . . . 89

IVS Technology Coordinator Report . . . . . . . . . . . . 95

Network Stations . . . . . . . . . . . . . . . . . . . 99

Badary Radio Astronomical Observatory 2013 IVS

Annual Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Effelsberg Radio Observatory 2013 Annual Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Fortaleza Station 2013 Annual Report . . . . . . . . . . 106

Goddard Geophysical and Astronomical Observatory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Hartebeesthoek Radio Astronomy Observatory (HartRAO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111

AuScope VLBI Project and Hobart 26-m Antenna 115

Kashima 34-m VLBI Station . . . . . . . . . . . . . . . . . . 119

Kokee Park Geophysical Observatory . . . . . . . . . . 123

IVS 2013 Annual Report

Kashima and Koganei 11-m VLBI Stations . . . . . 126

Matera CGS VLBI Station 2013 Annual Report . 130

Medicina Station Status Report . . . . . . . . . . . . . . . . 133

Metsahovi Radio Observatory Network Station 2013  ̈

Annual Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

VERA 2013 Geodetic Activities . . . . . . . . . . . . . . . 139

Noto Station Status Report . . . . . . . . . . . . . . . . . . . . 142

Ny-Alesund Geodetic Observatory 2013 Annual  ̊

Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

German Antarctic Receiving Station (GARS)

O’Higgins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Onsala Space Observatory – IVS Network Station

Activities During 2013 . . . . . . . . . . . . . . . . . . . . . . . . 151

Korea Geodetic VLBI Station, Sejong . . . . . . . . . . 155

Sheshan VLBI Station Report for 2013 . . . . . . . . . 158

The Simeiz Fundamental Geodynamics Area . . . . 160

Svetloe Radio Astronomical Observatory 2013 IVS

Annual Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

JARE Syowa Station 11-m Antenna, Antarctica . 167

Status of the TIGO VLBI Station in Concepcion .171  ́

Tsukuba 32-m VLBI Station . . . . . . . . . . . . . . . . . . .173

Nanshan VLBI Station Report 2013 . . . . . . . . . . . . 177

Warkworth Radio Astronomical Observatory, New

Zealand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

Westford Antenna 2013 Annual Report . . . . . . . . . 184

Geodetic Observatory Wettzell - 20-m Radio Telescope and Twin Telescopes . . . . . . . . . . . . . . . . . . . . 187

Instituto Geografico Nacional of Spain . . . . . . . . . 191  ́

Zelenchukskaya Radio Astronomical Observatory

2013 IVS Annual Report . . . . . . . . . . . . . . . . . . . . . . 195

Operation Centers . . . . . . . . . . . . . . . . . 199

The Bonn Geodetic VLBI Operation Center . . . . .201

CORE Operation Center 2013 Annual Report . . . 203

NEOS Operation Center . . . . . . . . . . . . . . . . . . . . . . 206

v
vi Table of Contents

Correlators . . . . . . . . . . . . . . . . . . . . . . . 207

The Bonn Astro/Geo Correlator . . . . . . . . . . . . . . . .209

Haystack Observatory VLBI Correlator . . . . . . . . .213

IAA Correlator Center 2013 Annual Report . . . . . 217

Correlation Processing in NICT Kashima . . . . . . . 221

Shanghai VLBI Correlator 2013 Annual Report . 224

Tsukuba VLBI Correlator . . . . . . . . . . . . . . . . . . . . . 227

Washington Correlator . . . . . . . . . . . . . . . . . . . . . . . . 231

Data Centers . . . . . . . . . . . . . . . . . . . . . . 233

BKG Data Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

CDDIS Data Center Summary for the IVS 2013

Annual Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

Italy INAF Data Center Report . . . . . . . . . . . . . . . . 240

Data Center at NICT . . . . . . . . . . . . . . . . . . . . . . . . . .241

Paris Observatory (OPAR) Data Center . . . . . . . . . 244

Analysis Centers . . . . . . . . . . . . . . . . . . 247

Analysis Center of Saint Petersburg University . . 249

Geoscience Australia Analysis Center 2013 Annual

Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

Report for 2013 from the Bordeaux IVS Analysis

Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .253

BKG/DGFI Combination Center Annual Report

2013 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257

Matera CGS VLBI Analysis Center . . . . . . . . . . . . 261

DGFI Analysis Center Annual Report 2013 . . . . . 263

GFZ Analysis Center 2013 Annual Report . . . . . . 265

The BKG/IGGB VLBI Analysis Center . . . . . . . . 268

GSFC VLBI Analysis Center Report . . . . . . . . . . . 272

Haystack Observatory Analysis Center . . . . . . . . . 276

IAA VLBI Analysis Center Report 2013 . . . . . . . . 280

Italy INAF Analysis Center . . . . . . . . . . . . . . . . . . . 283

JPL VLBI Analysis Center Report for 2013 . . . . . 285

KASI Combination Center 2013 Annual Report . 288

KTU-GEOD IVS Analysis Center Annual Report

2013 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292

Analysis Center at National Institute of Information

and Communications Technology . . . . . . . . . . . . . . 295

NMA Analysis Center 2013 Annual Report . . . . . 299

Paris Observatory (OPAR) Analysis Center . . . . . 301

Onsala Space Observatory – IVS Analysis Center

Activities during 2013 . . . . . . . . . . . . . . . . . . . . . . . . 304

PMD Analysis Center 2013 Annual Report . . . . . 308

Pulkovo IVS Analysis Center (PUL) 2013 Annual

Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312

SAI VLBI Analysis Center 2013 Annual Report . 316

SHAO Analysis Center 2013 Annual Report . . . . 318

Tsukuba VLBI Analysis Center . . . . . . . . . . . . . . . . 321

U.S. Naval Observatory VLBI Analysis Center . . 325

USNO Analysis Center for Source Structure Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

Vienna Special Analysis Center Annual Report

2013 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330

Technology Development Centers . . 335

Canadian VLBI Technology Development Center

Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337

GSFC Technology Development Center Report . .338

Haystack Observatory Technology Development

Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .341

NICT Technology Development Center 2013 Annual

Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345

Onsala Space Observatory – IVS Technology Development Center Activities during 2013 . . . . . . . . . . 349

Bibliography . . . . . . . . . . . . . . . . . . . . . . 353

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . 355

IVS Information . . . . . . . . . . . . . . . . . . . 367

IVS Terms of Reference . . . . . . . . . . . . . . . . . . . . . . 369

Links to Additional IVS Information . . . . . . . . . . . 376

IVS 2013 Annual Report
About IVS
2

IVS Organization

Objectives

IVS is an international collaboration of organizations which 

operate or support Very Long Baseline Interferometry 

(VLBI) components. The goals are:

1. To provide a service to support geodetic, geophysical 

and astrometric research and operational activities.

2. To promote research and development activities in 

all aspects of the geodetic and astrometric VLBI 

technique.

3. To interact with the community of users of VLBI 

products and to integrate VLBI into a global Earth 

observing system.

The IVS

• Interacts closely with the IERS, which is tasked by 

IAU and IUGG with maintaining the international 

celestial and terrestrial reference frames (ICRF

and ITRF),

• coordinates VLBI observing programs, 

• sets performance standards for the observing stations, 

• establishes conventions for data formats and products, 

• issues recommendations for analysis software,

• sets standards for analysis documentation,

• institutes appropriate product delivery methods in 

order to insure suitable product quality and timeliness.

Realization And Status Of IVS

IVS consists of

• 32 Network Stations, acquiring high performance 

VLBI data,

• 3 Operation Centers, coordinating the activities of a 

network of Network Stations,

• 7 Correlators, processing the acquired data, providing feedback to the stations and providing processed 

data to analysts,

• 5 Data Centers, distributing products to users, 

providing storage and archiving functions,

• 28 Analysis Centers, analyzing the data and producing 

the results and products,

• 6 Technology Development Centers, developing new 

VLBI technology,

• 1 Coordinating Center, coordinating daily and long 

term activities.

Altogether

• 82 Permanent Components, representing 43 institutions in 21 countries,

• ~280 Associate Members.

In addition the IVS has:

• Directing Board, determining policies, standards and 

goals; the board is composed of 16 members (elected 

and ex officio), including

• Coordinators for the network, analysis and technology.

ORGANIZATION OF INTERNATIONAL VLBI SERVICE
3

IVS Affiliated Organizations

The following organizations cooperate with IVS on issues 

of common interest, but do not support an IVS component. 

Affiliated Organizations express an interest in establishing 

and maintaining a strong working association with IVS to 

mutual benefit. Listed alphabetically by country. 

Products

The VLBI technique contributes uniquely to

• Definition and realization of the International Celestial 

Reference Frame (ICRF)

• Monitoring of Universal Time (UT1) and length of day 

(LOD)

• Monitoring the coordinates of the celestial pole (nutation and precession)

Further significant products are

• All components of Earth Orientation Parameters at 

regular intervals

• Station coordinates and velocity vectors for the realization and maintenance of the International Terrestrial 

Reference Frame (ITRF)

All VLBI data and results in appropriate formats are archived in data centers and publicly available for research 

in related areas of geodesy, geophysics and astrometry.

IVS Member Organizations

The following organizations contribute to IVS by supporting 

one or more IVS components. They are considered IVS 

Members. Listed alphabetically by country.

Organization Country

Geoscience Australia Australia

University of Tasmania Australia

CSIRO Australia

Vienna University of Technology Austria

Centro de Rádio Astronomia e Aplicações 

Espaciais

Brazil

Geodetic Survey Division, Natural 

Resources Canada

Canada

Dominion Radio Astrophysical 

Observatory

Canada

Universidad de Concepción Chile

Instituto Geográfico Militar Chile

Chinese Academy of Sciences China

Finnish Geodetic Institute, Aalto University Finland

Observatoire de Paris France

Laboratoire d’Astrophysique de Bordeaux France

Deutsches Geodätisches 

Forschungsinstitut

Germany

Bundesamt für Kartographie und Geodäsie Germany

Institut für Geodäsie und Geoinformation 

der Universität Bonn

Germany

Forschungseinrichtung Satellitengeodäsie, 

TU-Munich

Germany

Max-Planck-Institut für Radioastronomie Germany

GeoForschungsZentrum Potsdam Germany

Istituto di Radioastronomia INAF Italy

Agenzia Spaziale Italiana Italy

Politecnico di Milano DIIAR Italy

Geospatial Information Authority of Japan Japan

National Institute of Information and 

Communications Technology

Japan

National Astronomical Observatory of 

Japan

Japan

National Institute of Polar Research Japan

Auckland University of Technology New 

Zealand

Norwegian Mapping Authority Norway

Astronomical Institute of St.-Petersburg 

University

Russia

Institute of Applied Astronomy Russia

Pulkovo Observatory Russia

Sternberg Astronomical Institute of 

Moscow State University

Russia

Organization Country

Hartebeesthoek Radio Astronomy 

Observatory

South 

Africa

Korea Astronomy and Space Science 

Institute

South 

Korea

National Geographic Information Institute S. Korea

Instituto Geográfico Nacional Spain

Chalmers University of Technology Sweden

Karadeniz Technical University Turkey

Main Astronomical Observatory, 

National Academy of Sciences, Kiev

Ukraine

Laboratory of Radioastronomy of Crimean 

Astrophysical Observatory

Ukraine

NASA Goddard Space Flight Center USA

U. S. Naval Observatory USA

Jet Propulsion Laboratory USA

Organization Country

Australian National University Australia

University of New Brunswick Canada

FÖMI Satellite Geodetic Observatory Hungary

Joint Institute for VLBI in Europe (JIVE) Netherlands

Westerbork Observatory Netherlands

National Radio Astronomy Observatory USA
4

IVS Component Map

IVS Components by Country

Country Qty.

Australia 3

Austria 1

Brazil 1

Canada 1

Chile 1

China 4

Finland 1

France 3

Germany 10

Italy 7

Japan 12

New Zealand 1

Norway 2

Russia 9

South Africa 1

South Korea 2

Spain 1

Sweden 3

Turkey 1

Ukraine 2

USA 16

Total 82

Network Station

Former Station

Operation Center

Correlator

Data Center

Analysis Center

Technology Development Center

Coordinating Center

O’Higgins

TIGO

Fortaleza

Haystack

Canadian VLBI

Algonquin

Yellowknife

Gilmore Creek

JPL

Kokee Park

GGAO

NEOS

GSFC

USNO
5

GSI

NICT

Kashima 34

Kashima 11

Koganei

Katherine

Parkes

GA

Hobart

Warkworth

Yarragadee

Hartebeesthoek

Syowa

Mizusawa

Tsukuba

KASI

Shanghai

Seshan

Sejong

Nanshan

Badary

Zelenchukskaya

KTU

Simeiz

SAI

IAA

AIStPbU

Svetloe

NMA

GFZ

Metsähovi

Onsala

IGGB Effelsberg

Paris

FGS(BKG,IGGB)

Bordeaux

Wettzell

TU Vienna

Medicina

Matera

Noto PMD

Yebes

INAF

DGFI

PUL

BKG MAO

Ny Alesund
6

IVS Directing Board

NAME: Hayo Hase

AFFILIATION: Bundesamt für 

Kartographie und Geodäsie/

TIGO, Germany/Chile

POSITION: Networks 

Representative

TERM: Feb 2011 to Feb 2015

NAME: Rüdiger Haas

AFFILIATION: Chalmers 

University of Technology, 

Sweden

POSITION: Technology Development Centers Representative

TERM: Feb 2013 to Feb 2017

NAME: Dirk Behrend

AFFILIATION: NVI, Inc./Goddard 

Space Flight Center, USA

POSITION: Coordinating Center 

Director

TERM: ex officio

NAME: John Gipson

AFFILIATION: NVI, Inc./Goddard 

Space Flight Center, USA

POSITION: Analysis Coordinator

TERM: permanent

NAME: Patrick Charlot

AFFILIATION:Laboratoire 

d’Astrophysique de 

Bordeaux, France

POSITION: IAU Representative

TERM: ex officio

NAME: Alessandra Bertarini

AFFILIATION: University 

of Bonn, Germany

POSITION: Correlators

and Operation Centers

Representative

TERM: Feb 2011 to Feb 2015

NAME: Axel Nothnagel

AFFILIATION: University 

of Bonn, Germany

POSITION: Chair, Analysis and 

Data Centers Representative

TERM: Feb 2013 to Feb 2017

NAME: Ed Himwich

AFFILIATION: NVI, Inc./Goddard 

Space Flight Center, USA

POSITION: Network

Coordinator

TERM: permanent
7

NAME: Shinobu Kurihara

AFFILIATION: Geospatial 

Information Authority, Japan

POSITION: At Large Member

TERM: Feb 2013 to Feb 2015

NAME: Chopo Ma

AFFILIATION: NASA Goddard 

Space Flight Center, USA

POSITION: IERS Representative

TERM: ex officio

NAME: James Lovell

AFFILIATION: University of 

Tasmania, Australia

POSITION: Networks 

Representative

TERM: Feb 2013 to Feb 2017

NAME: Fengchun Shu

AFFILIATION: Shanghai 

Astronomical Observatory, 

China

POSITION: At Large Member

TERM: Feb 2013 to Feb 2015

NAME: Alexander Ipatov

AFFILIATION: Institute of 

Applied Astronomy, Russia

POSITION: At Large Member

TERM: Feb 2013 to Feb 2015

NAME: Arthur Niell

AFFILIATION: MIT Haystack 

Observatory, USA

POSITION: Analysis and Data 

Centers Representative

TERM: Feb 2013 to Feb 2015

NAME: William Petrachenko

AFFILIATION: Natural 

Resources Canada, Canada

POSITION: Technology

Coordinator

TERM: permanent

NAME: Harald Schuh

AFFILIATION: GFZ German 

Research Center for 

Geosciences, Germany

POSITION: IAG Representative

TERM: ex officio
8

IVS Chair’s Report

Axel Nothnagel

Institut für Geodäsie und Geoinformation der Universität 

Bonn

On March 8, 2013 at the 29th IVS Directing Board Meeting, I was elected the third chair of the IVS following my 

successful predecessors, Wolfgang Schlüter and Harald 

Schuh. In the last six years, Harald has done a tremendous job, pushing the IVS forward in our initiative which 

is now called VGOS, the VLBI Global Observing System. 

I should state that Harald’s name will always be linked 

directly to the VGOS acronym.

For my own person, I am proud to be chairing the IVS 

with its many motivated and active individuals, as I indicated at various occasions already. I hope that I will be 

a chair who fulfills most if not all expectations which the 

community puts onto me.

Since my election, only a few but still noteworthy activities fell into my responsibility. Most of them are rather of 

administrative nature which also have to do with seeking 

approval of the directing board. The most important one 

certainly is that the VGOS Observing Plan was adopted 

and is now available on the IVS web site for reference. 

The VGOS Observing Plan should guide us during the 

transition period from legacy to VGOS operations which 

is purely based on wide-band observations.

Another highlight in 2013 was the approval of the South 

African Government to fund the construction of a fully 

equipped VGOS telescope at the Hartebeesthoek Radio Astronomy Observatory near Johannesburg, South 

Africa. We are really looking forward to this new contributor which will be fundamental to VGOS in the southern 

hemisphere. Independently of this, the Directing Board 

also voted unanimously for holding the 9th IVS General 

Meeting scheduled for 2016 in South Africa.

In my function as the IVS Chair I attended the IERS Local Tie Workshop in Paris, France, on May 21/22, 2013, 

and presented the IVS status and prospects at the IAG 

Scientific Assembly in Potsdam, Germany, on September 

4, 2013.

All in all, I can state that I have taken over a well functioning entity from my predecessor, Harald Schuh, where 

there is little to no necessity for fundamental changes. 

Our way of developing the IVS further by the establishment of VGOS is certainly something which will need our 

full attention in the next few years. However, we should 

not forget that there is ample scope of application also 

for the legacy antennas with the current setup of S/X 

band observations in the future. We should try to keep 

and operate them as long as possible. In between the two 

standard configurations, there may be a need for mixedmode operations to link the VGOS telescopes into the 

VLBI terrestrial reference frame. All of this requires strong 

endeavors of research and development. At the same time, 

however, let us always remember that we are a service 

which serves quite a number of customers and that the 

majority of activities has to follow the concept of a service.

In this respect, I thank already all contributors to this annual report and our colleagues at the IVS Coordinating 

Center for compiling, printing and distributing this issue. 

The timely appearance and distribution of the annual report has always been a trademark of the IVS.
Special Reports

11

Final Report of IVS Working Group 4 (WG4)

on Data Structures

John Gipson1, Johannes Böhm2, Sergei Bolotin1, David Gordon1, Thomas Hobiger3, Chris Jacobs4

, Sergey Kurdobov5, Axel Nothnagel6, Ojars Sovers7, Oleg Titov8, Hiroshi Takiguchi9

1NVI, Inc at NASA Goddard Spaceflight Center, United States,

2Department of Geodesy and Geoinformation, Vienna University of Technology, Austria

3

National Institute of Information and Communications Technology, Japan 

4

Jet Propulsion Laboratory, United States

5

Institute of Applied Astronomy, St. Petersburg, Russia

6

Institute of Geodesy and Geoinformation, University of Bonn, Germany

7Remote Sensing Analysis, Inc., United States

8Geosciences Australia, Australia

9

Auckland University of Technology, New Zealand

1 History

At the 15 September 2007 IVS Directing Board meeting I proposed establishing a “Working

Group on VLBI Data Structures”. The thrust of the presentation was that, although the VLBI database system has served us very well these last 30 years, it is time for a new data structure that 

is more modern, flexible, and extensible. This proposal was unanimously accepted, and the board 

established IVS Working Group 4. Quoting from the IVS Web site [1]: 

“The Working Group will examine the data structure currently used in VLBI data processing 

and investigate what data structure is likely to be needed in the future. It will design a data 

structure that meets current and anticipated requirements for individual VLBI sessions including 

a cataloging, archiving, and distribution system. Further, it will prepare the transition capability 

through conversion of the current data structure as well as cataloging and archiving softwares 

to the new system.”

2 Organization of the Working Group

Any change to the VLBI data format affects everyone in the VLBI community. Therefore, it is 

important that the working group have representatives from a broad cross-section of the IVS 

community. The initial membership was arrived at in consultation with the IVS Directing Board. 

Table 1 lists the current and past members of WG4 together with the

Table 1. Past and Current Members of IVS Working Group 4

John Gipson Chair/Solve

Sergei Bolotin Steelbreeze

Roger Capallo Correlators

Axel Nothnagel Analysis Coordinator
12

We were all saddened at the premature death of Anne-Marie Gontier during this period. In addition some members left the Working group because of a change in professional status or retirement. 

3 Earlier Related Work

There have been proposals to redesign how geodetic VLBI data is stored and archived. We want 

to particularly mention two of these. We want to particularly mention:

1. A memo written by Leonid Petrov “Specifications of a geo-VLBI format” in the late 

1990s. [See reference to undated memo by L. Petrov in Reference.]

2. The work of Anne-Marie Gontier on the Gloria database.

In addition, at the second IVS Analysis Workshop in February 2001, a working group was set up 

to develop a VLBI exchange format independent of platforms and operating systems. This working group included Gontier and Petrov, as well as other members of the VLBI community. The 

working group resulted in the definition of the PIVEX format [Gontier, 2002]. Several Mark3 

databases, including an Intensive (01DEC31XU), a NEOS (01DEC11XE) and an RDV session 

(01MAY09XA) were converted to PIVEX format. Unfortunately, PIVEX was never widely 

adopted in the VLBI community. 

Since the goals of this earlier working group were substantially similar to IVS Working Group 4 

It is not surprising that WG4 was strongly influenced by this earlier work since the goals of this 

earlier working group were so similar. We learned from both the successes and failures of this 

earlier work. In terms of success much of the way the data is organized is similar to the organization proposed by Petrov and/or Gontier. In particular, organizing data by scope (how broadly applicable is the data) and the concept of wrapper are very similar to L. Petrov. Both of these are 

discussed below. A major difference is that WG4 proposes relying on an established format 

(NetCDF) to store the VLBI data instead of defining an entirely new format. 

4 History and Goals

WG4 held its first meeting at the 2008 IVS General Meeting in St. Petersburg, Russsia. This

meeting was open to the general IVS community. Roughly 25 scientists attended: ten WG4

members and fifteen others. This meeting was held after a long day of proceedings. The number

David Gordon Calc/Solve

Chris Jacobs

Ojars Sovers

Modest

Oleg Titov

Volker Tesmer

Occam

Johannes Böhm Vievs

Sergey Kurdobov IAA 

Anne-Marie Gontier PIVEX

Thomas Hobiger

Hiroshi Takiguchi 

NICT/C5++
13

of participants and the lively discussion that ensued is strong evidence of the interest in this subject.

A set of design goals, displayed in Table 1, emerged from this discussion. In some sense the design goals imply a combination and extension of the current VLBI databases, the information 

contained on the IVS session Web-pages, and much more information [2].

During the next year the working group communicated via email and telecon and discussed how 

to meet the goals that emerged from the St. Petersburg meeting. A consensus began to emerge

about how to achieve most of these goals.

Table 1. Design Goals of Working Group IV

Goal Description

Provenance Users should be able to determine the origin of the data and what was 

done to it.

Compactness The data structure should minimize redundancy and the storage format 

should emphasize compactness.

Speed Data retrieval should be fsat. 

Platform/OS/

Language Support

Data should be accessible by programs written in different languages, 

running on a variety of computers and operating systems.

Extensible It should be easy to add new data types.

Open Data should be accessible without the need of proprietary software.

Decoupled Different types of data should be separate from each other.

Multiple data levels Data should be available at different levels of abstraction. For example, 

levels most users are only interested in the delay and rate observables. 

Specialists may be interested in correlator output.

Completeness All VLBI data required to process (and understand) a VLBI session 

from start to finish should be available: schedule files, email, log-files, 

correlator output, and final ‘database’.

Web Accessible All data should be available via the Web.

The next face-to-face meeting of WG4 was held at the 2009 European VLBI Meeting in Bordeaux, France. This meeting was also open to the IVS community. At this meeting a proposal 

was put forward to split the data contained in the current Mark3 databases into smaller files 

which are organized by a special ASCII file called a wrapper. Overall the reaction was positive.

In the summer of 2009 we worked on elaborating these ideas, and in July a draft proposal was 

circulated to Working Group 4 members. The ideas continued to be refined over the next years. 

Because of the desire for the new format to be open, and as a nod to Mark3 database structure, 

we originally called the new format openDB. A subsequent internet search revealed that this 

name was already taken, and the new format was renamed to vgosDB. 
14

5 Current Organization of VLBI Data

Currently the smallest piece of VLBI data that is routinely analyzed is a VLBI session. This information is archived and stored in Mark3 database. These databases contain information used in 

the analysis of a VLBI session, which are usually 1-hour (intensives) or 24-hours. With very few 

exceptions, there are usually gaps between sessions, and hence a VLBI session is a natural piece 

of VLBI data to work with. 

5.1 Mark3 Databases

The Mark3 database organizes data by “Lcodes” with each Lcode corresponding to a different 

data item. The data associated with a given Lcode can be stored as ASCII Strings, Integer*2, Integer*4 or Real*8. The Mark3 database was designed to contain all1

the data necessary to analyze a VLBI session within a single file. The database file contains the observables but it also 

contains theoretical values, partials and calibrations.

There are two types of Lcodes:

1. Type-1 Lcodes contain data that is applicable for the entire session. 

a. Examples: station names and positions, source names and positions, session 

name, etc. 

b. This information occurs only once in the database. 

c. There are roughly 100 different Lcodes. 

2. Type-2 and -3 Lcodes are conceptually identical. Type-3 Lcodes were introduced because 

of limitations of the HP operating system in the 1980s. These Lcodes contain observation 

dependent data:

a. Examples: EOP data, a priori nutation, various partials, delay, rate, sigmas. 

b. The database contains data for each Lcode and each observation, e.g., each observation has an associated EOP value, met values, etc.

c. There are around 400 different Type-2 and Type-3 Lcodes. 

The Mark3 databases are fundamentally organized by observation, as illustrated below.

Table 2. Mark3 databases are organized by session- and observation-dependent data. 

Type 1 Lcodes: Session Data

Source List Station List Correlator Principle InvestigatorFlags Etc...

Type 2 and 3 Lcodes: Observation Data

Lcode1

SourceName

Lcode2

1

st Station

Lcode3

2

nd Station

Lcode3

EOP

... LcodeM

Observable

Obs1

Obs2

...

ObsN

 

1 Over time this proved impractical, and some of data is now stored in external files. Examples include EOP files, 

pressure loading, episodic motion, etc. 
15

It is important to note that the Mark3 database format is both a method of organizing data and a 

means of storing data. Data is organized by Lcodes, where the Lcodes are Session-dependent or 

Observation dependent. The data is stored in a proprietary format. 

The Mark3 database format has some nice features which we do not want to lose. Among these 

are:

1. Table of Contents. You can easily see what data is available in a given database. 

2. Self-descriptive data. Each data item has a brief description of what it is.

3. History. Each database contains a history of its processing.

The specific Lcodes within a database vary depending on the age of the database and how the 

data was processed. Older databases contain obsolete Lcodes which are relics of how the data 

was analyzed at the time. In addition databases contain information about the fringing process, 

and this information is different for each kind of correlator. The number of Lcodes has increased 

over time as a result of model changes, the desire to use new kinds of data, etc. A consequence of 

this is that a Mark3 database contains data that is obsolete and never used. 

Some problems associated with Mark3 databases are:

1. Requires proprietary software.

2. Only used by the calc/solve user community. 

3. Redundancy. 

a. Much VLBI data is really scan-dependent, not observation dependent.

b. There is one database for each band.

4. Mixing of observations and theoretical models.

5. Changing a model or adding new kinds of data means updating the entire database.

6. Difficult or impossible to exchange partial information, i.e., ambiguity resolution or editing criteria.

7. Contains obsolete data and models.

8. Contains data that is very seldom used.

9. Contains data that is calc/solve specific.

10. Slow data access which makes it prohibitively time-consuming to use the Mark3 database 

in large VLBI solutions.

In spite of the above problems, the Mark3 database has been in use for over 35 years which is a 

testament to the many virtues it has. 

5.2 NGS Card Format

Because of the proprietary nature of the Mark3 database an alternative format called "NGS card" 

format was developed to exchange VLBI information. This consists of a single ASCII file with a 

series of lines. The top of the file contains header information which describes the session as a 

whole, such as stations, sources and their positions. This is analogous to the Type-1 Lcodes in 

the Mark3 database. This is followed by information about the observations. This is analogous to 

the information contained in the Type-2 Lcodes.

The advantage of the NGS format is that it is fairly easy to write software to parse the file. Some 

of the disadvantages are:
16

1. Inflexible. Hard to add new data types.

2. Does not contain all of the VLBI data needed to analyze a solution from the beginning. 

Hence errors in the initial data editing and ambiguity resolution are 'baked-into’ the data 

and become impossible to fix down-stream. 

3. Machine access is slower than for binary files.

5.3 PIVEX Format

Pivex was an ASCII format designed to archive and store VLBI data [Gontier 2002]. It was never widely adopted. 

5.4 Other Formats

Because of the speed advantages that storing data in binary files has, most VLBI analysis software uses a custom format specific to the particular software.

For doing large global solutions which combine data from many sessions, solve stores data in 

'superfiles'. These superfiles are essentially binary dumps of Fortran common blocks which contain subsets of the data in a Mark3 database. The organization is also roughly similar to that of 

Mark3 databases. One common block contains information common to the session as a whole. 

Another common block contains information applicable to a given observation. Solve uses this 

information by reading in the common-block for a particular observation en-masse. 

Other software packages such as Steelbreeze, Occam and VieVs use their own proprietary format. This makes it difficult to exchange data.

As mentioned above, one of the primary reasons for using a proprietary format is that Mark3 database access is slow. Proprietary binary formats were developed in part as a reaction to this. On 

the other hand the NetCDF format is designed for fast access. One of the goals of the vgosDB is 

to encourage the use of a common format for data processing and exchange. 
17

6 Overview of vgosDB format

In this section we present a brief overview of the new format. 

6.1 Organizing Data by Sessions

The smallest piece of VLBI data routinely analyzed is the data contained in a Mark3 database.

Each database contains the data for a single session. Sessions are usually 24 hours (standard sessions) or 1 hour (intensives). With a few exceptions such as the CONT series (campaigns where 

VLBI data is taken over an extended period of time, usually around 2 weeks), there are usually 

gaps between sessions, and hence a VLBI session is natural piece of VLBI data to work with. 

In the most optimistic VLBI2010 scenario, there are never gaps in the observing. Some stations 

may stop observing for a time (for example, for scheduled maintenance), but there will always be 

a number of stations observing. This is analogous to the situation in GPS and SLR, where some 

instruments are always on. However, both of these techniques find it useful to divide data into 

smaller pieces for analysis. 

A crucial difference between VLBI and the other space-geodetic techniques is that VLBI is a cooperative venture—stations must observe in a coordinated manner, i.e., two or more stations 

must observe the same source at the same time, and the observing modes must be the same or 

similar. If the observing mode is substantially different, then you cannot correlate the data between two stations, and hence there are no observables. 

We propose to continue to organize data by session. However, instead of storing most of the data 

related to a particular session in a Mark3 database, the vgosDB format breaks the data into 

smaller pieces which are stored in files (see below). All of the data associated with a particular 

session is stored under a directory named after that session, e.g., 10JAN04XA would contain all 

of the information related to IVS session R1412. 

6.2 Modularization

A solution to many of the design goals of Table 3 is to modularize the data, that is to break up

the data associated with a session into smaller pieces. These smaller pieces are organized by 

‘type’; e.g., group delay observable, pressure data, temperature data, editing criteria, station 

names, and station positions. In many, though not all, cases, each ‘type’ corresponds to a Mark3

database Lcode. We refer to each data item as an vgosDB variable. 

Different data types are stored in different files, with generally only one or a few closely related 

data types in each file. For example, it is logical to store all of the met-data for a station together

in a single file. This data usually comes from a single instrument. However, there is no compelling reason to store the met-data together with pointing information. Splitting the data in this way 

has numerous advantages, some of which are outlined below. The first three directly address the 

design goals. The last was not originally specified, but is a consequence of this design decision.

1. Separable. Users can retrieve only that part of the data in which they are interested.
18

2. Extensible. As new data types become used, for example, source maps, they can be easily

added without having to rewrite the whole scheme. All you need to do is specify a new 

data type and the file format.

3. Decoupled. Different kinds of data are separated from each other. Observables are separated from models. Data that won’t change is separated from data that might change.

4. Partial Data Update. Instead of updating the entire database, as is currently done, you only need to update that part of the data that has changed.

6.2.1 Reducing Redundancy.

Data will also be organized by ‘scope’, that is how broadly applicable it is: A) The entire session 

(for example, source position); B) A particular scan (EOP); C) A particular scan and station

(met-data); D) or for a particular observation (delay observable and sigma). The current Mark3

database is observation oriented: all data required to process a given observation is stored once 

for each observation. This results in tremendous redundancy for some data. For example, in an 

N-station scan, there are N*(N-1)/2 observations, and each station participates in N −1 observations. Scan dependent data, such as EOP or source information, is the same for all observations 

in a scan. However in Mark3 databases, this information is stored once for each observation, resulting in an N*(N-1)/2 times redundancy. Station dependent data which is the same for all observations in a scan, such as pointing or met-data, is stored N-1 once for each observation the 

station participates in the scan, resulting in an (N − 1)-fold redundancy. Organizing data by 

scope allows you to reduce redundancy.

6.3 NetCDF as Default Storage Format 

Working Group 4 reviewed a variety of data storage formats including NetCDF, HCDF, CDF, 

and FITS. In some sense, all of these formats are equivalent—there exist utilities to convert from 

one format to another. Ultimately we decided to use NetCDF, because it has a large user community since numerical weather models are stored in NetCDF files. Several members of the 

Working Group have experience using NetCDF. In addition, Thomas Hobiger [Hobiger 2008]

wrote a program to store Mark3 databases in NetCDF format and developed analysis software 

that uses the NetCDF format [Hobiger 2010].

At its most abstract, NetCDF is a means of storing arrays in files. The arrays can be of different 

sizes and shapes, and contain different kinds of data—strings, integer, real, double, etc. Most 

VLBI data used in analysis is some kind of array. From this point of view using NetCDF is a 

natural choice. These files can contain history entries which aid in provenance. Storing data in 

NetCDF format has the following advantages:

1. Platform/OS/Language Support. NetCDF has interface libraries to all commonly used 

computer languages running on a variety of platforms and operating systems.

2. Speed. NetCDF is designed to access data fast.

3. Compactness. The data is stored in binary format, and the overhead is low. A NetCDF 

file is much smaller than an ASCII file storing the same information.

4. Open. NetCDF is an open standard, and software to read/write NetCDF files is freely 

available.
19

5. Transportability. NetCDF files use the same internal format regardless of the machine architecture. Access to the files is transparent. For example, the interface libraries take care 

of automatically converting from big-endian to little-endian.

6. Large User Community. Because of the large user community, there are many tools developed to work with NetCDF files. 

Figure 1. A NetCDF file is a container to hold arrays. 

6.3.1 NetCDF Attributes. 

Another feature of NetCDF is the ability to easily store meta-data related to a variable. This meta 

data is called an ‘attribute’ arbitrary, and can be used to store information such as: 

1. Units

2. Definition

3. Creation date of data.

4. Corresponding LCODE name if any. 

5. Any other used-specified characteristic.

6.4 Organizing Data Within a Session Using Wrappers 

In contrast to the current Mark3 databases where all (actually most) of the data required to analyze a data is one file, the new scheme proposes dividing the data up into smaller pieces. This 

allows updating the individual pieces separately and gives great flexibility in what is used. Because we split the data into smaller pieces, there must be another means of organizing the data. 

Wrappers solve this problem.

1. A wrapper is an ASCII file which contains 

a. Information about the session

b. Pointers to files which contain the actual data

Array1

M1xN1xO1

Integer*2

Array2

M2xN2

Real*8

Array3

M3xN3

Character

Array4

M4xN4

Real*4

Array5

M5xN5

Real*8
20

2. A wrapper file is distinguished by the extension “.wrp”. 

3. Wrappers are never over written. Instead, as the results of analysis, or as needs change, a 

new wrapper is created. 

openDB Format

Schedule 

Info

Observables 

Editing

Etc

Mapping 

functions

Wrapper

Met Data

Partials O-C . 

The wrapper is an ASCII file that contains pointers to other files 

in netCDF format that contain the data. 

Typically each of these other files contain a ‘few’ data items 

corresponding to different Lcodes. 

Wrappers have many advantages, a few of which are mentioned below.

1. Ability to easily test different models by pointing to different netCDF files.

2. Ability to only update that part of the data which has changed.

3. Ability to try different editing criteria. 

6.5 VgosDB Manual

The above is mentioned as an overview of the vgosDB format. It is not meant to completely 

define the format—instead it is meant to give the flavor of the format. A preliminary manual is 

avialable via anonymous ftp from: 

ftp::/gemini.gsfc.nasa.gov/pub/misc/jmg/vgosDBv_v2013Jun11.pdf

The final version of the manual will be put on the IVS website when it is completed. 
21

7 Feasibility Demonstrations

In August of 2009 John Gipson began a partial implementation of these ideas and wrote software 

to convert a subset of the data in a Mark3 database into the new format. This subset of data included all of the data available in NGS card format. The subset was chosen because many VLBI 

analysis packages including Occam, Steelbreeze, and VieVS use NGS cards as input. The GSFC 

VLBI group made available via anonymous FTP an Intensive, an R1 and a RDV session.

In the fall of 2010, Andrea Pany of the Technical University of Vienna developed an interface to 

VieVS working with the draft proposal. During this process the definition of a few of the data

items needed to be clarified, which emphasizes the importance of working with the data hands

on. With these changes VieVs was able to process data in the new format without problem. 

At roughly the same time at NASA’s Goddard Spaceflight center, Sergei Bolotin interfaced a 

variant of this format to Steelbreeze. Steelbreeze uses its own proprietary format, and one motivation for interfacing to the new format was to see if there was a performance penalty associated 

with using the new format. Bolotin found a small performance penalty of 40μs/ observation. Processing all 7 million then-available VLBI observations would result in a total performance penalty of 280 seconds, or 6 minutes 40 seconds. This seemed to be a relative modest price to pay for 

the many advantages of this format. 

In late 2010 and early 2011 Gipson modified the VLBI analysis program solve to use a subset of 

the data stored in vgosDB format. This subset contained some observation dependent data such 

as the delay observable and pointing information. The remaining data was extracted from the 

solve-superfiles. (A superfile is a binary file containing a sub-set of all the data in the Mark3 database that is used in global solutions. Superfiles lack the flexibility of Mark3 databases, but data 

access is much faster.) This test had two distinct purposes. First, it was a demonstration of the 

feasibility of using netCDF files to store VLBI data. Second, it was a required first step in the 

conversion of solve to use the new format. 

8 Conversion of Mark3 Database to VgosDB format

In 2011 and 2012 Gipson worked on a utility db2openDB to convert all of the data in all of 

Mark3 databases into the openDB format. As mentioned above, this format was subsequently 

renamed to vgosDB. (A modified version of this program called db2vgosDB is available as part 

of the calc/solve distribution.) As there approximately 500 different Lcodes this process took 

longer than anticipated. In addition many of the Mark3 databases, especially the older ones, had 

problems that needed to be fixed. A partial listing of some of the problems follows:

1. All of the Mark3 databases have an LCODE ‘NUM OBS’ that is supposed give the total 

number of observations in the database. However, several of the older databases actually 

had fewer observations than indicated, while a few had more. 

2. Many of the Mark3 databases had duplicated data. There were two different Lcodes (a 

type-2 and a type-3 lcode) containing exactly the same data. In these cases the duplicate 

data was removed.
22

3. Many databases had bad or incorrect values for some of the data items. Each case had to 

be examined to determine how to handle the situation. In some cases the missing data 

could be inferred from data that was present in the database. In other cases the observation had to be flagged as bad.

In the spring of 2012 the conversion was essentially complete. All of the existing Mark3 databases were converted to openDB format and the results made accessible via anonymous ftp at: 

ftp:://gemini.gsfc.nasa.gov/pub/openDB. 

8.1 Conversion of Calc/Solve to Use vgosDB Format

Historically the default storage format for geodetic VLBI sessions is Mark3 databases. This is 

the data format that the VLBI data is archived in, and the format that many IVS analysis centers 

use to process and store their results in. Other formats, such as NGS cards, or the custom format 

used by other analysis packages are all derived either directly or indirectly from the Mark3 databases. The software that produces edited and fully resolved Mark3 databases is the Calc/Solve

analysis suite. Because of this, as part of the transition to the vgosDB format it is necessary to 

modify Calc/Solve to use the new format.

Figure 3 on the following pages lists the necessary processing steps before VLBI data is ready 

for use. We give a brief summary of each of the steps below. Depending on the VLBI analysis 

package the names of the programs involved may differ, but the steps remain the same. 

1. The correlator takes the recorded data from the stations and produces correlator output 

files.

2. dbedit reads the correlator files, extracts the relevant information, and produces an initial 

Mark3 database. It actually produces both an X-band and S-band database.

3. Calc adds additional information to the X-band database. Some of this information, such 

as pointing information, is used by all analysis packages. Other information is specific to 

the solve.

4. Cable-cal and met-data is added to the X-band database by dbcal. The order of steps two 

and three can be reversed.

5. The data is read into solve. An analyst performs an initial solution where they resolve 

ambiguities and edit the data. The X-band database is written out and now includes a subset of the S-band data.

At this stage the Mark3 database is ready to be used in geodetic analysis. Many analysis packages use NGS-card format as input. (NGS cards contain a subset of the data in the Mark3 database

in an ASCII file). Most analysis software, including calc/solve, convert the data into a proprietary binary format before using it. In the case of calc/solve this format is called ‘superfiles.

In converting to the vgosDB format we need to develop software that reproduces all of the above 

steps. Since the Goddard VLBI group is the group that maintains calc/solve, this work was undertaken at Goddard.
23

Figure 2. VLBI processing steps. 
24

The approach was to start at the end of the processing chain and work backwards. The first step 

was to modify the globl mode of solve to use the vgosDB format instead of superfiles. The utility 

db2vgosDB read in edited and fully resolved Mark3 databases and produced vgosDB format sessions. Conversion of globl to use vgosDB sessions was completed in the summer of 2012. Timing tests showed that smaller sessions such as intensives run somewhat slower using the vgosDB

format. In contrast larger sessions such as the RDV sessions or CONT11 sessions run up to 40% 

faster. A solution using all of the VLBI runs slightly faster using the vgosDB format.

The remaining programs displayed on the right-hand-side of Figure 2 were developed at Goddard during late 2012 and early 2013. Several sessions including an R1s, RDVs and intensives 

were processed completely, starting from correlator output and ending in fully resolved vgosDB

sessions. The results were consistent with or identical with the normal processing using Mark3 

databases. (In the process of developing this software the Goddard VLBI group found and fixed 

some bugs in the normal processing chain.)

The process of developing the processing software was very useful and lead to some refinements 

in the vgosDB specification. One example of this involves changing which NetCDF files contain 

some particular data items. For example, in the first implementation of the vgosDB format, both 

the Names and Positions of stations were stored in the file ‘Head.nc’ which contains general information about the session. This worked satisfactorily when we were starting with a version 4 a 

fully resolved Mark3 database which contains all of this information. However if we are creating 

the vgosDB session by scratch the station position information is not available until after the data 

has been calc-ed. Because of this it is logical to remove the station position (and source position) 

information from Head.nc and store it separately. Other examples include renaming vgosDB variables and filenames to make them more consistent. 

9 Next Steps 

In this section we describe next steps in the implementation and decimation of the vgosDB format to the IVS community. 

The ‘development’ version of the Calc/Solve analysis suite at Goddard has the ability to use either superfiles or vgosDB files in global solutions. In addition, υSolve, the replacement for interactive solve, can read and write vgosDB files. These capabilities will be made widely available 

with the next general release of Calc/Solve scheduled for fall 2013.

Beginning in 2014, the Goddard VLBI group will take on responsibility for producing vgosDB

versions of all VLBI sessions available to IVS. This includes sessions for which Goddard has 

primary responsibility (e.g., R1s and RDVs) and also sessions for which other analysis centers 

have primary responsibility. This will be done by using the utility db2vgosDB to convert fully 

edited and resolved Mark3 databases to vgosDB format. As the year progresses and as other 

Calc/Solve analysis centers (which are responsible for producing the Mark3 databases) get familiar with the handling and producing vgosDB sessions Goddard will reduce the number of 

vgosDB sessions it produces. For at least 1-year both Mark3 databases and vgosDB sessions will 

be available on the IVS website. 
25

The VLBI analysis software suite VieVs, developed at the Technical University of Vienna, can 

use vgosDB sessions in its analysis. This capability will be maintained and enhanced as time 

permits. For example, currently VieVs must start with a fully resolved Mark3 database. As time 

permits this capability will be added to VieVs and it will use the vgosDB format to store the related information.

It is hoped that other software packages such as Occam, C5++ are modified to read and write 

vgosDB format. This will allow the easy exchange of information among these software packages. 

10 References

1. Petrov, L. “Specifications of a proposed geo-VLBI dataformat”, 

http://gemini.gsfc.nasa.gov/development/gvf/gvf.html. Undated memo

2. Abdekar, K., Gontier, A-M, “The Gloria VLBI tables”, http:

3. Gontier, A-M. and Feissel, M., “PIVEX: a Proposal for a Platform Independent VLBI 

Exchange Format”, The 2nd IVS General Meeting Proceedings, 2002 p. 248-254.

4. Gipson, J., “IVS Working Group 4 on VLBI Data Structures”, The 5th IVS General Meeting Proceedings, 2008 p. 143-152

5. Hobiger, et al, “MK3TOOLS – Seamless Interfaces for the Creation of VLBI Databases 

from Post-Correlation Output”, The 5th IVS General Meeting Proceedings, 2008 p. 143-

153-156.

6. Gipson, J., “IVS Working Group 4 on VLBI Data Structures”, The 6th IVS General Meeting Proceedings, 2010 p. 187-191

7. Hobiger, et al., “C5++ - Multi-technique Analysis Software for Next Generation Geodetic Instruments”, The 6th IVS General Meeting Proceedings, 2010 p. 212-216.

8. Gipson, J., Report on IVS-WG4, 20th EVGA Meeting, p 142-146. 

9. Gipson, J., IVS Working Group 4 on VLBI Data Structures, The 7th IVS General Meeting 

Proceedings, 2012 p. 212-221.

10. Gipson, J. IVS Working Group 4 on VLBI Data Structures, 

11. Draft openDB Manual version 2013Jun11:

ftp::/gemini.gsfc.nasa.gov/pub/misc/jmg/openDBv_v2013Jun11.pdf
26

IVS WG 6

Final report

Rüdiger Haas

September 2013

Introduction

The IVS Directing Board established on its meeting in March 2009 in Bordeaux a working 

group on Education and Training. This working group is IVS WG6 and its work was to be

reviewed regularly by the IVS DB at its meeting. The general aim of IVS WG6 is to support 

education and training in the field of geodetic and astrometric VLBI, in order to hand over 

and maintain expertise in this field for the next generations.

The Terms of Reference (ToR) of IVS WG6 were:

to establish contacts to education institutions in geodesy, geosciences and astrometry worldwide 

with the aim to raise interest in geodetic and astrometric VLBI among students

to develop education material that can be distributed to education institutions

to seek funding and to develop a concept and prepare the organization of training in form of for 

example IVS summer schools for master and PhD students

The WG was chaired by Rüdiger Haas: other initial members were Oleg Titov, Hayo Hase, Bjørn 

Engen, Johannes Böhm, Dirk Behrend, and Alan Whitney. Further candidate members were to be 

asked later to support the group.
27

ToR-1

The task was to establish contacts to education institutions in geodesy, geosciences and 

astrometry worldwide with the aim to raise interest in geodetic and astrometric VLBI among 

students. For this purpose several experts were asked to take care of the different continents:

Continent Responsible team

North America Alan Whitney and Dirk Behrend

South America Hayo Hase and Alan Whitney

Europe Rüdiger Haas and Johannes Böhm

Asia Dirk Behrend and Oleg Titov

Australia and Oceania Oleg Titov and Bjørn Engen

Africa Lucia Plank and Rüdiger Haas

The responsible teams collected information on educational institutes that provide student 

education in geodesy, geosciences and astrometry. Unfortunately is the distribution of such 

institutions not equal for all continents. For some of the continents only a few contact addresses 

could be collected so far. There is more work to be done to collect potential contacts. Below we 

give a list of so far collected contacts addresses.

a) NORTH AMERICA:

Canada

– York University, Earth and Space Science Engineering, Spiros Pagiatakis, spiros (at) yorku.ca

– University of Calgary, Department of Geomatics Engineering, Prof. Michael G. Sideris, 

sideris (at) ucalgary.ca

México

– Universidad Autonoma de México, Departamento de Geodesia y Cartografía, Ing. Bartolo Lara 

Andrade, larandraba (at) gmail.com

– Instituto Politécnico Nacional, Unidad Ticomán Ciencias de la Tierra (ESIA), Ing. Julio 

Morales de la Garza, jmoralesd (at) ipn.mx

USA

– University of Colorado, Prof. Kristine Larson, kristinem.larson (at) gmail.com

– University of Nevada, Prof. Jeff Blewitt, gblewitt (at) unr.edu

– Lamont-Doherty Earth Observatory, Prof. James Davis, jdavis (at) ldeo.columbia.edu

– Ohio State University, Prof. Michael Bevis, mbevis (at) osu.edu

b) SOUTH AMERICA:

Argentina

– Universidad Nacional de La Plata – UNLP, Carrera de Ingeniería en Agrimensura, Dr. Ing. 

Marcos Actis, depagrim (at) ing.unlp.edu.ar

– Universidad Nacional de La Plata – UNLP, Carrera de Geofísica, Decano Dr. Adrián Brunini, 
28

agrimen (at) fi.uba.ar

– Universidad Nacional de Buenos Aires – UNBA, Carrera de Ingeniería en Agrimensura, Dr.

Ing. Carlos Rosito, agrimen (at) fi.uba.ar

– Universidad Nacional de Tucumán – UNT, Carrera de Ingeniería Geodésica y Geofísica, 

Decano Ing. Sergio José Pagani, Dr. José Luis Vacaflor, jvacaflor (at) herrera.unt.edu.ar

– Universidad Nacional de Cordoba – UNC, Carrera de Ingeniería en Agrimensura, Decano 

Hector Gabriel Tavella, Ing. Susana Talquenca, comunicaciones (at) efn.uncor.edu

– Universidad Santiago del Estero, Carrera de Ingeniería en Agrimensura, Decano Héctor Rúben 

Paz, info-fce (at) unse.edu.ar

– Universidad Nacional del Sur – UNS, Carrera de Ingeniería en Agrimensura, Decano Carlos 

Rossit, dtoinge (at) criba.edu.ar

– Universidad Nacional de Catamarca – UNCA, Carrera de Ingeniería en Agrimensura, Rector 

Ing. Flavio Fama

– Universidad de Morón, Carrera de Ingeniería en Agrimensura, Rector Héctor Norberto Porto 

Lemma, ingenieria (at) unimoron.edu.ar

– Universidad Nacional Juan Maza, Carrera de Ingeniería en Agrimensura, Decano Vicente 

Gonzalo Cremades, gorelo (at) umaza.edu.ar

– Universidad Nacional del Litoral – UNL, Carrera de Ingeniería en Agrimensura, Decano Ing. 

Mario Schreider, fich (at) fich.unl.edu.ar

– Universidad Nacional del Nordeste – UNNE, Carrera de Ingeniería en Agrimensura, Decana 

Dra. Lidia Itatí Ferraro de Corona, estudios (at) exa.unne.edu.ar sae (at) exa.unne.edu.ar

– Universidad Nacional del Nordeste – UNNE, Carrera de Ingeniería Civil, Decano Dr. Jorge 

Victor Pilar, info (at) ing.unne.edu.ar

– Universidad Nacional de Rosario – UNR, Carrera de Ingeniería en Agrimensura, Decano Ing.

Elect. Oscar Enrique Peire, secdec@fceia.unr.edu.ar many (at) fceia.unr.edu.ar

Brazil

– UNESP - Universidade Estadual Paulista Júlio de Mesquita Filho, Departamento de 

Cartografia, Dr. João Carlos Chaves, jcchaves (at) fct.unesp.br 

– USP - Universidade de São Paulo, Departamento de Engenharia de Transportes, Dr. Edvaldo 

Simões da Fonseca Junior, edvaldoj (at) usp.br 

– UFRGS - Universidade Federal do Rio Grande do Sul, Departamento de Geodésia, Dra. Andrea 

Lopes Iescheck, andrea.iescheck (at) ufrgs.br 

– UFPE - Universidade Federal de Pernambuco, Departamento de Engenharia Cartográfica, Dr. 

Carlos A. Pessoa M. Galdino, galdino (at) ufpe.br 

– IME - Instituto Militar de Engenharia, Seção de Ensino de Engenharia Cartográfica, Dr. 

Leonardo Castro de Oliveira, se6_chefia (at) ime.eb.br 

– UERJ - Universidade do Estado do Rio de Janeiro, Departamento de Engenharia Cartográfica, 

Dr. Amauri Ribeiro Destri, destri (at) uol.com.br 

– INPE - Instituto Nacional de Pesquisas Espaciais, Serviço de Pós-Graduação, Jose Carlos 

Becceneri, becce@lac.inpe.br posgraduacao (at) pgrad.inpe.br

– ON – Observatório Nacional, Geofísica, Dr. Sergio Luiz Fontes, sergio (at) on.br 

– UFPR - Universidade Federal do Paraná, Engenharia Cartográfica e de Agrimensura, Dr. Luís 

Augusto Koenig Veiga, kngveiga (at) ufpr.br 

Chile

– ACAPOMIL – Academia Politécnica Militar, Jefatura de Estudios, Teniente Coronel Neira, 
29

geografia (at) acapomil.mil

– Universidad de Concepción, Ingeniería Geomática, Dr. Juan Carlos Báez Soto, jbaez (at) 

udec.cl

– Universidad de Santiago de Chile, Ingeniería en Geomensura, Dr. Belfor Portal Valenzuela, 

belfor.portal (at) usach.cl

– Universidad Técnica Metropolitana, Escuela de Geomensura, Luis del Canto Harboe, 

geomensura (at) utem.cl

– Universidad de Antofagasta, Ingeniería en Geomensura, Luis Fernández San Martín, uovando

(at) uantof.cl

– Universidad Bernardo O'Higgins, Ingeniería en Geomensura y Cartografía, Sr. Abel Fuentes, 

geomensura (at) ubo.cl

– Universidad de Talca, Geomática, Yony Ormazábal, yormazabal (at) utalca.cl

– INACAP Maipú, Ingeniería en Geomensura, Sr. René Martínez Muñoz, maipu (at) inacap.cl

Colombia

– Universidad Distrital Francisco José de Caldas, Ingeniería Catastral y Geodesia, Coordinador -

Ingeniería Catastral y Geodesia, ingcatastral (at) udistrital.edu.co

Costa Rica

– Universidad Nacional, Escuela de Topografia Catastro y Geodesia, Steven Oreamuno Herra, 

soreamun (at) una.ac.cr

Ecuador

– Escuela Politecnica del Ejercito, Carrera de Ingenieria Geográfica y Medio Ambiente, Dr 

Alfonso Tierra, fleon (at) espe.edu.ec

– Instituto Geográfico Militar, Proceso de Geodesia, Capitan Nicolay Vaca, nicolay.vaca (at) 

mail.igm.gob.ec

Honduras

– –

Panamá

– Universidad Tecnológica de Panamá, Escuela de Geotecnia Ingenería en Geomática, Chun 

Quan Huang Lin, chun.huang (at) utp.ac.pa

Venezuela

– Universidad de Zulia, Departamento de Geodesia Superior, Escuela de Ingeniería Geodésica, 

Prof. Dr.-Ing. Eugen Wildermann, Prof. Msc-Ing. Karina Acurero, ewildermann (at) 

fing.luz.edu.ve kacurero (at) fing.luz.edu.ve

c) EUROPE:

Albania

– Tirana University, Department of Geography, Prof. Dr. Pal Nikolli, palnikolli (at) yahoo.com

Andorra

– –
30

Austria

– TU Graz, Institute of Theoretical Geodesy and Satellite Geodesy, Prof. Dr. Torsten Mayer-Gürr: mayerguerr (at) tugraz.at

– TU Wien, Institute of Geodesy and Geophysics, Prof. Dr. Johannes Böhm: johannes.boehm (at) 

tuwien.ac.at

Belarus

– –

Belgium

– Royal Observatory of Belgium, Prof. Veronique Dehant, v.dehant (at) oma.be

Bosnia and Herzegovina

– –

Bulgaria

– University of Architecture, Civil Engineering and Geodsy, Department of Geodesy, Prof. Georgi Mitrev, 

gmitrev_fgs (at) uacg.bg

Croatia

– University of Zagreb, Faculty of Geodesy, Institute of Geomatics, Prof. Zeljko Bacic, zbacic 

(at) geof.hr

Cyprus

– –

Czech Republic

– Research Institute of Geodesy Topography and Cartography, Department of Geodesy and Geodynamics,

Prof. Dr. Jakub Kostelecky, kakub.kostelecky (at) pecny.cz

– Czech Technical University in Prague, Department of Advanced Geodesy, Prof. Dr.Ing. Leoš Mervart, 

k152 (at) fsv.cvut.cz 

– Brno University of Technology, Institute of Geodesy, Prof. Otakar Svabensky, svabensky.o (at) 

fce.vutbr.cz

– VSB – Technical University of Ostrava, Faculty of Mining and Geology, Institute of Geoinformatics, 

Prof. Dr. Zdenek Divis, zdenek.divis (at) vsb.cz

– Charles University in Prague, Faculty of Mathematics and Physics, Department of Geophysics, Prof. 

Zdenek Martinec, zdenek (at) hervam.troja.mff.cuni.cz

Denmark

– Aalborg University (AAU), Kai Borre, borre (at) es.aau.dk

– Technical University of Denmark (DTU), Niels Andersen, na (at) space.dtu.dk

– Technical University of Denmark (DTU), Per Knudsen, pk (at) space.dtu.dk

Estonia

– University of Tartu, 

– University of Tallinn‚ Artu Ellman, Harli Jurgensen

Finland

– Aalto University, Martin Vermeer, martin.vermeer (at) aalto.fi

– Finnish Geodetic Institute (FGI), Markku Poutanen, martin.poutanen (at) fgi.fi
31

France

– –

Georgia

– –

Germany

– Bonn University, PD Axel Nothnagel, nothnagel (at) uni-bonn.de

– TU München, Prof. Hugentobler, urs.hugentobler (at) bv.tum.de

– Karlsruhe Institute of Technology, Prof. Heck, bernhard.heck (at) kit.edu

– Stuttgart University, Prof. Nico Sneuw

– Leibniz University Hannover, Prof. Jürgen Müller, mueller (at) ife.uni-hannover.de

Greece

– –

Hungary 

– –

Iceland 

– –

Ireland 

– –

Italy

– –

Kazakhstan 

– –

Latvia

– Univertity of Latvia, Prof. Janis Kaminski, janis.kaminski (at) gmail.com

Liechtenstein

– –

Lithuania

– –

Luxembourg

– University of Luxembourg, Prof. Olivier Francis, olivier.francis (at) uni.lu

– University of Luxembourg, Prof. Felix Norman Teferle, norman.teferle (at) uni.lu

– University of Luxembourg, Prof. Tonie van Dam, tonie.vandam (at) uni.lu

Republic of Macedonia 

– State University of Tetova, Faculty of Natural Sciences and Mathematics, Prof. Dr. Bashkim 

Idrizi, bashkim.idrizi (at) unite.edu.mk
32

Malta, Moldova, Monaco, Montenegro

– –

Netherlands

– Delft University of Technology, Prof. Ambrosius, b.a.c.ambrosius (at) tudelft.nl

Norway

– University Ås, Geomatics, Bjørn Rangvald Pettersson 

– University Ås, Oddgeir Kristiansen

Poland

– Polish Academy of Sciences, Space Research Centre, Prof. Dr. Aleksander Brzezninski, alek 

(at) cbk.waw.pl

Portugal

– –

Romania

– –

Russia

– St.Petersburg University, St Petersburg, Prof. Veniamin Vityazev

San Marino, Serbia, Slovakia, Slovenia

– –

Spain

– –

Sweden

– Royal Institute, Stockholm, Prof. Lars Sjöberg

– Högskolan i Gävle, Stieg-Göran Mårtensson

Switzerland

– ETH Zürich, Prof. Markus Rothacher,

– University Bern, Rolf Dach

Turkey

– –

Ukraine

– –

United Kingdom

– University of Nottingham, Prof. Terry Moore

– Newcastle University, Prof. Matt King, m.a.king (at) ncl.ac.uk
33

Vatican City

– –

d) ASIA:

Afghanistan

– –

Armenia

– –

Azerbaijan

– –

Bahrain

– –

Bangladesh

– –

Bhutan

– –

Brunei

– –

Burma (Myanmar)

– –

Cambodia

– –

China

– Wuhan University, Prof. Erhu Wei, ehwei (at) sgg.whu.edu.cn

Hong Kong

– –

India

– –

Indonesia

– –

Iran

– –
34

Iraq

– –

Israel

– –

Japan

– Sapporro University, Prof. Kosuke Heki

Jordan

– –

Kazakhstan

– –

Korea, North

– –

Korea, South

– –

Kuwait

– –

Kyrgyzstan

– –

Laos

– –

Lebanon

– –

Malaysia

– –

Maldives

– –

Mongolia

– –

Myanmar

– –

Nepal

– –

Oman

– –
35

Pakistan

– –

Philippines

– –

Qatar

– –

Saudi Arabia

– –

Singapore

– –

Sri Lanka

– –

Syria

– –

Taiwan

– –

Tajikistan

– –

Thailand

– –

Turkey

– –

Turkmenistan

– –

United Arab Emirates

– –

Uzbekistan

– –

Vietnam

– –

Yemen

– –

e) Australia and Oceania
36

Australia

– –

Fiji

– –

Kiribati

– –

Marshall Islands

– –

Micronesia

– –

Nauru

– –

New Zealand

– –

Palau

– –

Papua New Guinea

– –

Samoa

– –

Solomon Islands

– –

Tonga

– –

Tuvalu

– –

Vanuatu

– –

f) Africa

Algeria

– –
37

Angola

– –

Benin

– –

Botswana

– –

Burkina Faso

– –

Burundi

– –

Cameroon

– –

Cape Verde

– –

Central African Republic

– –

Chad

– –

Comoros

– –

Congo-Brazzaville

– –

Congo-Kinshasa

– –

Cote d'Ivoire

– –

Djibouti

– –

Egypt

– –
38

Equatorial Guinea

– –

Eritrea

– –

Ethiopia

– –

Gabon

– –

Gambia

– –

Ghana

– –

Guinea

– –

Guinea Bissau

– –

Kenya

– –

Lesotho

– –

Liberia

– –

Libya

– –

Madagascar

– –

Malawi

– –

Mali

– –

Mauritania

– –

Mauritius

– –
39

Morocco

– –

Mozambique

– –

Namibia

– –

Niger

– –

Nigeria

– –

Rwanda

– –

Senegal

– –

Seychelles

– –

Sierra Leone

– –

Somalia

– –

South Africa

– Hartebeesthoek Radio Astronomical Observtory, Prof. Ludwig Combrinck, ludwig (at) 

hartrao.ac.za

South Sudan

– –

Sudan

– –

Swaziland

– –

São Tomé and Príncipe

– –

Tanzania

– –
40

Togo

– –

Tunisia

– –

Uganda

– –

Western Sahara

– –

Zambia

– –

Zimbabwe
41

ToR-2

The task was to develop education material that can be distributed to education institutions.

The WG decided to start by collecting existing educational material. Material provided by 

Johannes Böhm and Harald Schuh from the Vienna Technical University, Austria, Chris Jacobs 

from the Jet Propoulsion Laboratory, USA, and Rüdiger Haas from Chalmers University of 

Technology, Sweden. The material consists of pdf-files and is available at

http://www.evga.org/edumaterial.html

As a next step, the plan was to collect and compile the material presented at the IVS VLBI 

school. This material consists of 14 lectures and 3 exercises and is available at

http://www.evga.org/material_vlbi_school_2013.html , see Figure 1 below.

Figure 1 Webpage http://www.evga.org/material_vlbi_school_2013.html with the lecture 

material developed for the EGU and IVS Training school on VLBI for Geodesy and 

Astrometry, held in Espoo and Masala, Finland, March 2-5, 2013. 
42

ToR-3

The task was to seek funding and to develop a concept and prepare the organization of training in 

form of for example IVS summer schools for master and PhD students.

Several attempts were done to apply for funding for a VLBI-school:

The first attempt was directed in the spring of 2011 towards NordForsk. NordForsk is an 

organisation under the Nordic Council of Ministers that provides funding for Nordic research 

cooperation as well as advice and input on Nordic research policy. We sent in an application to 

NordFork’s call for ”Research Training Courses 2011” and applied for about 230 kNOK funding 

of a VLBI-school that was planned for the summer of 2011. For this call, NordForsk received in 

total 52 applications, out of which 20 were funded. Unfortunately, our application did not get any 

support.

The second attempt was an application to the “Training of Radio Astronomers” program of 

RadioNet. RadioNet is a project supported by the European Commission under the 7th 

Framework Programme (FP7). A support by RadioNet on the order of up to 2 k€ was granted for 

the organisation of a VLBI-school.

The third attempt was an application to the European Geosciences Union (EGU) in the fall of 

2011. We submitted a proposal for a VLBI-school to the “Topical Meetings and Training Schools 

for 2012” program of the EGU outreach committee. We applied for a total budget of 23.5 k€ to 

organise a VLBI-school in the late summer of 2012 at Onsala. In November 2011 the EGU 

informed us that they would support the VLBI-school by 5 k€.

Since we so far had only 7k€ support from RadioNet and EGU, we decided to organise the 

VLBI-school not as a stand-alone occasion, but in connection to another VLBI-related meeting. 

We anticipated that this would make it easier for teachers and students to participate. We chose 

the EVGA meeting in March 2013 in Finland and EGU agreed to move the VLBI-school to 2013. 

We also discussed further support for the VLBI-school with the Aalto University in Espoo, the 

Finnish Geodetic Institute in Masala, and the Onsala Space Observatory. These three institutions 

granted additional support in terms of access to lecture halls, bus transport, coffee breaks, 

lunches, and a school dinner. The logos of the sponsors of the VLBI-school are presented in 

Figure 2. IVS supported the VLBI-school though teachers that are members of IVS. A report on 

the VLBI-school is given on the following pages.

Figure 2 The logos of the sponsors of the EGU and IVS Training School on VLBI for 

Geodesy and Astrometry, held in March 2013 in Finland.
43

Report on the

EGU and IVS Training School 

on VLBI for Geodesy and 

Astrometry

Held 2013, March 2-5, at Aalto University, Espoo (Finland) and the Finnish 

Geodetic Institute, Masala (Finland)

Rüdiger Haas, Markku Poutanen, Minttu Uunila, 2013-04-22

A) GENERAL INFORMATION

The “EGU and IVS Training School on VLBI for Geodesy and Astrometry” was held March 2-5, 

2013, in Finland. It was organized by Rüdiger Haas, head of IVS Working Group 6 on VLBI 

Education, in collaboration with Markku Poutanen, head of the geodesy division at the Finnish 

Geodetic Institute (FGI), and Minttu Uunila from Aalto University, Metsähovi Radio 

Observatory, Finland. The main goal of the VLBI school was to educate and provide training for 

the next generation VLBI researchers that will work with the next generation VLBI system for 

Geodesy and Astrometry. For that purpose, four days of lectures and exercises were arranged, 

with the intention to cover the VLBI system for Geodesy and Astrometry as complete as possible. 

The lectures covered technical aspects, scheduling and observations, details of the correlation 

process, modeling and data analysis, and interpretation of the results. There were in total 14 

lectures and 3 hands-on exercises. Some impressions on the activities during the VLBI-school are 

shown in Figures 3-6. The final session of the VLBI-school was held together with the 14th IVS 

Analysis Workshop.
44

The teachers that were giving lectures at the VLBI school are international experts in their fields 

and come from several research institutions worldwide:

· Thomas Artz (University of Bonn, Germany) 

· Alessandra Bertarini (Max Planck Institute for Radioastronomy, Germany) 

· Johannes Böhm (Vienna Technical University, Austria) 

· Roger Cappallo (MIT Haystack Observtory, USA) 

· Patrick Charlot (Bordeaux Observatory, France) 

· John Gipson (NASA, NVI Inc., USA) 

· Rüdiger Haas (Chalmers University of Technology, Sweden)

· Chris Jacobs (JPL, NASA, USA) 

· Dan MacMillan (NASA, NVI Inc., USA) 

· Axel Nothnagel (University of Bonn, Germany) 

· Bill Petrachenko (National Resources Canada, Canada) 

· Harald Schuh (GeoForschungsZentrum Potsdam, Germany) 

· Manuela Seitz (DGFI, Germany)

· Alan Whitney (MIT Haystack Observatory, USA)

There were more than 60 applications for participation in the VLBI school, from interested 

students worldwide, including all continents. Finally, more than 50 students really could attend 

the VLBI-school, see the list of participants in Section 3. More than 50 % of the participants are 

active in educational programs on master’s or PhD level, while the rest were more senior 

researchers. More than 35 % of the participants were female. The lecture slides are available via 

the webpages of the European VLBI Group for Geodesy and Astrometry (EVGA, 

www.evga.org/material_vlbi_school_2013.html).

The VLBI-school received some financial support from the European Geosciences Union (EGU) 

that was entirely used to support parts of the travel expenses of the master’s and PhD students. 

The Onsala Space Observatory provided support for food in terms of coffee breaks and lunches

during the VLBI-school. Aalto University provided the lecture room on Saturday, Monday and 

Tuesday, while the Finnish Geodetic Institute provided the lecture room on Sunday and some 

food. A small number of master’s and PhD students sent in claims to RadioNet3 and were

refunded for additional travel expenses.
45

 

 

Figure 4: Alessandra Bertarini giving a lecture for the VLBI-school at the 

Finnish Geodetic Institute, Masala.

Figure 3: Students listening to a lecture during the VLBI-school in the lecture 

hall at Aalto University, Espoo.
46

 

 

Figure 6: Axel Nothnagel (left) supervising a student group during Exercise-3 

on data analysis.

Figure 5: Roger Cappallo (right) advising a student group during Exercise-2 on 

software correlation.
47

B) THE PROGRAM OF THE TRAINING SCHOOL 

Day-1 (Saturday, 2013-03-02, @ Aalto University, Espoo)

09:00-09:15 Welcome and practical information (R. Haas, M. Poutanen) 

09:15-10:00 "General overview on geodetic and astrometric VLBI and the IVS" (H. Schuh)

10:00-10:30 --- coffee break ---

10:30-12:00 "Radio telescopes, feed horns and receivers" (B. Petrachenko)

12:00-13:00 --- lunch break ---

13:00-14:30 "Digital backends and data acquisition" (A. Whitney)

14:30-15:00 --- coffee break ---

15:00-16:30 "Experiment scheduling" (J. Gipson)

16:30-17:15 "Observing an experiment" (R. Haas)

17:15-18:00 Exercise-1 (theoretical calculations, B. Petrachenko)

Day-2 (Sunday, 2013-03-03, @ FGI, Masala) 

08:30-09:00 bus leaves from Helsinki downtown to Radissson blu Otaniemi Espoo

09:00-09:30 bus leaves from Radiosson blu Otaniemi Espoo to FGI Masala 

09:30-11:00 "Correlator Architectures and VLB2010" (R. Cappallo)

11:00-11:30 --- coffee break ---

11:30-13:00 "Correlation preparation and post-correlation analysis" (A. Bertarini)

13:00-14:00 --- lunch break ---

14:00-15:30 "Geophysical models" (D. MacMillan)

15:30-16:00 --- coffee break ---

16:00-17:30 Exercise-2 (software correlation) (A. Bertarini & R. Cappallo)

17:30-20:00 "VLBI-school dinner" 

20:00-21:00 bus transport back to Radiosson blu Otaniemi Espoo & Helsinki downtown

Day-3 (Monday, 2013-03-04, @ Aalto University, Espoo)

09:00-10:30 "Atmospheric propagation" (J. Böhm) 

10:30-11:00 --- coffee break ---

11:00-12:30 "Data modeling and analysis" (Th. Artz)

12:30-13:30 --- lunch break ---

13:30-15:00 "Terrestrial reference frame" (R. Haas on behalf of M. Seitz)

15:00-15:30 --- coffee break ---

15:30-17:00 Exercise-3 (data analysis) (Th. Artz et al.)

Day-4 (Tuesday, 2013-03-05, @ Aalto University , Espoo)

09:00-10:30 "Radio sources" (P. Charlot)

10:30-11:00 --- coffee break ---

11:00-12:30 "Celestial Reference Frames" (Ch. Jacobs)

12:30-13:30 --- lunch break ---

13:30-15:00 "Earth rotation and orientation" (A. Nothnagel)

15:00-15:30 --- coffee break ---

15:30-18:00 14th IVS Analysis Workshop (A. Nothnagel et al.)
48

C) DISCUSSION AND EVALUATION OF THE TRAINING SCHOOL

The event was a Training School on VLBI for Geodesy and Astrometry with in total 14 lectures 

and 3 exercises. All lectures were 90 minutes long, except one that was only 45 minutes long. 

The exercises were between 45 and 90 minute long, and very much appreciated by the students. 

The first exercise covered purely technical aspects and focused on aspects like the calculation of 

sensitivity of radio astronomical systems. The students worked individually and had to solve 

several small tasks. The second exercise was on software correlation. The students worked in 

small groups of 4-5 persons and used the DiFX software correlator and the Haystack fringefitting software to derive VLBI group delay observables for the baseline Wettzell-Onsala of a real 

experiment. The third exercise then concentrated on the analysis of geodetic VLBI data. The 

students worked again in small groups of 4-5 people and performed the necessary ambiguity 

resolution and ionospheric corrections, and the final parameter estimation.

There was plenty of opportunity for the students to ask questions after the lectures, and there 

were lively discussions in the coffee breaks and lunch breaks. The students had access to all 

teachers and could ask questions and discuss various topics. 

At the end of the last day an evaluation questionnaire was handed out to the students and they 

were asked to evaluate the VLBI Training School. Copies of the original answers can be provided 

on request. A summary of the results of the evaluation is presented below.

 

Figure 7: Question: “What is your impression on the exercises ‘technique’ 

(Exercise-1), ‘correlation’ (Exercise-2) and ‘analysis’ (Exercise-3) that we did 

during the VLBI school”?
49

 

 

Figure 9: Question: “What was/is your knowledge on ‘digital backends and data 

acquisition’ before and after the VLBI school”?

Figure 8: Question: “What was/is your knowledge on ‘radio telescopes, feed horns 

and receivers’ before and after the VLBI school”?
50

 

 

Figure 11: Question: “What was/is your knowledge on ‘correlator architecture’ 

before and after the VLBI school”?

Figure 10: Question: “What was/is your knowledge on ‘experiment scheduling’ 

before and after the VLBI school”?
51

 

 

Figure 13: Question: “What was/is your knowledge on ‘geophysical models’ before 

and after the VLBI school”?

Figure 12: Question: “What was/is your knowledge on ‘correlation and postcorrelation analysis’ before and after the VLBI school”?
52

 

 

Figure 15: Question: “What was/is your knowledge on ‘data modeling and analysis’ 

before and after the VLBI school”?

Figure 14: Question: “What was/is your knowledge on ‘atmospheric propagation’ 

before and after the VLBI school”?
53

 

 

Figure 17: Question: “What was/is your knowledge on ‘radio sources’ before and 

after the VLBI school”?

Figure 16: Question: “What was/is your knowledge on ‘terrestrial reference frames’ 

before and after the VLBI school”?
54

 

 

Figure 19: Question: “What was/is your knowledge on ‘earth rotation and 

orientation’ before and after the VLBI school”?

Figure 18: Question: “What was/is your knowledge on ‘celestial reference frames’ 

before and after the VLBI school”?
55

The evaluation shows that the three exercises were appreciated by the students and evaluated as

‘good’ to ‘very good’. Several participants answered in the free-text comments of the evaluation 

questionnaire that the practical exercises were the best part of the VLBI Training School. There 

was however also some concern that the time was too short to work on some of the exercises. 

Some participants thought that there should be even more exercises during potential future VLBI 

Training Schools.

The evaluation also shows that the personal impression of the participants is that they know more 

on the particular topics after the VLBI Training School than before. More people feel that they 

have ‘good’ and ‘very good’ knowledge after the VLBI Training School. So there appears to be 

again in knowledge and the goal to provide education and training has been achieved to a large 

extend. Many of the free-text comments on the lectures said that the lectures gave a very good 

overview of all features of VLBI. 

The lecture slides are available at the webpages of the European VLBI Group for Geodesy and 

Astrometry (EVGA, www.evga.org/material_vlbi_school_2013.html). The intention is that they 

can be used as a basis for teaching at educational institutes.

The IVS Directing Board had a directing board meeting in Metsähovi on March 8, after the 

“EGU and IVS Training School on VLBI for Geodesy and Astrometry”. The IVS DB regarded 

that the “EGU and IVS Training School on VLBI for Geodesy and Astrometry” held in Espoo 

and Masala was a success. For the next IVS DB in the fall of 2013 a final report of the IVS WG 6 

needs to be prepared, so that IVS WG 6 can be closed down. However, then an IVS Committee 

on Training and Education shall be established, with the task to continue the work started by IVS 

WG 6. It is anticipated to organize VLBI Training Schools on a regular basis, preferably every 

third year alternating in connection with the IVS General Meetings and the European VLBI 

meetings.
56

D) ATTENDANCE LIST

There were 43 participants in the VLBI Training School coming from 16 different countries. The 

countries with more than 1 participant were Germany (10), Finland (7), Austria (6), France (3), 

China (3), Norway (2), Australia (2) and the Netherlands (2). The distribution of the countries is 

presented in Figure 20. A group photo taken on the second day of the VLBI Training School 

when lectures and exercise were held at the headquarters of the Finnish Geodetic Institute (FGI) 

in Masala, is shown in Figure 21.

 

 

Figure 21: The participants of the “EGU and IVS Training School on VLBI for 

Geodesy and Astrometry” on Sunday, March 2, 2013, at the Finnish Geodetic

Institute, Masala, Finland.

Figure 20: Distribution of participants of the “EGU and IVS Training School on 

VLBI for Geodesy and Astrometry” per country.
57

LIST OF PARTICIPANTS:

Bachmann, Sabine

Federal Agency for Cartography and Geodesy

Richard-Strauss-Allee 11

DE-60598 Frankfurt am Main

Germany

(Sabine.Bachmann@bkg.bund.de)

Bocanegra-Bahamón, Tatiana Marcela 

Joint Institute For VLBI In Europe

P.O. Box 2

NL-7990 AA Dwingeloo

The Netherlands

(bocanegra@jive.nl)

Bouffet, Romuald

Laboratoire d'Astrophysique de Bordeaux (LAB)

Observatoire Aquitain des Sciences de l'Univers

Université Bordeaux 1 - CNRS UMR 5804

2 rue de l'Observatoire

BP89 

FR-33271 Floirac Cedex

France

(bouffet@obs.u-bordeaux1.fr)

Collilieux, Xavier

IGN/LAREG

Université Paris Diderot

35 rue Hélène Brion

FR-75013 Paris

France

(xavier.collilieux@ign.fr)

de Witt, Aletha

Hartebeesthoek Radio Astronomy Observatory

Farm 502 JQ, Hartebeesthoek

Broederstroom Road

Krugersdorp District, Gauteng

South Africa

(alet@hartrao.ac.za)

Esch, Christina

Kirschenallee 7

DE-53879 Euskirchen

Germany

(christina.esch@web.de)
58

García-Espada, Susana

Centro de Desarrollos Tecnológicos

Subdirección General de Astronomía, Geodesia y Geofísica

D.G.IGN (Ministerio de Fomento)

Cerro de la Palera s/n

ES‐19141 Yebes (Guadalajara)

Spain

(s.gespada@oan.es)

Halsig , Sebastian

Institut f r Geod sie und Geoinformation

Nußallee 17

DE‐53115 Bonn

Germany

(halsig@igg.uni-bonn.de)

Iddink , Andreas

Institut fürGeodäsie und Geoinformation

Nußallee 17

DE-53115 Bonn

Germany

(aiddink@uni-bonn.de)

Kallio, Ulla

Finnish Geodetic Institute

Geodeetinrinne 2

P.O. Box 15

FI-02431 Masala

Finland

(ulla.kallio@fgi.fi)

Karbon, Maria

Advanced Geodesy Institute of Geodesy and Geophysics (E128)

TU Wien

Gußhausstr. 27‐29

AT‐1040 Wien

Austria

(mkarbon@mail.zserv.tuwien.ac.at)

Kareinen, Niko

Aalto University

Metsähovi Radio Observatory

Metsähovintie 114

FI-02540 Kylmälä

Finland

(nkareine@kurp.hut.fi)
59

Kirkvik Ann-Silje

Kartverket

Kartverksveien 21

NO-3511 Hønefoss

Norway

(Ann-Silje.Kirkvik@kartverket.no)

Krásná Hana

Department für Geodäsie und Geoinformation

Technische Universität Wien

Gußhausstraße 27-29

AT-1040 Wien

Austria

(hana.krasna@tuwien.ac.at)

Kunkel, Annemarie 

Institut für Geodäsie und Geoinformation

Nußallee 17

DE-53115 Bonn

Germany

(s6ankunk@uni-bonn.de)

Madzak, Matthias

Department für Geodäsie und Geoinformation

Technische Universität Wien

Gusshausstraße 27-29

AT-1040 Wien

Austria

(matthias.madzak@tuwien.ac.at)

McCallum Jamie

University of Tasmania

School of Mathematics and Physics

Private Bag 37

Hobart TAS 7001

Australia

(Jamie.McCallum@utas.edu.au)

Meschini, Diego

Finnish Geodetic Institute

Geodeetinrinne 2

P.O. Box 15

FI-02431 Masala

Finland

(diego.meschini@fgi.fi)

Mishra, Aum Niranjana
60

Franz‐Mehring‐Platz 3

Zi. Nr. 27.30.16.82

DE‐10243 Berlin

Germany

(niranjana.mishra@yahoo.com)

Molera-Calvés, Guifré

Joint Institute for VLBI in Europe

Oude Hoogeveensedijk 4

NL-7991 Dwingeloo

The Netherlands

(molera@jive.nl)

Mora-Diaz, Julian Andres

Technische Universität München

Fachgebiet Satellitengeodäsie

Arcisstraße 21

DE-80333 München

Germany

(Mora@dgfi.badw.de)

Orosz, Gábor

Department of Geodesy and Surveying

Budapest University of Technology and Economics

Müegyetem rkp. 3

HU–1111 Budapest

Hungary

(gabor.orosz@gmail.com)

Plank, Lucia

Technische Universität Wien

Department für Geodäsie und Geoinformation

Forschungsgruppe Höhere Geodäsie, E120/4

Gußhausstraße 27-29,

AT‐1040 Wien

Austria

(lucia.plank@tuwien.ac.at)

Ramakrishnan,Venkatessh

Aalto University

Metsähovi Radio Observatory

Metsähovintie 114

FI-02540 Kylmälä

Finland

(venkatessh.ramakrishnan@aalto.fi)

Raposo-Pulido, Virginia
61

Helmholtz‐Zentrum Potsdam

DeutschesGeoForschungsZentrum GFZ

Telegrafenberg, A17

DE-14473 Potsdam

Germany

(raposo@gfz-potsdam.de)

Rastorgueva-Foi, Elizaveta

Aalto University, Metsähovi Radio Observatory

Metsähovintie 114

FI-02540 Kylmälä

Finland

(elizaveta.rastorgueva@aalto.fi)

Schönberger, Caroline

Josef‐Gall‐Gasse 3/5

AT‐1020 Wien

Austria

(casch@gmx.at)

Searle, Anthony

Natural Resources Canada

Geodetic Survey Division

615 Booth Street

Ottawa, Ontario

K1A 0E9

Canada

(Anthony.Searle@NRCan-RNCan.gc.ca)

Shabala, Stanislav 

University of Tasmania

School of Mathematics and Physics

Private Bag 37

Hobart TAS 7001

Australia

(Stanislav.Shabala@utas.edu.au)

Shang, Luyao

VLBI Laboratory

Shanghai Astronomical Observatory

Chinese Academy of Sciences 

80 Nandan Road

Xuhui District

Shanghai City

China

(shly@shao.ac.cn)
62

Siebert, Moritz Ny-Ålesund

Geodetic Observatory

NO-9173 Ny-Ålesund

Norway

(moritz.sieber@kartverket.no)

Soja, Benedikt

Forschungsgruppe Höhere Geodäsie / E‐120‐4

Department für Geodäsie und Geoinformation

Technische Universität Wien

AT‐1040 Wien

Austria

(b.soja@gmx.at)

Stetter, Monika

Forschungseinrichtung Satellitengeodäsie (FESG)

Technische Universität München (TUM)

DE‐80290 München

Germany

(m.stetter@tum.de)

Teke, Kamil

Hacettepe University

Department of Geomatics Engineering

Beytepe

TR-06800 Ankara

Turkey

(kteke@hacettepe.edu.tr)

Tornatore, Vincenza

DIIAR Politecnico di Milano

(Sezione rilevamento)

Piazza Leonardo da Vinci 32

IT-20133 Milano

Italy

(vincenza.tornatore@polimi.it)

Trofimov, Dmitrii

Astronomical Institute St. Petersburg State University

Universitetskaya nab 7-9

St. Petersburg

Russia

(dm.trofimov@gmail.com)

Tkachuk, Vadym 

Taras Shevchenko National University of Kyiv

Glushkova ave. 4

UA-03127 Kyiv
63

Ukraina

(vadimol92@gmail.com)

Ullrich, Dieter

Bundesamt für Kartographie und Geodäsie

VLBI-Gruppe

Karl-Rothe-Straße 10-14

DE-04105 Leipzig

Germany

(dieter.ullrich@bkg.bund.de)

Uunila, Minttu

Aalto University, Metsähovi Radio Observatory

Metsähovintie 114

FI-02540 Kylmälä

Finland

(minttu.uunila@aalto.fi)

Verma, Ashok Kumar

Observatoire de Besançon

BP 1615

FR-25010 Besançon

France

(ashok@obs-besancon.fr)

Zhang, Jinwei

Shanghai Astronomical Observatory

Chinese Academy of Sciences

80 Nandan Road

CN-200030 Shanghai

China

(jwzhang@shao.ac.cn)

Zubko, Nataliya

Finnish Geodetic Institute

Geodeetinrinne 2

P.O. Box 15

FI-02431 Masala

Finland

(nataliya.zubko@fgi.fi)

Xu, Minghui

Shanghai Astronomical Observatory

Chinese Academy of Sciences

80 Nandan Road

CN-200030 Shanghai

China

(mhxu@shao.ac.cn)
64

VGOS Data Recorder Comparison

Compiled by Bill Petrachenko (NRC Canada) & Alan Whitney (MIT Haystack Observatory)

June 2013

Introduction.

The minimum VGOS data rate requirements are 16 Gbps ’burst’ for 10 sec with ~4 Gbps sustained average 

rate. This is based on a typcial VGOS schedule which alternates between on-source and slew/wait/cal 

periods with antennas being on source about 25% of the time (but could be greater under some 

circumstances) and the network slewing to the next source the rest of the time. The maximum on-source 

period for normal operations is set to 10 s but could be longer at times to achieve greater sensitivity.

At the present time only two VLBI data recorders fully satisfy VGOS operational requirements, the Mark 6

(already available) and the K6/iDAS (still under development). Because the K6/iDAS does not support 

removable media, it can only be used for e-transfer and not for physical transport of media. See Table 1 

for more details.

Another pair of recorders, the Mark 5C and K5/VSI do not themselves meet VGOS data rate requirements. 

They are however close enough that if preceeded by an external RAM buffer or combined in a group of 

four (plus some format conversions for the K5/VSI), they would become compliant. This solution is 

neither cost effective nor convenient and hence the Mark 5C and K5/VSI are not recommended for use in 

VGOS. See Table 2 for more details.

For completeness, other VLBI data recorders that are still in use but not suitable for VGOS are summarized 

in Tables 3a and 3b.

Fully Compliant VGOS Data Recorders, Table 1

Mark 6. The Mark 6 recorder is an outgrowth of the Haystack/Conduant Mark 5 development. Like its 

predecessor, the Mark 5C, I/O is based on fixed length Ethernet packets (e.g. VDIF), with the output being

an exact replica of the input. Like all Mark 5/6 systems, recording media is removable and packaged as 

8-disk SATA modules. Mechanically the Mark 6 includes a system enclosure, a disk module enclosure, and 

a cable management panel, all produced by Conduant. In terms of data electronics there has been a 

marked shift toward COTS components with only the disk-module-related hardware produced by 

Conduant; the motherboard (MB), NIC, and disk interface cards are all COTS. In contrast to the Mark 5 

family that uses a proprietary Conduant media file-system format, the Mark 6 uses standard Linux files 

with ’scattered’ data. All software has been developed at Haystack and is open source. The Mark 6 is 

ideally suited for use in VGOS. It has four 10GigE inputs (one per VGOS band), a maximum aggregate 

input data rate of a minimum of 16 Gbps into ~64GB of high-speed RAM, and a sustained record rate per 

installed disk module of ~7 Gbps (for mechanical disks; much higher for SSDs). Hence, it is possible to 

achieve a sustained record rate significantly greater than the VGOS requirement (~4 Gbps) using only a 

single 8-disk module, thus minimizing shipping costs. In order to support sustained rates up to 16Gbps or 

to support unattended operation over longer periods at lower rates, as many as four 8-disk media 

modules can be simultaneously mounted. Options are available to upgrade existing Mark 5 systems to 

Mark 6, as well as to upgrade existing Mark 5 SATA disk modules to Mark 6 compatibility.

K6/iDAS. The K6/iDAS means the ``K6 intelligent Data Acquisition and Streaming’’ system, which is the 

name of the sampler with DBBC for VGOS operation developed in Japan. There is no dedicated recorder 

to the K6/iDAS sampler because it allows us to use itself with a fully COTS server, 10GigE-network switch, 

and storage system as recorder. You can adopt a server with a 10GigE network interface and a large 

amount of RAID as a recorder for K6/iDAS. GSI adopted IBM System x3650 M3, Arista 7050S64-T, Data 

Direct Networks (DDN) Storage with StorNext to be compliant with a sustained record rate of 32 Gbps, 

which leaves room for future enhancement of the VGOS requirements. The recording system adopted by 

GSI does not support removable media so it can only be used for e-transfer and not for physical transport 

of media. It also does not support the IVS standard VSI-S control protocol but is controlled directly by 

logging into the system.
65

Mark 6

K6/iDAS

(the recording system adoped 

by GSI)

 VGOS Compatibility Full eVLBI (yes)

Media physical transport (no)

Data Input Connection 4x10GigE 2x10GBASE-SR

Max data-rate per input 

connection 8 Gbps 8 Gbps

Max aggregate input data rate 16 Gbps 32 Gbps (4 sampler units/8

servers)

Max sustained record rate

~7 Gbps x # of media packages 

installed (for hard disks);

much faster for SSDs

32 Gbps

RAM buffer size 64 Gbyes (~30 s at 16 Gbps) N. A.

Removable media? Y N

Recording media packaging Mk6 8-disk SATA module SATA & SAS Linux RAID with 

StoreNext

Max # of media packages per 

system

4 1

# media packages for max 

recording data rate

2 to 4 depending on speed of 

disks 1

Input data format VDIF or Mk5B Ethernet packets VDIF (UDP/IP)

Record-data format VDIF VDIF

Media file-system format Linux files w/’scattered’ data Linux files

Resilient to slow recording 

media? Y Y

Max aggregate playback rate Up to 16 Gbps (depends on 

playback system details) 32 Gbps

Playback data interface type 10GigE or Infiniband 1x10GigE x 16 servers

Playback data format Recorded data payload

in Ethernet frame VDIF

OS type Linux Linux

Software developer

(’proprietary’ or ’open’) Haystack (open) GSI/Nitsuki(open by GSI)

Command interface 

connection GigE GigE

Command language VSI-S

Direct control by logging into 

the system

Current status Available Under development, partially 

available

Cost (USD) ~$14K USD depend on rate and capacity

Contact <mark6@haystack.mit.edu> Shinobu Kurihara

<skuri@gsi.go.jp>

Table 1. VGOS Data Recorders – systems fully meeting the VGOS specification. However, the K6/iDAS 

does not support removable media and hence only works at stations dedicated to eVLBI.
66

Potentially Compliant (but not recommended) VGOS Data Recorders, Table 2

Mark 5C. The Mark 5C recorder is an outgrowth of the Haystack/Conduant Mark 5 development. In 

contrast to its predecessors, I/O is based on fixed length Ethernet packets (e.g. VDIF) with the output 

being an exact replica of the input. Like all Mark 5 systems, recording media is removable and packaged 

as Mk5 8-disk PATA or SATA modules. Mechanically the Mark 5C includes a system and disk–module 

enclosure produced by Conduant. Its data electronics include a standard COTS motherboard and disk 

array interface, 10GigE daughterboard and data distributor produced by Conduant. The Mark 5C could 

conceivably be adapted to support VGOS if four Mark 5’s were used at each station or if it were 

preceeded in the signal chain by a burst mode RAM buffer, but these options are neither cost effective 

nor convenient; hence the Mark 5C is not recommended for VGOS.

K5/VSI. The K5/VSI is a VSI-H based VLBI recorder using K5 data-frame format. It is housed in a standard 

PC enclosure with a proprietary PC-VSI board from Digital Link and a COTS NIC and disk interface. The 

K5/VSI could conceivably be adapted to support VGOS if four K5/VSI’s were used at each station of if it 

were preceeded in the signal chain by a burst mode RAM buffer, but these options are neither cost 

effective nor convenient. Hence the K5/VSI is not sufficient for VGOS. The K5/VSI does not support 

removable media so it can only be used for e-transfer and not for physical transport of media. Finally, it 

does not support the standard IVS VSI-S control protocol but is controlled directly by logging into the 

system at present. Since the recoriding is totally controlled by the software on standard linux, this feature 

can be improved by software cording on the linux OS without any difficulty. 

Mark 5C K5/VSI

VGOS Compatibility Requires 4 systems or the 

addition of a burst mode buffer.

Requires 4 systems or the 

addition of a burst mode buffer, 

plus VSI-H to VDIF converter.

Data Input Connection 10GigE VSI-H

Max data-rate per input 

connection 4 Gbps 2 Gbps

Max aggregate input data rate 4 Gbps 4 Gbps (with 2 PC’s)

Max sustained record rate 4 Gbps 4 Gbps (with 2 PC’s)

RAM buffer size N.A. N.A.

Removable media? Y N

Recording media packaging Mk5 8-disk PATA or SATA 

module RAID array in commercial pkg.

Max # of media packages per 

system

2 N.A.

# media packages for max 

recording data rate 2 2 (with 2 PC’s)

Input data format Any fixed-length Ethernet 

package (e.g. VDIF) VSI-H

Record-data format Ethernet-frame data payload

(typically Mk5B or VDIF) VDIF, K5/VSSP, Mark5B

Media file-system format Proprietary Linux files

Resilient to slow recording 

media? Y Y

Max aggregate playback rate ~1 Gbps Depends on speed of PC

~6 Gbps
67

Playback data interface type GigE 1GigE or 10GigE

Playback data format Same as input format 1GigE or 10GigE

OS type Linux Linux

Software developer

(’proprietary’ or ’open’)

Conduant (prop) and

Haystack (open)

Data Link (prop)

NICT (open)

Command interface 

connection GigE GigE

Command language VSI-S

Direct control by logging into 

the system

Current status Available Available

Cost (USD) ~23K USD ~20K USD

Contact <mark5@haystack.mit.edu> Mamoru Sekido

<sekido@nict.go.jp>

Table 2. Potentially compliant (but not recommended) VGOS Data Recorders.

VLBI Data Recorders that are not VGOS compliant, Table 3a

Mark 5A/B. The Mark 5A recorder was the first entry in the Mark 5 family and as such was designed to 

have minimal disruption from existing tape based systems. Hence it used a VLBA/Mark4 input data 

format and a recorded data-frame format that is based on the VLBA/Mark4 tape systems. The Mark5B 

represents a move towards IVS standards and uses a VSI-H input data format and a Mark 5B data-frame 

format. In both cases, recording media is removable and packaged as Mk5 8-disk PATA or SATA modules 

and the media file-system format is proprietary to Conduant. Mechanically, the Mark 5A/B uses a system 

and disk module enclosure produced by Conduant. Its data electronics include a standard COTS 

motherboard with proprietary disk array interface and data distributor produced by Conduant. Mark 

5A/B data rates are too low to be useful for VGOS and the systems are no longer available.

Mark 5A Mark 5A+ Mark 5B Mark 5B+

 VGOS Compatibility No No No No

Data Input Connection VLBA VLBA VSI-H VSI-H

Max data-rate per input 

connection 1 Gbps 1 Gbps 1 Gbps 2 Gbps

Max aggregate input data 

rate

1 Gbps 1 Gbps 1 Gbps 2 Gbps

Max sustained record rate 1 Gbps 1 Gbps 1 Gbps 2 Gbps

RAM buffer size N.A. N.A. N.A. N.A.

Removable media? Yes Yes Yes Yes

Recording media packaging Mark 5 8-disk PATA or SATA module

Max # of media packages 

per system

2 2 2 2

# media packages for max 

recording data rate 1 1 1 1

Input data format VLBA/Mark 4 VLBA/Mark VSI-H VSI-H
68

Record-data format VLBA/Mark 4 data frame format Mark 5B data frame format

Media file-system format Proprietary (Conduant)

Resilient to slow recording 

media? Yes Yes Yes Yes

Max aggregate playback 

rate

1 Gbps 1 Gbps 1 Gbps 1 Gbps

Playback data interface 

type

GigE GigE GigE GigE

Playback data format VLBA VLBA Mark 5B Mark 5B

OS type Linux Linux Linux Linux

Software developer

(’proprietary’ or ’open’) Conduant (proprietary); Haystack (open)

Command interface 

connection GigE GigE GigE GigE

Command language VSI-S VSI-S VSI-S VSI-S

Current status obsolete obsolete obsolete Obsolete

Cost (USD) N.A. N.A. N.A. N.A.

Contact mark5@haystack.mit.edu

Table 3a. Legacy Mark 5 Data Recorders – not compatible with VGOS and obsolete.

VLBI Data Recorders that are not VGOS compliant, Table 3b.

LBADR. The LBADR is a data recorder designed for the Australian LBA. It uses VSI-H data interfaces and 

Linux files with ’scattered’ data. It is packaged as a Standard PC (with optional disk array) and uses 

standard PC electronics plus a PCI data-capture board from Metsahovi (which is no longer available). 

LBADR data rates are too low to be useful for VGOS.

K5/VSSP32. The K5/VSSP32 is a highly COTS recorder. Its input connection is USB, its file system is linux, 

and it uses a standard COTS PC system with NIC disk interface. It does not support the standard IVS VSI-S 

control protocol but is controlled directly by logging into the system. K5/VSSP32 data rates are too low to 

be useful for VGOS.

LBADR K5/VSSP32

VGOS Compatibility No No

Data Input Connection 2xVSI-H USB

Max data-rate per input 

connection 512 Mbps 256 Mbps

Max aggregate input data rate 512 Mbps 256 Mbps

Max sustained record rate 512 Mbps 256 Mbps

RAM buffer size N.A. N.A.

Removable media? ? Y

Recording media packaging RAID array in commercial pkg. PC removable disk

Max # of media packages per 

system

? Flexible
69

# media packages for max 

recording data rate 1 1

Input data format ? K5-VSSP32

Record-data format ? K5/VSSP *

Media file-system format Linux files w/’scattered’ data Linux files

Resilient to slow recording 

media? Y Y

Max aggregate playback rate ?

Depends on speed of PC

~6 Gbps

Playback data interface type GigE 1GigE or 10GigE

Playback data format VSI-H or optional software 

defined through 1GigE 1GigE or 10GigE

OS type Linux Linux

Software developer

(’proprietary’ or ’open’) ?

Nitsuki (prop)

NICT (open)

Command interface 

connection ? GigE

Command language ?

Direct control by logging into 

the system

Current status PCI data-capture board no 

longer available Available

Cost (USD) N.A. Price of a PC with USB

Contact Chris Phillips

<chris.phillips@csiro.au>

Mamoru Sekido

<sekido@nict.go.jp>

* K5/VSSP Data Format: http://www2.nict.go.jp/aeri/sts/stmg/K5/VSSP/vssp32_format.pdf

Table 3b. Other VLBI Data Recorders – not compatible with VGOS
70

Proposal for VGOS Observing Plan

Bill Petrachenko, Dirk Behrend, Hayo Hase, Chopo Ma, 

Arthur Niell, Axel Nothnagel, Xiuzhong Zhang

February 13, 2014

Over the past several years, VGOS development has been guided by the VLBI2010 

Project Executive Group (V2PEG) and VLBI2010 Committee (V2C) with the V2C 

focusing on completion of the VLBI2010 system and the V2PEG concentrating on 

network expansion. In this document the V2PEG presents an operational plan to bridge 

the gap between the bold targets of VGOS and the current operational programmes of the 

IVS. 

As an initial operational target, VGOS aims for sustained daily product performance at 

the level of the CONT sessions or better by the end of 2017. This represents a daily 

performance improvement that gives the IVS an unambiguous direction for the next four 

years; and it makes clear the IVS’s resolve for a significantly improved VLBI component 

in a tangible time frame. 

This plan provides an operational context for VGOS broadband stations and hence 

motivates both new and legacy stations to seek funds to upgrade to broadband capability. 

It places a priority on early high quality but cost effective daily operations with 

performance improving as operational capacity increases. It assumes that most of the new 

broadband antennas will be dedicated to VGOS operations and will not be shared with 

other applications such as astronomy or spacecraft tracking.

Deployment of VGOS Systems

The VGOS system design is described in detail in the VLBI2010 project specification 

(Petrachenko et al. 2009). Over the past year a number of actions have been undertaken 

in the realization of the concept:

 Broadband feed, digital back end (DBE) and recorder comparisons have been 

completed including information on commercial availability.

 The broadband systems have been improved—specifically towards increased 

reliability and greater compliance with VLBI2010 specifications.

 Geodetic tests have been successfully undertaken (so far only on the GGAO to 

Westford baseline).

 An RFI study was undertaken indicating that: 

o A large number of stations will be able to operate in the full 2–14 GHz 

range without front end saturation.

o A small number of sites will be limited to operating in the 3-14 GHz range 

to avoid front end saturations.

Over the next year it is recommended that the following further steps be encouraged:

 RFI studies continue at potential VGOS sites.
71

 The DORIS/SLR RFI co-location problem is addressed.

 Geodetic broadband observations continue on the GGAO-Westford baseline.

 Broadband observations begin with a third more distant station (e.g. Kokee or 

Wettzell) to demonstrate performance over longer baselines.

 Broadband development continues with the goal of achieving full VLBI2010 

compliance (with commercial availability wherever possible), specifically 

including 

o cryogenic front ends for both QRFH and Eleven Feed.

o DBE’s with 1-GHz bandwidth.

o flexible down converters with full 2–14 GHz.

o completion of high capacity data systems.

o a cable calibration system.

o demonstration of the DBBC3 direct sample system.

o demonstration of a Stirling cycle cryogenic system.

 A convenient and effective ‘mixed-mode’ methodology (i.e., legacy S/X with 

VGOS broadband in S/X mode) needs to be developed so that strong geodetic ties 

can be developed between new VGOS stations and the legacy S/X network.

 Short baseline phase delay measurements be made between new antennas and colocated legacy antennas.

Expansion and Testing of the VGOS Network in 2014

By the end of 2014 as many as eight antennas are expected to have achieved broadband 

capability (see Table 1 and Figure 1).

Table 1. Antennas achieving broadband capability by the end of 2014.

Station When Antenna Notes

GGAO12 Now Fast

Ishioka Mid-2014 Very fast 2 years of S/X/Ka legacy ties

Kokee 2014 Legacy Very fast antenna in 2015

Noto 2014 Legacy Direct sampling approach

Sheshan 2014 Very fast

Westford Now Legacy Shared with Lincoln Laboratory

Wettzell Mid-2014 Very fast

Yebes Mid-2014 Very fast
72

Figure 1. North polar projection of antennas achieving 

broadband capability by the end of 2014.

Throughout 2014 there will be four main VGOS-related activities: 

1. the qualification of new VGOS stations as they come on line in broadband and (if 

RFI permits) S/X modes; 

2. preparations for the VGOS trial operations scheduled for 2015 (see next section 

for details of the trials). Preparations include ensuring that adequate station, media 

and correlator resources are available and that as many processes as possible are 

automated for smooth and sustained operations;

3. the development and testing of processes for mixed-mode (legacy S/X with 

VGOS broadband in S/X mode) operations including the qualification of digital 

back ends at legacy S/X stations; and

4. the execution of mixed-mode sessions (i.e., VGOS broadband stations in S/X 

sessions, e.g., T2, R1, R4) to establish strong ties between legacy and VGOS 

sites.

To help achieve the first two items, the OPC has scheduled seven sessions in 2014 

specifically for VGOS operations. If needed other ad hoc sessions (e.g., for fringe tests) 

can also be added. In order to have a clean spectrum for VGOS broadband observing, the 

VGOS sessions are planned to operate solely in the 3–14 GHz range. The V2PEG 

encourages stations to seek the required funding to join the VGOS sessions of 2014 and 

the VGOS trial operations of 2015. 

For the latter two items it is recognized that RFI around the current S-band frequency 

may preclude the use of a full 2–14 GHz broadband receiver at certain locations, so that 

these broadband stations will not be able to participate in mixed-mode observations. If 

RFI does not inhibit observation at 2–3 GHz, however, broadband conversions and new 

broadband facilities should be encouraged to cover the full 2–14 GHz VGOS range.

Kokee

Ishioka

Sheshan

GGAO12

Westford

Wettzell

Yebes Noto
73

Trial Operations of the VGOS Network in 2015

During 2015 there will be three trial VGOS campaigns to evaluate and improve aspects 

of VGOS operations. To properly assess the sustainability of the three aspects of 

operations, each trial will last at least 6–8 weeks thus ensuring that the full ‘schedule–

acquire–ship/transmit–correlate/process/analyse–ship/transmit’ cycle can be completed 

without developing a back-log. Each trial should further be separated by 8–10 weeks to 

allow for the eventuality of a back-log, to assess performance, to recommend 

improvements, and to prepare for the next trial. This effort will be coordinated by the IVS 

Coordinating Center.

Trial 1: Sustained Weekly 24-hour Sessions, Jan–Feb. This trial involves observing one 

24-hour session each week in VGOS broadband mode. The network will include all 

available qualified VGOS stations, i.e., about 8 stations. Schedules will be optimized to 

best use all VGOS characteristics, in particular the very fast slewing of the new antennas. 

It is recommended that the broadband day be inserted as day 7 (e.g., B7nnn) to best 

bridge the largest gap in the week between R4 and R1 and start at 0 hr UT to match the 

satellite geodetic techniques (see Figure 2). Although an observation on the weekend is 

required, this should not be a problem for a fully qualified VGOS antenna that can safely 

operate in automated or remote control mode. As broadband operations mature, it should 

be possible to record a full 24-hour session on a single recording module. [Given a 

detection limit of SNR=10 per band, a typical source flux distribution and a minimum 

correlated flux of 250 mJy, the average observation at a station should require only about 

10 GB. At 10 GB per observation, a single 32-TB module will record up to 3200 

observations (i.e., 1 observation every 27 s), more than enough to record a full 24-hour 

session on a single module even for “very fast” VGOS antennas.] For sustained 

operations, a pool of four 32-TB modules per station will be required along with funds to 

ship one module per station per week back and forth between the correlator and station.
74

Figure 2. Trial 1: Sustained Weekly 24-hour Session, Jan–Feb. The VGOS Day 7 

(B7nnn) broadband session is represented in red.

Trial 2: Sustained Daily VGOS EOP Sessions, May–June. VGOS broadband 

observations will be carried out on a daily basis using a consistent network. VGOS 

stations that cannot guarantee daily availability because of additional other roles (e.g., 

Noto and Westford) can be added when available on a tag-along basis, which does not 

impact the scheduling of the core network. In recognition of the fact that, at the start of 

VGOS operations, some stations will not have the resources to maintain full 24/7 

observing, this trial involves a reduced duty cycle schedule in which daily sessions are 

made up of four one-hour bursts spaced equally in time, i.e., one burst every six hours 

(see Figure 3). This type of schedule still allows determination of all EOP, strongly 

attenuates diurnal and semi-diurnal signals, and reduces both time variable network 

biases and source selection biases. Aliasing of high frequency EOP due to the gaps 

between bursts in the daily sessions is not expected to be a major negative factor. For this 

type of schedule, all operational costs including data transmission, wear and tear on 

equipment, and power consumption will be equivalent to scarcely more than a single day 

of operations per week. It is assumed that the bursts can be turned on and off in an 

unattended mode so that additional staffing resources will be minimal. The purpose of 

this trial is to exercise sustained daily operations at the stations without regard to timely 

transmission of data to the correlator. Data will be shipped once per week to the 

correlator and will require only a single module per station. Hence the media pool and 

shipping requirements are the same as for Trial 1.

0 

hr

6 

hr

12 

hr

18 

hr

D1 D2 D3 D4 D5 D6 D7

B7

6

R1 R4
75

Figure 3. Trials 2 & 3: Sustained Daily VGOS EOP Sessions, May-June and Sept-Oct. 

Daily hour-long VGOS bursts are represented in red.

Trial 3: Repeat of Sustained Daily VGOS EOP Sessions but with Timely Transmission of 

Data, Sept-Oct. The observations for Trial 2 and Trial 3 are identical (see Figure 3). 

However, the focus of Trial 3 is the timely transport of data to the correlator. As much as 

possible, the data will be transported electronically. With this reduced duty cycle mode of 

operation, a sustained data rate of 500 Mbps will be sufficient to transmit the full 4 hour 

data volume within a day, even for the fastest antennas. For stations where the required 

data rate cannot be sustained, media will need to be physically transported. Daily 

shipment of disk packs only ~15% full is highly inefficient. Efficiency can be increased 

by transferring data to a single disk before shipping. [Note: In the future, as more hours 

of data are collected per day, higher data rates will be required with 3 Gbps being 

sufficient to transmit a full 24 hour session within a day.]

VGOS Pilot Project in 2016

Given the successful completion of the three sets of trial operations, a VGOS Pilot 

Project can begin at the start of 2016 and continue throughout the year. The purpose of a 

pilot project is to gain experience with an operational mode without making a full 

commitment to product delivery. Operations in this period will be a combination of all 

aspects of the trial campaigns. There will be a single 24-hour VGOS session per week 

and daily VGOS EOP sessions on the remaining days (see Figure 4). Data will be 

0 

hr

6 

hr

12 

hr

18 

hr

D1 D2 D3 D4 D5 D6 D7

R1 R4
76

transmitted to the correlator in a timely fashion with as much data transmitted 

electronically as possible.

Figure 4. VGOS Pilot Project: One 24-hour VGOS Session and six Daily VGOS EOP 

Sessions per week, 2016.

As new VGOS stations come on line, they will initially be qualified by tagging along 

with the B7nnn 24-hour sessions. This mode of operation leaves six days a week for the 

newly introduced antenna to deal with problems as they arise. After weekly operations 

smooth out, the antenna can be added to the daily VGOS EOP sessions.

As more operational resources become available at a particular station, the number of 

hour-long burst periods at that station can be increased (Figure 5), providing a smooth 

transition to full 24/7 operation. This can be done on a station-by-station basis, provided 

enough stations are available to form baselines. 

0 

hr

6 

hr

12 

hr

18 

hr

D1 D2 D3 D4 D5 D6 D7

R1 R4 B7
77

Figure 5. As operational resources increase at a station, the number of hourly bursts can 

be increased.

Operations of the VGOS Network in 2017 and Beyond

Given the successful completion of the VGOS Pilot Project in 2016, the pilot project can 

be converted to standard operations.

By the end of 2017, it is anticipated that a substantial VGOS network will be in place 

(first column in Table 2 and Figure 6). Based on information available today, the network 

could include as many as 16 stations, 13 of which will be very fast slewing (full VGOS 

slew rate) antennas. The four Russian antennas will however operate in S/X/Ka-band 

mode. The network will be unbalanced geographically with 15 antennas in the Northern 

Hemisphere, one in the Southern Hemisphere, and a significant concentration in Europe. 

By the end of 2019 the network will be augmented by Ny Ålesund which will be 

operational by then; in the same time frame it is expected that the NASA Space Geodesy 

Project (SGP) will also have constructed a number of new VGOS antennas as part of 

multi-technique GGOS sites (second column in Table 2 and Figure 7). In terms of 

antennas available, the list represents a fairly conservative estimate since it mainly counts 

antenna projects that have already been funded. All the same, it represents a significant 

extrapolation with respect to the number of antennas outfitted with full broadband 

systems. This is an area where the V2PEG needs to participate actively by organizing and 

promoting the acquisition of broadband systems as stations become available. 

0 

hr

6 

hr

12 

hr

18 

hr

D1 D2 D3 D4 D5 D6 D7

R1 R4 B7
78

Station 2017 2019

Yebes 1 1

Santa Maria 1 1

Tenerife 1 1

Flores 1 1

Onsala 2 2

Metsahövi 1 1

Wettzell 2 2

Noto 1 1

Ny Alesund 2

Badary 1

Zelenchukskaya 1

Ussurisk 1

Kaliningrad 1

Kazan ? ?

Ishioka 1 1

Changchun 1 1

Kunming 1 1

Sheshan 1 1

Greenbelt 1 1

Westford 1 1

Kokee 2 2

NASA (new stations) ~3

Total Stations – North Hemisphere 15 23

Hobart 1

Katherine 1

Yarragadee 1

Warkworth 1

Hartebeesthoek 1 1

NASA (new stations) ~2

Total Stations – South Hemisphere 1 7

Total – South and North 16 30

Table 2. Projection of VGOS broadband network that might be available by 2017 and 2019. [Note: As can 

be seen in the table, some stations incorporate more than one broadband antenna. Performance benefits 

are expected at these sites. However, for the purpose of calculating station totals, each pair is considered a 

single station.]
79

Figure 6. Projected VGOS broadband network at the end of 2017. Concentric circles 

represent sites that incorporate two broadband antennas.

Figure 7. Projected VGOS broadband network for the end of 2019. Concentric circles 

represent sites that incorporate two broadband antennas. Cyan dots represent new NASA 

sites hypothetically placed in Colombia, California, and Alaska in the Northern 

Hemisphere and Brazil and Argentina in the Southern Hemisphere.

Petrachenko B et al.(2009): Design Aspects of the VLBI2010 System. Progress Report of 

the VLBI2010 Committee. NASA Technical Memorandum NASA/TM-2009-214180.

North Polar Projection South Polar Projection

North Polar 

Projection

South Polar 

Projection

IVS Coordination

Coordinating Center Report

Dirk Behrend

Abstract This report summarizes the activities of the

IVS Coordinating Center during the year 2013 and

forecasts activities planned for the year 2014.

1 Coordinating Center Operation

The IVS Coordinating Center is based at the Goddard Space Flight Center and is operated by NEOS

(National Earth Orientation Service), a joint effort for

VLBI by the U.S. Naval Observatory and the NASA

Goddard Space Flight Center.

The mission of the Coordinating Center is to

provide communications and information for the IVS

community and the greater scientific community and

to coordinate the day-to-day and long-term activities

of IVS.

The Web server for the Coordinating Center is provided by Goddard. The address is

http://ivscc.gsfc.nasa.gov.

2 Activities during 2013

During the period from January through December

2013, the Coordinating Center supported the following

IVS activities:

• Directing Board support: Coordinated, with local

committees, two IVS Directing Board meetings, in

NVI, Inc.

Coordinating Center

IVS 2013 Annual Report

Metsahovi, Finland (March 2013) and Potsdam,  ̈

Germany (September 2013). Notes from each

meeting were published on the IVS Web site.

• Meetings: Coordinated, with the Local Committee,

the seventh IVS Technical Operations Workshop,

held at Haystack Observatory in May 2013.

Chaired the Program Committee for the meeting.

Technical Operations Workshop

MIT Haystack Observatory

6-9 May 2013

I

zVzSTOW20z 1z 3z

Fig. 1 Logo of the seventh IVS Technical Operations Workshop.

Coordinated, with the Local Committee, the eighth

IVS General Meeting, to be held in Shanghai,

China in March 2014. Chaired the Program

Committee for the meeting.

• Communications support: Maintained the Web

pages, e-mail lists, and Web-based mail archive

files. Generated analysis reports and included them

into the 24-hour session Web pages. Maintained

Intensive session Web pages.

83
84 Behrend

• Publications: Published the 2012 Annual Report in

summer 2013. Published three editions of the IVS

Newsletter in April, August, and December 2013.

All publications are available electronically as well

as in print form.

• Observing Program Committee (OPC): Coordinated meetings of the OPC to monitor the

observing program, review problems and issues,

and discuss changes.

• 2013 Master Schedule: Generated and maintained

the master observing schedule for 2013. Coordinated VLBI resources for observing time, correlator usage, and disk modules. Coordinated the usage

of Mark 5 systems at IVS stations and efficient deployment of disk modules.

• 2014 Master Schedule: Generated the proposed

master schedule for 2014 and received approval

from the Observing Program Committee.

• VGOS: Supported the activities for establishing

the VLBI Global Observing System (VGOS)

through participation in the VLBI2010 Committee

(V2C) and the VLBI2010 Project Executive Group

(V2PEG).

3 CONT14 Campaign

The Continuous VLBI Campaign 2014 (CONT14) is

being organized for observation in early May 2014.

Sixteen IVS stations (see Figure 2) will observe for 15

consecutive days at a rate of 512 Mbps from 6 - 20

May 2014. The observing will be done on the basis of

UT days with each CONT14 day running from 0 UT to

24 UT. UT day observing will allow for the most accurate combination and comparison of results with other

techniques.

The Coordinating Center, in collaboration with the

OPC, is responsible for:

• the overall planning and coordination of the campaign,

• the media usage and shipment schedule, and

• the preparation of the detailed observing schedules

and notes.

More information about the CONT14 campaign

can be found on the IVS Web site under the URL

http://ivscc.gsfc.nasa.gov/program/

cont14.

BADARY 

FORTLEZA 

HART15M

HOBART12 

KATH12M 

KOKEE 

MATERA

NYALES20 

ONSALA60 

TSUKUB32 

WARK12M 

WESTFORD WETTZELL 

YARRA12M 

YEBES40M 

ZELENCHK 

Fig. 2 Geographical distribution of the sixteen CONT14 sites.

4 Staff

The staff of the Coordinating Center is drawn from individuals who work at Goddard. The staff and their responsibilities are listed in Table 1.

Table 1 IVS Coordinating Center staff.

Name Title Responsibilities

Dirk

Behrend

Director Web site and e-mail system maintenance,

Directing Board support, meetings, publications, session Web page monitoring

Cynthia

Thomas

Operation

Manager

Master schedules (current year), resource

management and monitoring, meeting

and travel support, special sessions

Frank

Gomez

Web

Manager

Web server administration, mail system

maintenance, Data Center support, session processing scripts, mirror site liaison

Karen

Baver

General

Programmer

and Editor

Publication processing programs, LaTeX

support and editing, session Web page

support and scripts

Kyla

Armstrong

Data TechnicianPublications support and Web site support

5 Plans for 2014

The Coordinating Center plans for 2014 include the

following:

• Maintain IVS Web site and e-mail system.

• Publish the 2013 Annual Report (this volume).

IVS 2013 Annual Report
Coordinating Center Report 85

• Coordinate, with the local committee, the eighth

IVS General Meeting to be held in Shanghai, China

in March 2014.

• Support Directing Board meetings in 2014.

• Coordinate the 2014 master observing schedules

and IVS resources.

• Publish Newsletter issues in April, August, and December.

• Support the VGOS activities within the V2C and

the V2PEG.

IVS 2013 Annual Report
The 2013 Analysis Coordinator Report

John Gipson

Abstract This report presents the IVS Analysis Coordination issues of 2013. The IVS Analysis Coordinator

is responsible for generating and disseminating the official IVS products. This requires consistency of the input data by strict adherence to models and conventions.

1 Changing of the Guard

In September 2012, Axel Nothnagel gave notice to the

IVS Directing Board that he was resigning as the IVS

Analysis Coordinator effective February 2013. Axel

had been the Analysis Coordinator for 13 years. During this time, the IVS matured from a young, untried

organization into a mature organization providing scientific data for use by geodesists and geophysicists.

His contributions as Analysis Coordinator were many.

The annual IVS Analysis Workshops were an important way for different groups to exchange information

and to advance the VLBI technique. Axel’s insistence

on consistency of models used in different software

packages, adherence to the IERS standards, and continual improvement in geophysical modeling resulted

in high-quality VLBI data. Fortunately Axel is not going away; instead he took a position with more responsibility. At the IVS Directing Board meeting on March

8, 2014, Axel was elected chair of the IVS Directing

Board, and I was elected Analysis Coordinator. I will

endeavor to be as successful an Analysis Coordinator

as Axel.

NVI, Inc./GSFC

IVS Analysis Coordinator

IVS 2013 Annual Report

2 IVS Analysis Workshop

Axel’s last role as Analysis Coordinator was to chair

the “14th IVS Analysis Workshop” held in Helsinki,

Finland on Tuesday, March 5, 2013. As always, this

workshop provided an informal means for everyone

involved in VLBI data processing and analysis to exchange information, voice concerns, and decide how to

proceed.

One of the items that surfaced at this meeting

was the apparent reversal of time-tags in some recent

databases. Explicitly, you would have a situation

where two Scans A and B appear in this order in

the schedule file, with Scan B starting after Scan A.

However, the observations for Scan B had a time tag

in the database before Scan A. Further investigation

revealed that this only happened with databases that

were processed using the DiFX software correlator.

This was ultimately traced to the way the DiFX

software correlators were handling time-tags; the

epoch assigned to all observations in a scan was

halfway through the longest observation in the scan.

In contrast, the Mark IV correlator used a time-tag

which was halfway through the shortest observation

in the scan. Roger Cappallo agreed to modify the

software difx2mk4 that converted correlator output

into a format that could be read by fourfit. That would

make the time-tags consistent with the old hardware

correlator. Alessandra Bertarini agreed to reprocess

some databases using the new time-tags. When these

were analyzed using Calc/Solve, the Goddard VLBI

group found a slight improvement in session fit. As

a consequence of this, all sessions processed after

mid-2013 with DiFX use the same time-tag convention

as the Mark IV hardware correlator.

86
Analysis Coordinator Report 87

The above paragraph is a perfect example of how

the IVS Analysis Workshop should run. An issue is

raised and discussed. People volunteer to do some

work. After further discussion and feedback the VLBI

techhique is improved. I hope to encourage this sort of

activity in future Analysis Workshops.

3 ITRF2013

In March 2013, Zuheir Altamini issued a call for participation in ITRF2013 made by Altamini. The last ITRF

was generated in 2008. A major difference between

the ITRF2008 and the ITRF2013 call for participation

was the introduction of changes to the IERS standards.

The new IERS standards have better models for highfrequency EOP, UT1 in particular. These include the

effects of libration in UT1. The IERS2010 standards

also have a different nutation model.

An area of controversy in generating solutions for

ITRF2013 is the application of atmospheric pressure

loading corrections. VLBI has been a leader in applying atmosphere loading effects, first using local pressure data in the early 1990s to develop empirical loading corrections [1] and then using numerical weather

models to determine the a priori loading at a site [2].

In principal there are two ways of applying pressure

loading corrections. You could determine the a priori

pressure loading corrections at the epoch of the observations and apply them at the observation level. Alternately, you could determine the average pressure loading for a station and apply it a posteriori, after the analysis was done. As [3] shows, there are many arguments

that applying a priori pressure loading at the observation level is the correct thing to do. This is exactly what

the current generation of VLBI analysis packages does.

It was the strong desire of the IVS Directing Board

that the VLBI contribution to ITRF2013 include atmosphere pressure loading effects at the observation

level; however GPS does not do so. After extended conversations with Zuheir, I decided to recommend that

the VLBI solutions also not apply a priori atmosphere

pressure loading. One reason for not doing so was to

makes it easier for Zuheir to combine results. If VLBI

had applied a priori pressure loading, Zuheir would

have had to remove the effect of pressure loading using the a posteriori correction before he combined our

VLBI results with those of other techniques. By not

including the effect of atmosphere pressure loading at

the observation level, we reduce the chance that errors

would be made in removing it.

In preparation for the VLBI solution to ITRF2013

I wrote submission instructions and a submission

checklist. I drew upon instructions that Axel had sent

out for ITRF2008. Unlike ITRF2008, I asked Analysis

Centers to submit their solutions to the IVS Data

Centers. That way all of the data submitted is publicly

available. Frank Gomez at GSFC wrote and debugged

scripts to handle the submissions. Karen Baver, also

at GSFC, helped to design an ITRF2013 web page,

http://lupus.gsfc.nasa.gov/IVS-AC ITRF2013.htm

which gathers all information related to VLBI

submissions for ITRF2013.

4 Analysis Coordinator Web Pages

One of the first things I did as Analysis Coordinator

was, together with Karen Baver, to design a set of IVS

Analysis Coordinator Web pages, accessible through

http://lupus.gsfc.nasa.gov/IVS-AC contact.htm. Our

starting point was the excellent AC Web site of Axel

Nothnagel. My long term goal for these pages is to

gather all VLBI data required or useful for VLBI

solutions. Examples include information about the

sources, stations, etc, as well as links to other sites,

for example the IERS. If there is information that you

think should be on this page, please let me know.

5 Conclusions

At the end of 2013, I completed my first ten months

as the Analysis Coordinator, and I still have much to

learn. This is a position with a lot of responsibility —

both within IVS and outside of IVS. One goal is to

promote the advancement of the VLBI technique with

the IVS — making sure that we use the best models,

making sure that our data is of high quality, and encouraging new ways of doing things. Another goal is

to promote the use of VLBI data to the broader scientific community. This is an impossible task for one person to do alone, and I am aided in this by people both

within Goddard and within the wider IVS community.

IVS 2013 Annual Report
88 Gipson

I welcome your support and suggestions on how I can

do things better.

References

1. MacMillan, D. S. and J. M. Gipson, Atmospheric Pressure

Loading Parameters from Very Long Baseline Interferometric Observations. J.Geophys. Res., 99, 1994. pp. 18,081.

2. Petrov L., J. P. Boy, Study of the Atmospheric Pressure

Loading Signal in VLBI Observations, Journal of Geophysical Research Vol. 109, No. B03405, 2004.

3. Bohm, J., Heinkelmann, R., Cerveira, P., Pany, A., Schuh, H.  ̈

Atmospheric Loading Corrections at the Observation Level

in VLBI Analysis. Journal of Geodesy, 2009, 83: 1107-

1113.

IVS 2013 Annual Report
Network Coordinator Report

Ed Himwich, Rich Strand

Abstract This report includes an assessment of the

network performance in terms of lost observing time

for the 2013 calendar year. Overall, the observing time

loss was about 16.2%, which is about 4% higher than

the previous year due primarily to scheduled antenna

maintenance. A table of relative incidence of problems

with various subsystems is presented. The most significant identified causes of loss were the scheduled antenna maintenance (accounting for about 40% of the

losses), followed by electronics rack problems (20%),

miscellaneous problems (9%), receiver problems (8%),

and RFI (6%). About 6% of the losses occurred for unknown reasons. New antennas are under development

in the USA, Germany, and Spain. There are plans for

new telescopes in Norway and Sweden. Other activities

of the Network Coordinator are summarized.

1 Network Performance

The overall network performance was for the most part

good. As was the case last year, we have returned to reporting a detailed assessment, which was not provided

for 2010 and 2011.

This network performance report is based on correlator reports for experiments in calendar year 2013.

This report includes results for the 159 24-hour experiments that had detailed correlator reports available as

of March 4, 2014. The data set examined includes approximately 515,000 dual frequency observations. ReNASA Goddard Space Flight Center

IVS Network Coordinator

IVS 2013 Annual Report

sults for 29 experiments were omitted because either

they were correlated at the VLBA, they were not correlated yet, or correlation reports were not available

on the IVS data centers. Experiments processed at the

VLBA correlator were omitted because the information provided for them is not as detailed as that from

Mark IV correlators. The experiments that were not

correlated or did not have correlator reports available

yet include some JADE, CRF, APSG, AUST13, OHIG,

R&D, T2, and EUR experiments. In summary, roughly

90% of the data from scheduled 24-hour experiments

for 2013 are included in this report. That is similar to

the coverage of reports for many previous years.

An important point to understand is that in this

report, the network performance is expressed in terms

of lost observing time. This is straightforward in

cases where the loss occurred because operations

were interrupted or missed. However, in other cases,

it is more complicated to calculate. To handle this, a

non-observing time loss is typically converted into an

equivalent lost observing time by expressing it as an

approximate equivalent number of recorded bits lost.

As an example, a warm receiver will greatly reduce the

sensitivity of a telescope. The resulting performance

will be in some sense equivalent to the station having

a cold receiver but observing for (typically) only onethird of the nominal time and therefore recording the

equivalent of only one-third of the expected bits. In a

similar fashion, poor pointing can be converted into an

equivalent lost sensitivity and then equivalent fraction

of lost bits. Poor recordings are simply expressed as

the fraction of total recorded bits lost.

Using correlator reports, an attempt was made to

determine how much observing time was lost at each

station and why. This was not always straightforward

to do. Sometimes the correlator notes do not indicate

89
90 Himwich and Strand

that a station had a particular problem, while the quality code summary indicates a significant loss. Reconstructing which station or stations had problems—and

why—in these circumstances does not always yield accurate results. Another problem was that it is hard to

determine how much RFI affected the data, unless one

or more channels were removed and that eliminated the

problem. It can also be difficult to distinguish between

BBC and RFI problems. For individual station days,

the results should probably not be assumed to be accurate at better than the 5% level.

The results here should not be viewed as an absolute evaluation of the quality of each station’s performance. As mentioned above, the results themselves

are only approximate. In addition, some problems such

as weather and power failures are beyond the control

of the station. Instead the results should be viewed in

aggregate as an overall evaluation of what percentage

of the observing time the network is collecting data

successfully. Development of the overall result is organized around individual station performance, but the

results for individual stations do not necessarily reflect

the quality of operations at that station.

Since stations typically observe with more than one

other station at a time, the average lost observing time

per station is not equal to the overall average loss of

VLBI data. Under some simplifying assumptions, the

average loss of VLBI data is roughly twice the average

loss of station observing time. This approximation is

described in the Network Coordinator’s section of the

IVS 2001 Annual Report. For 2013, this agrees reasonably well with the number of (single frequency: S or X)

single baseline observations on which the correlator reported failure, approximately 36%, but other factors,

particularly the dual frequency nature of useful geodetic observations, complicate the picture. For 2013, the

actual percentage of data (dual frequency) that was not

included by the analysts was approximately 41%. This

is even larger (by approximately 5%) than the single

baseline observations reported lost by the correlator.

It is expected that this number should be higher both

because of the dual frequency nature of the final observable and the fact that analysts use additional criteria beyond what is discussed here to decide when to

exclude observations. However, it means in effect that

only about 59% of the observations we attempted to

collect were useful.

For the 159 experiments from 2013 examined here,

there were 1,432 station days or approximately 9.0 stations per experiment on average. This compares to 148

experiments considered in the report for 2011, which

included 1,261 station days with 8.5 stations per experiment. The increase in the number of analyzed experiments mostly reflects the increase in the number of experiments from 2013. The increase in the average number of stations per experiment is due to the scheduling

of large networks in experiments. Of the station days

for 2013, approximately 16.2% (or approximately 231

days) of the observing time was lost, which is about 4%

higher than last year. For comparison to reports from

earlier years, please see Table 1.

Table 1 Lost observing time.

Year Percentage

1999-2000* 11.8

2001 11.6

2002 12.2

2003 14.4

2004 12.5

2005 14.4

2006 13.6

2007 11.4

2008 15.1

2009 21.5

2012 12.3

2013 16.2

* The percentage applies to a subset

of the 1999-2000 experiments.

Percentages for 2010 and 2011 are

omitted but should be 10-20%.

The lost observing time for 2013 is in line with results from 2012 and years before 2009. The results for

2009 may be artificially high due to a change in the

way the results were tabulated for that year. We believe

this year’s calculations are more in line with how they

were made before 2009.

An assessment of each station’s performance is not

provided in this report. While individual station information was presented in some previous years, this

practice seemed to be counter-productive. Although

many caveats were provided to discourage people from

assigning too much significance to the results, there

was feedback that suggested that the results were being

over-interpreted. Additionally, some stations reported

that their funding could be placed in jeopardy if their

performance appeared bad, even if it was for reasons

beyond their control. Last and least, there seemed to

IVS 2013 Annual Report
Network Coordinator Report 91

be some interest in attempting to “game” the analysis methods to apparently improve individual station

results. Consequently, only summary results are presented here. Detailed results are presented to the IVS

Directing Board. Each station can receive the results

for their station by contacting the Network Coordinator (Ed.Himwich@nasa.gov).

For the purposes of this report, the stations were

divided into two categories: large N: those that were

included in 25 or more network experiments among

those analyzed here and small N: those in 16 or fewer

(no stations were in the 17-24 experiment range). The

distinction between these two groups was made on the

assumption that the results would be more meaningful for the stations with more experiments. The average observing time loss from the large N group was

much smaller than the average from the small N group,

14.6% versus 26.0%. There are many more station days

in the large N group than the small N group, 1,306 versus 161, so the large N group is dominant in determining the overall performance.

There are 22 stations in the large N group. Ten

stations observed in 50 or more experiments. Of the

22 stations, 13 successfully collected data for approximately 90% or more of their expected observing time.

Four more stations collected 80% or more of the time.

Four more stations collected data about 70% or more

of the time. The remaining stations collected data for

about 42% of their observing time. These results are

not significantly different from previous years.

There are 24 stations in the small N group. The

range of lost observing time for stations in this category was 0%-100%. The median loss rate was approximately 15%, a little worse than last year.

The losses were also analyzed by sub-system

for each station. Individual stations can contact the

Network Coordinator (Ed.Himwich@nasa.gov) for

the sub-system breakdown (and overall loss) for

their station. A summary of the losses by sub-system

(category) for the entire network is presented in Table

2. This table includes results since 2003 sorted by

decreasing loss in 2012.

The categories in Table 2 are rather broad and require some explanation, which is given below.

Antenna This category includes all antenna problems, including mis-pointing, antenna control computer failures, non-operation due to wind, and mechanical breakdowns of the antenna. It also includes

scheduled antenna maintenance.

Clock This category includes situations where correlation was impossible because the clock offset either was not provided or was wrong, leading to “no

fringes”. Maser problems and coherence problems

that could be attributed to the Maser were also included in this category. Phase instabilities reported

for Kokee were included in this category. DBBC

clock errors are included in this category.

Miscellaneous This category includes several small

problems that do not fit into other categories, mostly

problems beyond the control of the stations, such as

power (only prior to 2012), (non-wind) weather, cables, scheduling conflicts at the stations, and errors

in the observing schedule provided by the Operation Centers. For 2006 and 2007, this category also

includes errors due to tape operations at the stations

that were forced to use tape because either they did

not have a disk recording system or they did not

have enough media. All tape operations have since

ceased. This category is dominated by weather and

scheduling conflict issues.

Operations This category includes all operational errors, such as DRUDG-ing the wrong schedule, starting late because of shift problems, operator (as opposed to equipment) problems changing recording

media, and other problems.

Power This category includes data lost due to power

failures at the sites. Prior to 2012, losses due to

power failures were included in the Miscellaneous

category.

Rack This category includes all failures that could be

attributed to the rack (DAS), including the formatter

and BBCs. There is some difficulty in distinguishing

BBC and RFI problems in the correlator reports, so

some losses are probably mis-assigned between the

Rack category and the RFI category.

Receiver This category includes all problems related

to the receiver, including outright failure, loss of

sensitivity because the cryogenics failed, design

problems that impact the sensitivity, LO failure, and

loss of coherence that was due to LO problems. In

addition, for lack of a more clearly accurate choice,

loss of sensitivity due to upper X-band Tsys and

roll-off problems were assigned to this category.

Recorder This category includes problems associated with data recording systems. Starting with

IVS 2013 Annual Report
92 Himwich and Strand

Table 2 Percentage of observing time lost by sub-system.

Sub-System 2013 2012 2009 2008 2007 2006 2005 2004 2003

Antenna 39.6 18.1 29.4 19.2 34.6 19.0 24.4 32.9 17.8

Rack 19.5 21.8 6.6 8.7 11.4 16.3 5.1 6.8 5.0

Miscellaneous 9.4 6.9 15.3 12.8 7.6 18.0 8.0 8.0 6.0

Receiver 7.7 11.7 18.6 13.8 14.9 20.8 24.2 18.0 25.2

RFI 6.4 11.8 5.9 14.8 10.4 11.6 6.2 5.0 9.3

Unknown 5.7 14.2 14.2 17.7 14.9 4.0 3.3 10.1 12.6

Clock 3.5 1.8 1.9 0.5 0.3 4.9 14.5 0.5 3.4

Recorder 3.3 5.7 2.9 4.1 4.6 3.3 8.9 11.1 10.9

Operations 2.5 2.0 1.2 2.3 0.0 2.0 4.7 6.1 3.6

Software 1.0 0.3 0.1 0.1 0.4 0.1 0.5 0.1 0.1

Shipping 0.9 3.6 4.0 5.4 1.0 0.0 0.2 1.4 6.1

Power 0.4 2.1

Percentages for 2010 and 2011 were not calculated.

2006, no problems associated with tape operations

are included in this category.

RFI This category includes all losses directly

attributable to interference, including all cases

of amplitude variations in individual channels,

particularly at S-band. There is some difficulty

in distinguishing BBC and RFI problems in the

correlator reports, so some losses are probably

mis-assigned between the Rack category and the

RFI category.

Shipping This category includes all observing time

lost because the media were lost in shipping or held

up in customs or because problems with electronic

transfer prevented the data from being correlated

with the rest of the experiment’s data.

Software This category includes all instances of software problems causing observing time to be lost.

This includes crashes of the Field System, crashes

of the local station software, and errors in files generated by DRUDG.

Unknown This category is a special category for

cases where the correlator did not state the cause

of the loss and it was not possible to determine the

cause with a reasonable amount of effort.

Some detailed comments on the most significant issues for this year’s data loss are given below.

• The largest source of data loss for 2013 was antenna related at 39.6%, up from 18.1% last year.

This includes losses for antennas that were down

for scheduled maintenance, particularly Tsukuba

and Wettzell, which account for about 80% of the

loss in this category. Both observatories are used in

the R1 and R4 experiments each week. The losses

due to these two scheduled maintenance periods account for most of the increase in this category from

last year and most of the increase in the overall loss

for the whole network.

• The data rack was the next largest source of loss at

19.5%, about the same as last year. This loss was

usually caused by missing channels due to broken

converters or samplers. Many were repaired this

year after it was undertaken to bring all stations up

to all 14 working converters. The increased availability of spare parts for old systems as stations

make the switch to digital back-ends helped complete this project. AuScope and Warkworth contributed data rack loss caused by the DBBC. Early

reports for 2014 indicate these systems are now stable.

• The Miscellaneous category is a little higher at

9.4% from 6.9% in 2012 due primarily to Westford’s use for broadband testing of the new VGOS

system. This added 12 station days of loss for 2013.

• Receiver problems contributed about 7.7% to the

overall loss. The was mostly due to cryogenics issues at Fortaleza, which have since been repaired.

• RFI contributed about 6.4% — down from 11.8%

of station days loss — almost all in S-band due

to commercial systems. The stations with the most

significant RFI losses are Fortaleza, Medicina, and

Matera.

• The proportion of losses attributed to Unknown,

RFI, and Receiver decreased this year, primarily because of improvements in classifying the cause of

losses

IVS 2013 Annual Report
Network Coordinator Report 93

Overall, while the network operated well for the

most part, there are a few notable issues (in alphabetical order of station), while some situations improved

from the previous year:

• Crimea had a problem related to a previous repair

of a sampler. This caused the lower four channels of

X-band to be lost in 2013. The problem was found

and repaired.

• Fortaleza had a significant cryogenic problem,

which has since been repaired.

• Hobart12 and Hobart26 have a new and serious RFI

issue.

• Hobart, Katherine, and Yarragadee timing issues

in the DBBCs have improved due to local maintenance work including improved grounding.

• Kokee Park had a power outage that caused some

damage that was difficult to repair. The station was

able to observe with somewhat reduced sensitivity

until the repair was completed.

• Matera’s Mark 5 samplers for S-band channels 5

and 6 were repaired. A rare and intermittent unidentified loss of fringes from 2012 and 2013 were diagnosed in 2014 as being due to the first LO unlocking and re-locking at the wrong frequency due

to a power supply issue. This has been repaired.

• The cryogenic system in the receiver at Medicina

was repaired on September 2013 (after initially failing in November 2011). The station is now able to

observe with normal sensitivity.

• TIGO has shown higher than normal SEFDs for

several years. There has been no success in resolving this issue.

• The Tskuba32 telescope underwent scheduled antenna maintenance for a period of several weeks.

• Warkworth lost a few station days due to a maser

failure.

• The Westford azimuth antenna drives continue to

trip off sometimes when the site is unattended.

They also lost several days supporting broadband

testing and a few days for a maser failure.

• The Wettzell telescope underwent scheduled antenna maintenance for a period of several weeks.

• Yarragadee lost several days due to a filter problem

in their DBBC. This has been repaired.

2 New Stations

There are prospects for new stations on several fronts.

These include (in approximate order of how soon they

will start regular observations):

• At Wettzell in Germany, the new Twin Telescope

Wettzell (TTW) for VGOS has been commissioned.

• At GSFC in the USA, a new 12-m antenna has been

erected and is undergoing testing. While this antenna is primarily for use in the development of the

VGOS system, it is expected that it will eventually

join the network for regular observing.

• South Korea has a new antenna for geodesy at Sejong, built by the National Geographic Information

Institute (NGII). There is also interest in geodetic

use of the Korean VLBI Network (KVN), which

consists of three stations intended primarily for astronomy.

• At Arecibo in Puerto Rico, a new 12-m antenna has

been erected and is expected to be used for geodetic

observing.

• In Spain/Portugal, the RAEGE (Atlantic Network

of Geodynamical and Space Stations) project aims

to establish a network of four fundamental geodetic

stations including radio telescopes that will fulfill

the VGOS specifications: Yebes (1), Canary Islands

(1), and Azores (2).

• In Norway, the Norwegian Mapping Authority

(NMA) is in the process of procuring a twin

telescope.

• Onsala has applied for funds for a twin telescope

system.

• In Russia, an effort is underway to get 12-m VGOS

antennas at some of the QUASAR network sites.

• There is interest in India in building a network of

four telescopes that would be useful for geodesy.

• Saudi Arabia is investigating having a combined

geodetic observatory, which would presumably include a VLBI antenna.

• Colombia is investigating having a combined

geodetic observatory, which would presumably

include a VLBI antenna.

Many of these antennas will become available for

use in the next few years. Efforts are being made to

ensure that these antennas will be compatible with

VGOS.

IVS 2013 Annual Report
94 Himwich and Strand

3 Network Coordination Activities

Network coordination involved dealing with various

network and data issues. These included:

• Reviewing all experiment “ops” messages, correlator reports, and analysis reports for problems and

working with stations to resolve them

• Responding to requests from stations for assistance

• Identifying network station issues and working

with the IVS Coordinating Center and the stations

to resolve them. This year these included:

– Encouraging timely delivery of log files

– Providing a DBBC Validation Plan

– Maintaining the FS PC kernel

• Participating in development of the new VEX2

schedule file standard.

• Providing catalog update information for station

equipment and track lay-outs.

• Recognizing and reporting DBBC issues to station

observing staff.

• Reviewing Mark 5 recording error checks for problems and informing correlator staff and station staff.

• Assisting in troubleshooting the Kokee X-band IF

failure.

• Troubleshooting power supplies and identifying the

correct parts for shipping.

• Troubleshooting video converters and organizing

shipments to stations.

• Providing telescope pointing analysis and advice.

• Support, including software development, for the

12-m antenna at GSFC and VGOS observing system.

4 Future Activities

Network coordination activities are expected to continue next year. The activities will largely be a continuation of the previous year’s activities:

• Reviewing all experiment “ops” messages, correlator reports, and analysis reports for problems and

working with stations to resolve them.

• Responding to requests from stations for assistance.

• Identifying network station issues and working

with the IVS Coordinating Center and the stations

to resolve them.

• Updating Network Station configuration files.

• Helping to coordinate a Mark 5A/5B firmware update for large module directories and bigger disks.

• Helping to plan and support CONT14 observing.

• Providing support, including software development, for the 12-m antenna at GSFC and the VGOS

observing system.

• Other activities as needed.

IVS 2013 Annual Report
IVS Technology Coordinator Report

Bill Petrachenko

Abstract Highlights of IVS technology development

of the past year are summarized. This includes VGOS

technology development, mixed mode observing issues, global VLBI standards, the VGOS technical committee (VTC) and its Wiki, the 2nd International VLBI

Technology Workshop (IVTW), and the IVS Geodetic

VLBI School.

1 VGOS Observing Plan

Over the past year, the VGOS Project Executive Group

(VPEG) developed an observing plan to guide the transition from current S/X to future VGOS broadband operations. The plan spans five years. It begins with a series of test campaigns in 2015 with as many as eight

sites expected to participate. IVS technology development over the next year focuses on ensuring that systems and processes are ready for the test campaigns.

Each campaign introduces a different aspect of the

new VGOS mode of operation so that by 2016 the IVS

will be ready to begin the VGOS pilot project. All campaigns will be roughly six weeks in duration to exercise

the full “schedule to final products” operational chain

in a sustained format.

• The first campaign focuses on automation of processes unique to broadband operations. It uses a

single 24-hour session per week, which has the benefit of allowing six days per week to prepare for the

Canadian Geodetic Survey, Natural Resources Canada

IVS Technology Development Coordinator

IVS 2013 Annual Report

next session. Data will be recorded and shipped after each session.

• The second campaign focuses on producing a full

set of EOP products on a daily basis. It involves

observing four hours per day in equispaced onehour bursts. As with the first campaign, data will

be recorded and shipped once per week.

• The final campaign focuses on producing initial

EOP products within 24 hours. Observationally, it

will be identical to the second campaign but with

the exception that data will be e-transferred instead

of being shipped.

2 VGOS Technology Development

Development of the VGOS broadband system began

in a serious way in about 2008 when the Eleven Feed

was identified as a suitable candidate for use in the next

generation VLBI system. As a result of work carried

out in the subsequent years, the system is now in a useable state although not completely finalized. Several

broadband test sessions were carried out on the ∼600

km Westford to GGAO baseline with the first 24-hour

geodetic session having been carried out in late May

2013.

The new broadband system required nearly a complete reworking of the legacy S/X system including the

frontend, backend, and even the connection between

them. There has been significant progress over the past

year in a number of areas.

95
96 Petrachenko

2.1 Broadband Feeds

It is no surprise that active research into broadband

feeds continues today because it is one of the key

technological innovations that makes the new VGOS

broadband system possible. The workhorse feeds

for the Westford/GGAO broadband baseline are

Quadridge Feed Horns (QRFH) developed at CalTech.

These feeds perform at a high level, are cost effective

and are easy to integrate into cryogenic front ends.

So far they are the only broadband feeds that have

been successfully deployed in a working VGOS

system. Although the QRFH is naturally a dual linear

polarization feed, circular polarization is handled

more naturally by VLBI and is hence preferred. Chris

Beaudoin recently suggested a method for effectively

combining the QRFH linear outputs, post-LNA, into

dual circular outputs. There is also an Auscope/Callisto

collaboration to build a QRFH feed into a cryogenic

system based on a Stirling cycle cooler. This configuration promises to be cost effective, to be very low

maintenance, and to still meet the VGOS SEFD spec

when used with a 12-m antenna.

Work continues on the integration of the Eleven

Feed developed at Chalmers University into a cryogenic front end; a broadband feed developed in Italy

is being tested at Noto, and an innovative conical feed

that naturally produces circular polarized output is being proposed for the Spanish/Portuguese RAEGE antennas.

2.2 Digital-backends (DBEs)

Digital-backend (DBE) development continues in

China, Europe, Japan, Russia, and the United States.

A VLBI Digital-backend Intercomparison Workshop

was conducted at Haystack Observatory in October

2012 to test inter-compatibility between independently

developed DBE units. The results were very positive

showing that in most cases the systems can operate

successfully together.

In addition, to help understand the similarities and

differences between various DBEs, a document named

the VLBI Receiver Back End Comparison, in which

the features of all known DBEs are compared in a table,

was produced. The document can be found on the IVS

Website and the VTC Wiki. Of the DBEs compared,

the ROACH-based DBE (RDBE) and DBBC2010 were

the most applicable to the VGOS system.

Gino Tuccari is prototyping a new cutting edge

DBE system, the DBBC3-H, in which an 8-bit 28 Gsps

digitizer samples the complete VGOS 2-14 GHz RF

spectrum. Unfortunately, the project has been delayed

due to a requirement by the manufacturer that only very

large orders will be filled. To get around this problem,

Gino is looking into the possibility of a joint order with

the the Square Kilometer Array (SKA). In the meantime he is moving forward with a less aggressive broadband sampler, the DBBC3-L, which needs to be coupled with external analog electronics in order to satisfy

VGOS requirements.

2.3 The Mark 6 Data System

The Mark 6 data system is now ready to enter operational service. It is an excellent fit for VGOS. It can

accept data at the VGOS data rate of 16 Gbps, writing

it directly into a 30 s RAM buffer and then moving it

from the buffer to a (single) disk pack at a sustained

rate just under 8 Gbps. With proper care in the development of a schedule it should be easy to ensure that

the buffer is ready to be refilled by the time the VGOS

antenna has slewed to the next source. This mode of operation opens the possibility of writing a complete 24-

hour VGOS session onto a single 32 Tbyte disk pack

that is very efficient for media shipment.

2.4 Delay Calibrator

Phase calibration (PCAL) has always been an important aspect of geodetic VLBI, required both to account

for independent local oscillator (LO) offsets and to

compensate for delay and phase drifts in the system.

It was hoped that the advent of DBEs, with their deterministic linear phase response, would reduce the dependence on PCAL. But for the VGOS broadband system where phase is connected between bands, the need

for PCAL is as great as ever.

A modern PCAL pulse generator has recently been

successfully designed and deployed. However, PCAL

performance is also limited by the stability of the reference signal that drives the pulse generator. The stability

IVS 2013 Annual Report
IVS Technology Coordinator Report 97

of this signal is corrupted by thermal and mechanical

drifts in the cable that connects the hydrogen maser frequency reference to the pulse generator (which is typically located near the receiver frontend). Although it

was initially hoped that a very stable cable could be

found for this purpose, tests over the past year have

shown that the required stability could not be achieved.

As a result, a next generation delay calibrator system is under development at Haystack Observatory.

The principle behind the new system is very similar

to that of the old Mark 3 delay calibrator, although detailed implementation is significantly different. Initial

tests indicate that performance of the new design already nearly meets VGOS requirements.

2.5 Correlator

Although a number of different types of correlators

are currently used for geodetic VLBI, the most commonly used is the DiFX software correlator. DiFX was

originally developed at Swinburne University in Australia by Adam Deller for use in astronomical VLBI.

As its popularity increased, a global DiFX user group

was formed to coordinate continued improvements and

additions. A recent addition is an interface that allows DiFX output to be input to the Mark IV postcorrelation software. This opened the door for the use

of DiFX in geodetic VLBI, and since then DiFX correlators have become operational at the Bonn, Haystack,

and Washington IVS Correlation Centers. Features that

benefit geodetic VLBI continue to be added to DiFX,

but equally important are the additions to the Mark

IV post-correlation software that are needed to handle

VGOS broadband modes. Some noteworthy additions

include: the use of all available PCAL tones to seamlessly connect interferometer phase across the full 2-14

GHz input frequency range; the use of a total electron

content (TEC) search parameter to account for the curvature of phase vs. frequency caused by the ionosphere;

and the addition of the ability to form a pseudo total

intensity observable out of the linear polarized outputs

that are naturally produced by broadband QRFH feeds.

New features continue to be added to both DiFX and

the post correlation software, and these are tested using

data from the Westford/GGAO broadband baseline.

3 Mixed Mode Observing

In order to establish robust geodetic ties between new

broadband stations and the legacy S/X network, a series

of observing sessions that include both broadband and

S/X stations is required. These sessions are referred to

as mixed mode sessions. There is nothing fundamental

that makes these sessions difficult. However, in practice they are complicated by restrictions built into the

details of the systems being used. There are a number

of different types of backends that need to be considered: analog Mark IV; analog VLBA; DBBC in either

digital down converter (DDC) or polyphase filter bank

(PFB) mode; and RDBE in DDC or PFB mode. Beyond

that, S/X stations use a number of different fixed IF

down conversion schemes. This proliferation of backends and down conversion schemes makes compatibility in terms of net LO frequency, sideband, and channel bandwidth difficult to achieve. To help navigate

these issues, a document was prepared entitled Mixed

Mode (Broadband vs. S/X) Configuration Issues. It can

be found on the VTC Wiki. Many of these incompatibilities can be handled in the correlator, but for now

most of the relevant correlator features are not yet fully

tested.

Mixed mode observing also suffers from a sensitivity issue. VGOS broadband antennas are generally

smaller than S/X antennas (which was done to make it

easier for them to achieve high slew rates). For VGOS

observations, this lack of sensitivity is more than compensated by the 16 Gbps instantaneous VGOS data

rate. But when VGOS antennas co-observe with S/X

antennas, data rate is limited to less than 1 Gbps by

the S/X systems. This results in long on-source periods for mixed mode baselines, and this in turn degrades schedules and geodetic performance. The obvious solution is to increase the S/X data rate. However,

this is currently not possible because the analog systems still commonly used at many S/X sites are operationally limited to 8 MHz channel bandwidths which

corresponds to a maximum total data rate of about 1

Gbps. To solve this problem there is currently an effort to decommission analog systems and replace them

with DBEs.

IVS 2013 Annual Report
98 Petrachenko

4 Global VLBI Standards

Over the past decade, the previous IVS Technology

Coordinator, Alan Whitney, did a great service by coordinating the definition of a number of Global VLBI

standards, including VSI-H, VSI-S, VDIF, VDIF2, and

VTP. Most recently it was recognized that VEX, the

pseudo-language that describes the detailed configuration of each station (as well as the schedule of observations), needs to be upgraded to handle new components

that are part of the VGOS system. For obvious reasons,

VEX2, the next generation VEX program, must be in

place before automation of VGOS processes (which in

turn is required to reduce operational costs and hence

enable the VGOS goal of 24/7 operation) can begin.

VEX2 is now nearly complete; its imminent release is

eagerly awaited.

5 The VGOS Technical Committee (VTC)

and its Wiki

The VLBI2010 Committee (V2C), was established in

2006 to encourage the realization of VLBI2010. Over

the years its focus narrowed towards the technical aspects of the next generation system with the following

seven main topic areas identified: system development,

RFI, automation, schedule optimization, source structure, site ties, and the atmosphere. Recently, to reflect

the approaching transition to the operational phase of

the project, the name of the committee was changed to

the VGOS Technical Committee (VTC).

As more VGOS systems are designed and built,

there is an increasing need for communication and

coordination between groups. To serve this purpose,

the VTC established a Wiki that can be found at

https://wikis.mit.edu/confluence/display/VTC/Home.

Wiki contributions related to all VGOS activities are

welcome. Everyone is encouraged to access the wiki

to learn about VGOS developments. But its usefulness

obviously depends on the quality and completeness

of the information on it. So please think about what

documents you have that might be of interest to the

VGOS world. For more information on the Wiki,

please see the related article written by Brian Corey in

the April 2014 issue of the IVS Newsletter.

6 2nd International VLBI Technology

Workshop (IVTW)

The 2nd IVTW was hosted by the Korean Astronomy and Space Science Institute (KASI) at Seogwipo

on Jeju Island, South Korea. The workshop focused

on four topics: station status reports, e-VLBI/Science,

wideband developments, and frequency standards. Attendees at this very well organized workshop were

treated to a field trip to the nearby 21-m Tamna radio

telescope which is an element in the Korean VLBI Network (KVN).

The 3rd IVTW will be held on November 10-13,

2014 at JIVE, Groningen, Netherlands. I encourage

anyone who is interested in VLBI technology to attend this very informative and useful workshop. Strong

representation from the IVS will ensure that geodetic VLBI has a voice in defining a coherent direction

for global multidisciplinary VLBI technology development.

7 Geodetic VLBI School at Altoo

University

On March 2-5, 2013, just prior to the 21st EVGA

Working Meeting, a geodetic VLBI school was held

at Aalto University, Espoo, Finland. The school was

sponsored by the IVS, the EGU, Onsala Observatory,

the Finnish Geodetic Institute, Aalto University, and

RadioNet. It was part of the activities of IVS Working

Group 6, “VLBI Education”, led by Rudiger Haas.  ̈

Lectures and exercises were prepared on a wide

range of topics from Radio Telescopes, Feed Horns,

and Receivers to the Terrestrial Reference Frame. It

was an opportunity for young participants to get a

broad introduction to the field and at the same time

for technology experts to learn about analysis and vice

versa. Since this was the first running of the school,

an important result was the production of learning material on a broad range of topics related to geodetic

VLBI. It was agreed that a school of this type should

be held roughly every three years.

IVS 2013 Annual Report
Network Stations

Badary Radio Astronomical Observatory 2013 IVS Annual Report

Sergey Smolentsev, Valery Olifirov

Abstract This report provides information about the

Badary network station: general information, facilities,

staff, present status, activities during 2013, and outlook.

1 General Information

The Badary Radio Astronomical Observatory (Figure 1) was founded by the Institute of Applied

Astronomy (IAA) as one of three stations of the

Russian VLBI network QUASAR. The sponsoring

organization of the project is the Russian Academy

of Sciences (RAS). The Badary Radio Astronomical

Observatory is situated in the Republic Buryatia

(East Siberia) about 130 km east of Baikal Lake

(see Table 1). The geographic location of the observatory is shown on the IAA RAS Web site

(http://www.ipa.nw.ru/PAGE/rusipa.htm). Basic instruments of the observatory are a 32-m radio telescope

equipped with special technical systems for VLBI

observations, GPS/GLONASS/Galileo receivers, a

DORIS antenna, and an SLR system.

Table 1 Badary Observatory location and address.

Longitude 102◦14′

Latitude 51◦46′

Republic Buryatia

671021, Russia

oper@badary.ipa.stbur.ru

Institute of Applied Astronomy of RAS

Badary Network Station

IVS 2013 Annual Report

Fig. 1 Badary observatory.

2 Technical Staff

Table 2 Staff related to VLBI operations at Badary.

Valery Olifirov observatory chief

Roman Sergeev chief engineer, FS, pointing system control

Roman Kuptsov engineer

Andrey Mikhailov FS, pointing system control

101
102 Smolentsev and Olifirov

3 Component Description

3.1 Technical and Scientific Information

Characteristics of the radio telescope are presented in

Table 3.

Table 3 Technical parameters of the radio telescope.

Year of construction 2005

Mount AZEL

Azimuth range ±270◦(from south)

Elevation range from −5

◦

to 95◦

Maximum azimuth

- velocity 0.83 ◦/s

- tracking velocity 2.5

′

/s

- acceleration 12.0

′

/s

2

Maximum elevation

- velocity 0.5

◦

/s

- tracking velocity 0.8

′

/s

- acceleration 12.0

′

/s

2

Pointing accuracy better than 10′′

Configuration Cassegrain (with

asymmetrical subreflector)

Main reflector diameter 32 m

Subreflector diameter 4 m

Focal length 11.4 m

Main reflector shape quasi-paraboloid

Subreflector shape quasi-hyperboloid

Main reflector surface accuracy ± 0.5 mm

Frequency range 1.4–22 GHz

Axis offset 3.7±2.0 mm

3.2 Co-location of VLBI, GPS/GLONASS,

DORIS, and SLR System

Badary observatory is equipped with the Javad

GPS/GLONASS/Galileo receiver, The SLR system

“Sazhen-TM” (Figure 3), beacon “DORIS”, and

automatic meteorological station WXT-510 are in

operation (Figure 2).

4 Current Status and Activities during

2013

Badary observatory participates in IVS and domestic

VLBI observing programs. During 2013, Badary staFig. 2 Javad GPS/GLONASS/Galileo receiver and beacon

“DORIS” at the Badary observatory.

Fig. 3 “Sazhen-TM” SLR system at Badary observatory observed 1278 passes of Lageos, GLONASS et al. and obtained

11430 normal dots.

tion participated in 31 diurnal IVS sessions — IVS-R4,

IVS-T2, and EURO.

Badary participated in 48 diurnal sessions in the

frame of the domestic Ru-E program for determination

of all Earth orientation parameters and in 191 one-hour

Ru-U sessions for obtaining Universal Time using eVLBI data transfer. Since April 2013 we have used

e-VLBI data transfer for Badary observation data for

Ru-E sessions.

Finally, an antenna tower for the 13.2-m dish was

built.

IVS 2013 Annual Report
Badary IVS Annual Report 103

Fig. 4 Autumn 2013, building in progress.

Fig. 5 Antenna tower for 13.2-m dish.

Fig. 6 Main reflector 13.2-m and antenna tower.

5 Future Plans

Our plans for the coming year are the following:

• To participate in IVS observations including

CONT14 IVS campaign,

• To carry out domestic observing programs for

obtaining Universal Time daily and for obtaining

Earth orientation parameters with e-VLBI data

transfer weekly,

• To carry out SLR observations of geodetic and navigation satellites,

• To participate in EVN and RADIOASTRON observing sessions,

• To continue geodetic monitoring of the RT-32 parameters,

• To install a WVR, and

• To finish VLBI2010 antenna installation in 2014.

References

1. Finkelstein A., Ipatov A., Smolentsev S. The Network

“Quasar”: 2008-2011 // “Measuring the future”, Proc. of the

Fifth IVS General Meeting, A. Finkelstein, D. Behrend (eds.),

St. Petersburg, “Nauka”, 2008. pp. 39–46.

IVS 2013 Annual Report
Effelsberg Radio Observatory 2013 Annual Report

Uwe Bach, Alex Kraus

Abstract The 100-m radio telescope of the MaxPlanck-Institut fur Radioastronomie (MPIfR) is one  ̈

of the two largest fully steerable single-dish radio

telescopes in the world and a unique high-frequency

radio telescope in Europe. The telescope can be used

to observe radio emission from celestial objects in a

wavelength range from 90 cm (∼300 MHz) down to

3.5 mm (∼90 GHz).

1 General Information

The Effelsberg radio telescope was inaugurated in 1971

and was (for almost 30 years) the largest fully steerable single-dish radio telescope in the world. It is situated in a protected valley near Bad Munstereifel (about  ̈

40 km southwest of Bonn) and operated by the MaxPlanck-Institut fur Radioastronomie (MPIfR) on behalf  ̈

of the Max-Planck-Society (MPG). To this day, it is the

largest radio telescope in Europe and is mostly used for

astronomical observations.

The extremely versatile and flexible instrument can

be used to observe radio emission from celestial objects

in a wavelength range from about 1 m (corresponding to a frequency of ∼300 MHz) down to 3.5 mm

(86 GHz). The combination of the high surface accuracy of the reflector (the mean deviation from the ideal

parabolic form is ∼0.5 mm RMS) and the construction

principle of ‘homologous distortion’ (i.e., the reflector

in any tilted position has a parabolic shape with a wellMax-Planck-Institut fur Radioastronomie, Bonn, Germany  ̈

Effelsberg Network Station

IVS 2013 Annual Report

defined, but shifted, focal point) enables very sensitive

observations at high frequencies (i.e., ν >10 GHz).

The wide variety of observations with the 100-m

radio telescope is made possible by the good angular

resolution, the high sensitivity, and a large number of

receivers which are located either in the primary or in

the secondary focus. Together with a number of distinguished backends dedicated to different observing

modes, this provides excellent observing conditions for

spectroscopic observations (atomic and molecular transitions in a wide frequency range), and also for high

time-resolution (pulsar observations), mapping of extended areas of the sky and participation in a number of interferometric networks (mm-VLBI, EVN, and

Global VLBI etc.).

Table 1 Telescope properties.

Name Effelsberg

Coordinates 6:53:01.0 E,+50:31:29.4 N

Mount azimuthal

Telescope type Gregorian (receivers in prime

and secondary focus)

Diameter of main reflector 100 m

Focal length of prime focus 30 m

Focal length of secondary 387.7 m

focus

surface accuracy 0.55 mm RMS

Slew rates Azi: 25 deg/min, Elv: 16 deg/min

Receivers for Geodetic 3.6 cm/13 cm secondaryobservations focus (coaxial)

T sys (3.6 cm/13 cm) 25 K, 200 K

Sensitivity (3.6 cm/13 cm) 1.4 K/Jy, 0.5 K/Jy

HPBW (3.6 cm/13 cm) 81 arcsec, 350 arcsec

104
Effelsberg 2013 Report 105

Fig. 1 Aerial image of the Effelsberg radio observatory. Shown are the 100-m Effelsberg antenna and the institute building. Effelsberg

hosts also a station of the European Low Frequency Array (LOFAR), seen in the lower part of the picture.

2 Activities during the Past Year

About 30% of the observing time of the Effelsberg antenna is used for VLBI observations. Most of them are

astronomical observations for the European VLBI Network (EVN), High Sensitivity Array (HSA), Global

MM VLBI Array (GMVA) or other global networks,

but also geodetic VLBI observations are performed.

Effelsberg has regularly participated in the EUROPE

IVS sessions since 1991. In autumn 2013, the slew

rates of the antenna had to be reduced because of work

at the main power supply of the station. Therefore the

schedule for EUR126 had to be adapted to the slower

speeds.

3 Current Status

Effelsberg is using the DBBC2 and a Mark 5B+

recorder for all EVN, global, and geodetic VLBI

observations. In addition, there are two NRAO RDBEs

and a Mark 5C recorder that are used for observations with the VLBA and HSA. The observatory is

connected via a 10 GE optical fiber to the e-VLBI

network and can do real time e-VLBI observations and

e-transfer of data to Bonn and JIVE.

4 Future Plans

Upgrades for several receiving systems are planned for

2014. In January, a new K-band receiver (18 to 26

GHz) was installed into the secondary focus and is

just being commissioned. The construction of a new

C-band system (4-8/9.3 GHz) for wide band observations and the installation of a new Q-band receiver (38

to 50 GHz) are planned for 2014 as well. The new receivers will provide wide band IF signals of 2.5 GHz

band width which can be used with the next generation of digital VLBI backends and recorders, like the

DBBC3 and Mark 6, to record data at recording rates

of up to 16 Gbps.

IVS 2013 Annual Report
Fortaleza Station 2013 Annual Report

Pierre Kaufmann 1, A. Macilio Pereira de Lucena 2,Adeildo Sombra da Silva 1

Abstract This is a brief report about the activities carried out at the Fortaleza geodetic VLBI station (ROEN:

Radio Observat  ́ orio Espacial do Nordeste), located in  ́

Eusebio, CE, Brazil, during the period from January  ́

until December 2013. The total observed experiments

consisted of 99 VLBI sessions and continuous GPS

monitoring recordings.

1 General Information

The Radio Observat  ́ orio Espacial do Nordeste, ROEN,  ́

located at INPE facilities in Eusebio, nearly 30 km east  ́

of Fortaleza, Ceara State, Brazil, began operations in  ́

1993. Geodetic VLBI and GPS observations are carried out regularly, as contributions to international programs and networks. ROEN is part of the Brazilian

space geodesy program, which was initially conducted

by CRAAE (a consortium of the Brazilian institutions

Mackenzie, INPE, USP, and UNICAMP) in the early

1990’s. The program began with antenna and instrumental facilities erected, with activities sponsored by

the U.S. agency NOAA and the Brazilian Ministry of

Science and Technology’s FINEP agency.

ROEN is currently coordinated by CRAAM,

Center of Radio Astronomy and Astrophysics, Engineering School, Mackenzie Presbyterian University,

Sao Paulo, in agreement with the Brazilian National  ̃

Space Research Institute, INPE. The activities are cur1. Universidade Presbiteriana Mackenzie, CRAAM and INPE,

Radio Observat  ́ orio Espacial do Nordeste, ROEN  ́

2. Instituto Nacional de Pesquisas Espaciais, ROEN

Fortaleza Network station

IVS 2013 Annual Report

rently carried out under an Agreement of Cooperation

signed between NASA—representing research interests of NOAA and USNO—and the Brazilian Space

Agency, AEB, which has been extended until 2021.

Under the auspices of the NASA-AEB Agreement,

a contract was signed between NASA and CRAAM,

Mackenzie Presbyterian Institute and University to

partially support the activities at ROEN.

The counterpart of the operational costs, staff, and

support of infrastructure are provided by INPE and by

Mackenzie.

Fig. 1 14.2-m radio telescope.

106
Fortaleza 2013 Report 107

2 Main Instruments

The largest instrument at ROEN is the 14.2-m radio

telescope, on an alt-azimuth positioner. It is operated at

S- and X-bands, using cryogenic radiometers. The system is controlled by the Field System, version 9.10.4.

Observations are recorded with a Mark 5 system. One

Sigma-Tau hydrogen maser clock standard is operated

at ROEN. GPS monitoring is performed within a cooperative program with NOAA (USA). There is a Leica System 1200 installed at the station that operates

continuously. The collected data are provided to the

NOAA/IGS center and to the Brazilian IBGE center. ROEN has all basic infrastructures for mechanical,

electrical, and electronic maintenance of the facilities.

3 Staff

The Brazilian space geodesy program is coordinated

by one of the authors (PK), who is Brazil’s AEB representative in the NASA-AEB Agreement. The coordination receives support from the Sao Paulo of-  ̃

fice at CRAAM/Instituto and Universidade Presbiteriana Mackenzie, with administrative support from Valdomiro M. S. Pereira and Luc ́ıola Melissa Russi. The

Fortaleza Station facilities and geodetic VLBI and GPS

operations are managed on site by Dr. Antonio Macilio

Pereira de Lucena (INPE), assisted by Eng. Adeildo

Sombra da Silva (Mackenzie), and the technicians Avicena Filho (INPE) and Francisco Renato Holanda de

Abreu (Mackenzie).

4 Current Status and Activities

4.1 VLBI Observations

In the year 2013, Fortaleza station participated in

geodetic VLBI experiments as listed in Table 1.

Most of the recorded data are being transferred to

the correlators through a high speed network from the

Mark 5A recorder unit. The data from the Fortaleza station is uploaded either to the correlators in the U.S.

through FIU (Florida International University) or directly to the Bonn correlator.

Table 1 2013 session participation.

Experiment Number of Sessions

IVS-R1 40

IVS-R4 45

IVS-T2 06

IVS-R&D 01

IVS-RDV 01

IVS-CRF 02

IVS-CRMS 02

IVS-OHIG 04

4.2 Operational and Maintenance

Activities

The summary of activities performed in the period is

listed below:

1) Repair and maintenance of the cryogenic system,

Mark IV video converters, and antenna pointing system;

2) Survey on RFI in S-band;

3) Maintenance and adjustment of DC azimuth and

elevation motors;

4) Operation and maintenance of geodetic GPS

(NOAA within the scope of the NASA contract);

5) Operation and maintenance of power supply

equipment at the observatory (main and diesel driven

standby);

6) Welding at some points of the antenna structure;

7) Maintenance of the Web site and the local server

computer (http://www.roen.inpe.br).

4.3 GPS Operations

The IGS network GPS receiver operated regularly at all

times during 2013. Data were collected and uploaded

to an IGS/NOAA computer.

IVS 2013 Annual Report
Goddard Geophysical and Astronomical Observatory

Ricardo Figueroa, Jay Redmond, Katherine Pazamickas

Abstract This report summarizes the technical parameters and the technical staff of the VLBI system at the

fundamental station GGAO. It also gives an overview

about the VLBI activities during the 2013 report year.

The outlook lists the outstanding tasks to improve the

performance of GGAO.

1 GGAO at Goddard

The Goddard Geophysical and Astronomical Observatory (GGAO) consists of a 5-meter radio telescope for

VLBI, a new 12-meter radio telescope for VLBI2010

development, a 1-meter reference antenna for microwave holography development, an SLR site that

includes MOBLAS-7, the NGSLR development

system, a 48′′ telescope for developmental two-color

Satellite Laser Ranging, a GPS timing and development lab, a DORIS system, meteorological sensors,

and a hydrogen maser. In addition, we are a fiducial

IGS site with several IGS/IGSX receivers.

GGAO is located on the east coast of the United

States in Maryland. It is approximately 15 miles NNE

of Washington, D.C. in Greenbelt, Maryland (Table 1).

NASA Goddard Space Flight Center

GGAO Network Station

IVS 2013 Annual Report

Table 1 Location and addresses of GGAO at Goddard.

Longitude 76.4935◦ W

Latitude 39.0118◦ N

MV3

Code 299.0

Goddard Space Flight Center (GSFC)

Greenbelt, Maryland 20771

http://cddisa.gsfc.nasa.gov/ggao/vlbi.html

2 Technical Parameters of the VLBI Radio

Telescopes at GGAO

The 5-m radio telescope for VLBI at MV3 was originally built as a transportable station; however, it was

moved to GGAO in 1991 and has been used as a fixed

station. In the winter of 2002 the antenna was taken off

its trailer and permanently installed at GGAO.

In October of 2010, construction of the new

12-meter VLBI2010 developmental antenna was completed. This antenna features all-electric drives and a

Cassegrain feed system. Integration of the broadband

receiver and the associated sub-systems is underway

as a joint effort between Exelis and the MIT Haystack

Observatory.

The technical parameters of the radio telescopes are

summarized in Table 2.

3 Technical Staff of the VLBI Facility at

GGAO

GGAO is a NASA R&D and data collection facility.

It is operated under the Space Communication Network Services (SCNS) contract by Exelis Inc. The staff

108
GGAO IVS Report for 2013 109

Fig. 1 Goddard Geophysical and Astronomical Observatory.

Table 2 Technical parameters of the radio telescopes at GGAO.

Parameter 5-m 12-m

Owner and operating agency NASA NASA

Year of construction 1982 2010

Diameter of main reflector d 5−m 12−m

Azimuth range +/−270◦ +/−270◦

Azimuth velocity 3

◦/s 5◦/s

Azimuth acceleration 1

◦/s2 1◦/s2

Elevation range +/−90◦ 5−88◦

Elevation velocity 3

◦/s 1.25◦/s(Avg.)

Elevation acceleration 1

◦/s2 1◦/s2

Receiver System

Focus Cassegrain Cassegrain

Receive Frequency 2−14GHz 2−14GHz

Tsys 100K 50K(T heoretical)

Bandwidth 512MHz, 4 bands 512MHz, 4 bands

G/T 26dB/K 43dB/K

VLBI terminal type CDP VLBI2010

Recording media Mark IV Mark 5C

at GGAO consists mainly of two operators and one

backup engineer. The Exelis staff includes Jay Redmond and Katherine Pazamickas conducting VLBI operations and maintenance at GGAO with the support of

Ricardo Figueroa.

4 Status of MV3 and VLBI2010 at GGAO

Having ceased VLBI operations in May 2007, MV3

continues on a full time basis to be a major component in the program to demonstrate the feasibility of

the VLBI2010 broadband delay concept. Working unIVS 2013 Annual Report
110 Figueroa et al.

der the guidance of the Exelis team, the majority of

MV3’s S/X components have been upgraded, and antenna refurbishing should be completed by early 2014

to provide additional support to the VLBI2010 System. The 2013 accomplishments for the 5-m antenna

include:

• The 017 Electronic Box was refurbished and installed with new wiring and upgraded components.

• The Cryogenic Dewar and the components were restored for X-band operations. Also, the cryogenic

thermometer, vacuum gauge, and bias voltage box

were installed and tested.

• The FSS Subreflector and Feed assembly, including the FSS, was recoated with a highly reflective

surface, repaired, and placed back on the antenna.

• The ACU and control panel are in the process of

upgrade and troubleshooting.

• Two of the Sargent Welch Directorr Model 8816-

B were refurbished using a repair kit. One was

mounted and tested in the antenna.

Much of the 2013 activities at GGAO have been

focused on performance testing and upgrading of the

VLBI2010 12-m antenna. However, there were some

other activities worth noting:

• Installation of the new Broadband self-retractable

feed positioner for the 12-meter antenna. The positioner is controlled remotely to lower the cryogenics and perform receiver maintenance.

• Continuation of wideband system testing and characterization of the 12-m antenna.

• Procurement of new test equipment for characterization of the wideband RF hardware.

• Continuation of Broadband Phase Cal performance

testing.

• Integration of RDBEs, Mark 5Cs, and Field System

computer software.

• Installation of receiver radome.

• VLBI observations between Westford and GGAO

and processing of data.

• Monitoring and Control Interface (MCI) installation and testing. The MCI is currently used for remote cryogenics and electronic status.

• Performance testing of the 16 Gbps VLBI recording, demonstrated using Mark 6.

• Installation of the high frequency optical fiber link

system.

5 Outlook

GGAO will continue to support VLBI2010, e-VLBI,

and other developmental activities during the upcoming year. Tentative plans for 2014 include:

• Continuing to upgrade the VLBI2010 broadband

receiver system on the 12-m antenna.

• Conducting IVS observations using the Mark 5C

and Mark 6 recorders to demonstrate the VLBI2010

capabilities.

• Continuing testing of the new broadband phase calibrator for the VLBI2010 system.

• Continuing the upgrade of the 5-m antenna ACU

and initiating testing of the S/X band.

• Continuing to measure the baseline between the 5-

m and the 12-m antennas for position ties to the

reference frame.

• Trying to understand the source of the azimuth and

elevation gearboxes’ oil contamination.

• Trying to understand why the antenna will not

move in elevation under computer control when

first started up on cold mornings.

IVS 2013 Annual Report
Hartebeesthoek Radio Astronomy Observatory (HartRAO)

Marisa Nickola, Jonathan Quick, Ludwig Combrinck

Abstract HartRAO provides the only fiducial geodetic

site in Africa, and it participates in global networks for

VLBI, GNSS, SLR and DORIS. This report provides

an overview of geodetic VLBI activities at HartRAO

during 2013, including the 15-m radio telescope officially joining geodetic VLBI operations as well as the

funding of the first African VGOS site.

1 Geodetic VLBI at HartRAO

Hartebeesthoek is located 65 km northwest of Johannesburg, just inside the provincial boundary of Gauteng, South Africa. The nearest town, Krugersdorp, is

32 km away. The telescopes are situated in an isolated valley which affords protection from terrestrial

radio frequency interference. HartRAO currently uses

both a 26-meter and a 15-meter radio telescope. The

26-m is an equatorially mounted Cassegrain radio telescope built by Blaw Knox in 1961. The telescope was

part of the NASA deep space tracking network until

1974 when the facility was converted to an astronomical observatory. The 15-m is an alt-az radio telescope

built as a Square Kilometre Array (SKA) prototype

during 2007 and converted to an operational geodetic VLBI antenna during 2012. The telescopes are colocated with an ILRS SLR station (MOBLAS-6), an

IGS GNSS station (HRAO), and an IDS DORIS station (HBMB) at the adjoining South African National

HartRAO

HartRAO Network Station

IVS 2013 Annual Report

Space Agency Earth Observation (SANSA EO) site.

HartRAO is also a full member of the EVN.

Fig. 1 The HartRAO 26 m under repair after a thunderstorm and

lightning strike during the Ultra-rapid R1579 on 2 April 2013

(with the 15 m in the background).

2 Technical Parameters of the 26-m and

15-m Telescopes of HartRAO

Table 1 contains the technical parameters of the HartRAO 26-m and 15-m radio telescopes, while Table 2

and Table 3 contain technical parameters of the HartRAO 26-m and 15-m receivers, respectively. The current data acquisition systems consist of a DBBC terminal and a Mark 5B+ recorder for both the 26 m and the

15 m. A Mark 5B and a Mark 5C recorder are used for

e-transfer of data and conditioning and testing of disk

packs. Three hydrogen masers are available for use,

111
112 Nickola et al.

namely the iMaser 72, which is currently employed for

VLBI on the 26 m, as well as two spares — EFOS-28,

currently employed on the 15 m, and the resuscitated

EFOS-6.

Table 1 Antenna parameters.

Parameter HartRAO Hart15M

Owner and operating agency HartRAO HartRAO

Year of construction 1961 2007

Radio telescope mount Offset equatorial Az-El

Receiving feed Cassegrain Prime focus

Diameter of main reflector d 25.914m 15m

Focal length f 10.886m 7.5m

Focal ratio f /d 0.42 0.5

Surface error of reflector (RMS) 0.5mm 1.6mm

Short wavelength limit 1.3cm 2cm

Pointing resolution 0.001◦ 0.001◦

Pointing repeatability 0.004◦ 0.004◦

Slew rate on each axis HA: 0.5

◦

s

−1 Az: 2◦

s

−1

Dec: 0.5

◦

s

−1 El: 1◦

s

−1

Table 2 26-m receiver parameters (degraded performance due to

dichroic reflector being used for simultaneous S-X VLBI).

Parameter X-band S-band

Feeds dual CP conical dual CP conical

Amplifier type cryo HEMT cryo HEMT

Tsys (K) 52 40

SSEFD (Jy) 849 1190

PSS (Jy/K) 16.3 29.8

3 dB beamwidth (◦) 0.096 0.418

Table 3 15-m co-axial receiver parameters.

Parameter X-band S-band

Feeds stepped horn wide-angle corrugated horn

Amplifier type cryo HEMT cryo HEMT

Tsys (K) 40 42

SSEFD (Jy) 1400 1050

PSS (Jy/K) 35 25

3 dB beamwidth (◦) 0.16 0.57

3 Current Status

The 15 m was operating in test mode at the start of

2013, participating in three Ultra-Rapid sessions with

Tsukuba and Onsala during January and February

2013. One of these sessions, R1573 on 18 February

2013, was run in tag-along mode. The 15 m made

its official debut during another Ultra-rapid session

with Tsukuba and Onsala — R1580 on 8 April 2013.

It joined the 26 m for the first time on 5 August

2013 during the Ultra-rapid, R1597, with Onsala

and Yarragadee. Another seven dual experiments

were performed during the year with the 15-m maser

having to be offset in frequency to prevent PCAL

cross-correlation. R1597 was also to be the first

formal session with HART15M using the DBBC

under FS control. On the 19th of September, the 15

m participated in its first official R4, followed by

another three R4s for 2013, with the last one, R4616

on 19 December 2013, wrapping up 2013 observing

session proceedings at HartRAO. The 15 m also

replaced the 26 m in the penultimate session of the

year adding an RD session to its tally. The 15 m

participated in the AUSTRAL sessions, a Southern

Hemisphere observing program, together with the

AuScope antennas and Warkworth’s 12 m. AUSTRAL

sessions 10-16 were run over a period stretching from

July to November 2013 with a 15-day continuous

AUSTRAL-CONT campaign starting on the 28th of

November and finishing up on 16 December 2013.

All AUSTRALs, and most other sessions in which the

15 m participated, were run under remote control by

Jonathan Quick. During 2013, the 26 m participated in,

amongst others, nine Ultra-rapid sessions (R1/T2/RD)

— seven together with Onsala and Tsukuba and two

with Onsala and Yarragadee. The 26 m switched

to using DBBC and Mark 5B+ in its penultimate

session for 2013, R1616 on the 16th of December.

Geodetic VLBI data for all but the RDV sessions

(excluding those sessions where disk packs failed)

were e-transferred to the correlators. Telescope time

allocation for geodetic VLBI in 2013 consisted of 56

and 37 24-hour experiments for the 26 m and 15 m,

respectively (Table 4). Webcams installed for both

telescopes may be accessed via HartRAO’s webpage.

During September 2013, Ludwig Combrinck installed

a tide gauge on Gough Island. A seismic vault containing a seismometer, gravimeter, and accelerometer has

also been installed on site at HartRAO.

IVS 2013 Annual Report
HartRAO 113

Table 4 Geodetic VLBI experiments in which HartRAO participated during 2013.

Experiment No. of sessions on 26 m No.of sessions on 15 m

R1 25 10

RD 8 1

T2 7 0

CRDS 6 0

CRF 4 0

OHIG 3 0

RDV 3 0

R4 0 4

AUST 0 7

AUST13 0 15

Total 56 37

4 Personnel

Table 5 lists the HartRAO station staff who are

involved in geodetic VLBI. Jonathan Quick (VLBI

friend) provides technical support for the Field System

as well as for hardware problems. Radio astronomer

Alet de Witt attended the VLBI Training School

and the 21st European VLBI for Geodesy and Astrometry (EVGA) Working Meeting held in Espoo,

Finland in March 2013. During this meeting and the

subsequent Journees 2013 “Syst  ́ emes de R ` ef ́ erence  ́

Spatio-Temporels” at the Observatoire de Paris, France

in September 2013, Alet represented HartRAO in the

IAU’s ICRF3 working group. Alet and microwave

engineer Ronnie Myataza participated in the Seventh

IVS Technical Operations Workshop presented at

Haystack Observatory in May 2013. Space Geodesy

student Denise Dale and Marisa Nickola (geodetic

VLBI support) attended the VieVS Fourth User

Workshop in Vienna, Austria during September 2013.

Table 5 Staff supporting geodetic VLBI at HartRAO.

Name Function Program

L. Combrinck Program Geodesy

Leader

J. Quick Hardware/ Astronomy

Software

R. Botha Operator Geodesy

J. Grobler Operator Technical

L. Masongwa Operator Technical

R. Myataza Operator Technical

M. Nickola Logistics/ Geodesy

Operations

P. Stronkhorst Operator Technical

C. Zondi Operator Technical

5 Future Plans

Looking at the preliminary schedule for 2014, the

26-m antenna’s geodetic workload has been reduced

significantly, with only 25 of the 131 sessions allocated

to HartRAO being run on the 26 m. Hart15M will participate in both the CONT14 and AUST14 continuous

campaigns during May 2014 and November/December

2014, respectively. The good news is that funds have

been allocated for the VLBI2010 VGOS antenna. It

is to be built on site, and an appropriate location for

the antenna has already been identified to the north of

the 26 m and the SLR station. With funding for the

VGOS antenna having been allocated over the next

three years (2014-2016), the process of procuring the

antenna is expected to start in 2014. A VGOS site

investigation, including geotechnical and RFI studies,

will be pursued during 2014. A site tie is also planned

for the early part of the year. Work on the Lunar Laser

Ranger (LLR) project will continue during 2014.

HartRAO intends sending a sizeable delegation to

the 8th IVS General Meeting to be held in Shanghai,

China, in early March 2014, in order to put in a bid for

hosting the next IVS General Meeting in 2016. During

this meeting, Alet will once again participate in the

IAU’s ICRF3 working group discussions.

Acknowledgements

HartRAO is a National facility operating under

the auspices of the National Research Foundation

(NRF), South Africa. The Space Geodesy Programme

is an integrated program, combining VLBI, SLR,

and GNSS, and it is active in several collaborative

projects with GSFC, JPL, and GFZ (Potsdam) as

well as numerous local institutes. Collaboration also

includes CNES/GRGS/OCA and the ILRS community in a Lunar Laser Ranger (LLR) project with

local support from the University of Pretoria and

the National Laser Centre (CSIR), among others.

General information as well as news and progress

on geodesy and related activities can be found at

http://geodesy.hartrao.ac.za/.

IVS 2013 Annual Report
114 Nickola et al.

Fig. 2 Ronnie and Lerato in the microwave lab measuring Trec of

the 26 m’s 3.5-cm Dicke switch cryogenically cooled receiver.

Fig. 3 Tsys measurements of the 26-m antenna’s 3.5-cm Dicke

switch cryogenically cooled receiver and feed.

Fig. 4 Ronnie at the entrance to the vault with the 26 m and the

15 m behind him and the SLR and the LLR to his right.

Fig. 5 Ludwig installing a tide gauge on Gough Island in the

South Atlantic Ocean.

Fig. 6 Hardware gecko — luckily these days data are being etransferred.

IVS 2013 Annual Report
AuScope VLBI Project and Hobart 26-m Antenna

Jim Lovell 1, John Dickey 1, Brett Reid 1, Jamie McCallum 1, Stas Shabala 1, Christopher Watson 2, Lucia

Plank 1, Simon Ellingsen 1, Anthony Memin 1

Abstract This is a report on the activities carried out at

the University of Tasmania in support of the three AuScope VLBI observatories and the Hobart 26-m antenna.

In 2013 the antennas participated in 110 IVS sessions

for a total of 262 antenna days of observing, 116 more

than in 2012. An increase in operations funding in 2013

has enabled us to increase our observing load, including 60 days per year for AUSTRAL which is focused

on high priority geodetic and astrometric programs in

the southern hemisphere. In this report we also briefly

highlight our research activities during 2013 and our

plans for 2014.

1 General Information

As part of AuScope (www.auscope.org.au), the University of Tasmania (UTAS) operates the AuScope VLBI

Array (Lovell et al., 2013), three 12-m diameter radio telescopes on the Australian continent, located near

Hobart (Tasmania), Yarragadee (Western Australia),

and Katherine (Northern Territory).

The Hobart telescope (Hb) is co-located with the

existing 26-m telescope (Ho) to preserve the more than

20-year VLBI time series at the site. Midway between

the 26-m and 12-m telescopes is the HOB2 GNSS installation which has been a core site of the International

GNSS Service (IGS) since its conception. A hut capable of housing a mobile gravimeter is also co-located

1. School of Mathematics and Physics, University of Tasmania

2. School of Geography and Environmental Studies, University

of Tasmania

Hobart 12-m and 26-m, Katherine, and Yarragadee

IVS 2013 Annual Report

on the site. The Yarragadee telescope (Yg) provides a

far western point on the continent and is co-located

with multiple existing geodetic techniques including

SLR, GNSS, DORIS, and gravity. The Katherine site

(Ke) is new and provides a central longitude, northern site. The telescope at Katherine is co-located with a

new GNSS site that forms part of the AuScope GNSS

network.

Each AuScope VLBI observatory is equipped with

a 12.1-m diameter main reflector. The telescope specifications include: 0.3 mm of surface precision (RMS),

fast slewing rates (5 deg/s in azimuth and 1.25 deg/s

in elevation), and acceleration (1.3 deg/s/s). All three

sites are equipped with dual polarization S- and X-band

feeds with room temperature receivers covering 2.2 to

2.4 GHz at S-band and 8.1 to 9.1 GHz at X-band. System Equivalent Flux Densities (SEFDs) are 3500 Jy in

both bands. Data digitization and formatting is managed by the Digital Base Band Converter (DBBC) system, and data are recorded using the Mark 5B+ system.

Each site is equipped with a Hydrogen maser time and

frequency standard.

All three observatories were designed and constructed to be remotely controlled and monitored to

keep operating costs at a minimum. Operation of

the AuScope VLBI array is being carried out from a

dedicated operations room on the Sandy Bay campus

of the University of Tasmania.

2 Staff

Staff at UTAS consists of academics Prof. John Dickey

(director), Dr. Simon Ellingsen, Dr. Christopher Watson, and Prof. Peter McCulloch. Dr. Jim Lovell is

115
116 Lovell et al.

Project Manager for the AuScope VLBI project. Dr.

Jamie McCallum, Dr. Stas Shabala, Dr. Lucia Plank,

and Dr. Anthony Memin are post-doctoral fellows who

are carrying out research aimed at improving geodetic

solutions in the southern hemisphere. Mr. Brett Reid

is the Observatory Manager whose position is funded

by the university. In addition we have an electronics

technical officer, Mr. Eric Baynes. For operation of

the observatories during geodetic observations we rely

heavily on support from astronomy PhD and post graduate students. Logistical and maintenance support at

Katherine is provided by Mr. Martin Ephgrave and at

Yarragadee by Mr. Randall Carman and team at the

MOBLAS5 SLR station.

3 AuScope VLBI Project Status

The AuScope VLBI array is currently funded for operations at the level of up to 170 observing days per

year until mid 2015. This includes 60 days per year

for the AUSTRAL program and, in 2014, the CONT14

campaign. The Hobart 26-m antenna will continue to

participate in IVS observations at the level of twelve

days per year, primarily to assist in the maintenance

and enhancement of the Celestial Reference Frame in

the southern hemisphere. The 26 m will also participate

in CONT14.

4 Geodetic VLBI Observations

In 2013 the AuScope and Hobart 26-m antennas participated in 110 IVS sessions (up from 72 in 2012) for a

total of 262 antenna days of observing, 116 more than

the previous year. A summary of the observations is

presented in Table 1.

4.1 The AUSTRAL Program

The 60 day per year AUSTRAL Program commenced

in July 2013 and will run for two years initially. Observations are being made with the three AuScope antennas as well as the Warkworth 12 m and Hartebeesthoek

15 m (Figure 1). The Hobart 26 m and Hartebeesthoek

Table 1 AuScope and Hobart 26-m antenna participation (number of days) in IVS sessions in 2013. The AUST13 series of observations was a 15-day CONT-like session as part of the AUSTRAL program.

Session Antenna

Ho Hb Ke Yg

APSG 2

AUST13 15 15 15

AUSTRAL 9 9 9

CRDS 6 5 5 3

CRF 1 3 3 4

OHIG 3 3 3

R&D 6 1 1 1

R1 28 26 22

R4 27 22 23

T2 2 2 1

Total 13 95 86 81

26 m also participate for some observations. Scheduling is carried out in VieVS, and data are correlated at

the Curtin University software correlator.

The AUSTRAL observing program is divided into

three streams focused on high priority geodetic and astrometric aims in the southern hemisphere:

1. astrometric observations to monitor and enhance

the southern hemisphere reference frame in preparation for ICRF3;

2. regular observations to improve the density of the

geodetic time series for the southern antennas and

measure and monitor the motion and deformation

of the Australian plate;

3. four 15-day CONT-like sessions over two years to

demonstrate the full capabilities of the array, characterize the level of systematic errors caused by the

troposphere and source structure, and develop and

try error mitigation strategies.

For four experiments during 2014, the 26-m antennas at Hartebeesthoek and Hobart will join the AUSTRAL array. With the same atmosphere and clocks at

each site, and with baselines to each pair observing

the same source structure, we hope to further understand the systematic uncertainties due to troposphere

and source structure.

4.1.1 Post-correlation Data Processing

Starting in late 2012, the University of Tasmania

has begun handling the post-correlation processing

IVS 2013 Annual Report
AuScope VLBI 117

Hartebeesthoek

Katherine

Yarragadee

Hobart

Warkworth

Fig. 1 The AUSTRAL array comprising the AuScope VLBI array, Hartebeesthoek and Warkworth.

of the AUSTRAL experiments correlated at Curtin

University. After the Mark IV data are made available

from Curtin, they are processed using fourfit, and a

correlation report is drafted. We would like to thank

Alessandra Bertarini from Bonn for her extensive

assistance with these procedures. The database creation is currently handled by David Gordon at NASA

GSFC, as the University of Tasmania does not have

CALC/SOLVE currently installed. When the standalone version of dbedit is available, this will be used

to generate and submit the NGS databases directly.

AUSTRAL experiments AUST10 — AUST15 and the

first two sessions of the AUST13 campaign have been

processed and submitted as NGS databases to date.

5 Research Activities

5.1 Source Structure

A key area of research over the past year has involved

investigating the effects of quasar structure and evolution on geodetic solutions. In particular, we have

investigated a number of astrophysical metrics relating to quasars, to see whether these are good predictors of position stability. In Schaap et al. (2013)

we found that scintillating sources (sources that twinkle, showing flux density variability of a few percent

on timescales of days) are significantly more stable

than non-scintillating sources. We have also considered multi-frequency variability of radio sources on

longer timescales in Shabala et al. (2014) and found

that sources which show small time lags between S

and X-band light curves have more stable positions.

We plan to develop this work further in the coming

year, with the ultimate goal of helping schedulers decide which quasars should be included in a given IVS

session.

With TU Wien colleagues Lucia Plank and Johannes Bohm, we have also developed a source  ̈

structure simulator to assess the impact of structure

in geodetic VLBI observations. This simulator is

implemented in the VieVS software, and it allows for

studies of different analysis and scheduling strategies.

In the coming year, we plan to use the simulator to

investigate various analysis and scheduling-based

source structure mitigation techniques, including

“clever” scheduling that takes into account some a

priori knowledge of source structure.

IVS 2013 Annual Report
118 Lovell et al.

5.2 Antenna Structural Deformation Study

Preliminary terrestrial surveys of the Hobart 12-m telescope were undertaken in 2013 in order to:

1. assess our ability to resolve time dependent refraction coefficients throughout a longer automated survey and

2. test the limits of Automated Target Recognition

(ATR) on the Australian Geophysical Observing

System (AGOS) robotic telescope monitoring infrastructure (Leica TDRA6000).

Progress was slower than hoped; however the survey

has now been integrated with local site tie surveys undertaken by Geoscience Australia, with the Hobart survey underway at the time of writing. We aim to compare time dependent IVP determinations using both the

traditional circle fit and the transformation approach,

with results to be submitted in 2014. This submission

will include an analysis of a telescope-wide deployment of thermistors used to characterize the spatial

variability of temperature throughout the small 12-m

steel and aluminium structure. Further work is required

to complete the Finite-Element Analysis of the structure.

References

1. Lovell, J. E. J. et al., 2013, J. Geod 87, 527.

2. Schaap et al. 2013, MNRAS, 434, 585.

3. Shabala et al. 2014, J. Geod. in press, arXiv:1306.0696.

IVS 2013 Annual Report
Kashima 34-m VLBI Station

M. Sekido, E. Kawai

Abstract The Kashima 34-m radio telescope has recovered from the damages to the azimuth wheel and

rail caused by the ‘Tohoku Earthquake’ in March 2011.

VLBI observations, including IVS sessions and single

dish observations, have restarted from April 2013. A

newly developed wideband feed was mounted on the

antenna. The frequency range of 6.4-14 GHz observations in single linear polarization became available.

Further development of the improved feed for the 2-18

GHz frequency range is under progress and expected

to be ready in 2014.

1 General Information

Fig. 1 The Kashima 34-m Radio Telescope in November 2013.

NICT Space-Time Standards Laboratory/Kashima Space Technology Center

NICT Kashima Network Station

IVS 2013 Annual Report

The main facility of the Kashima VLBI station is

the 34-m diameter antenna of modified Cassegrain focus type. This antenna is maintained and operated by

the VLBI group of Space Time Standard Laboratory

in the National Institute of Information and Communications Technology (NICT). The station is also a part

of the Kashima Space Technology Center (KSTC) as a

local branch of the NICT.

Kashima city is located on the east coast of the

main island of Japan. The “Tohoku earthquake” that

occurred in March 2011 affected Kashima city and the

KSTC by destruction of some buildings and a tsunami.

An azimuth wheel and rails of the 34-m antenna were

damaged by the earthquake. The replacement work of

the four azimuth wheels and all the azimuth rail wearstrip plates was done by the end of March 2013. Figure

2 shows the new wheel installed in March 2013. Alignment of each wheel was adjusted by using a telescope

attached at the wheel axis, so that the wheel axis is exactly aligned to the central axis of azimuth circle with

accuracy of 1.e-5 radians. It is important so that the

Fig. 2 Installation work of new azimuth wheel.

119
120 Sekido and Kawai

wheel rolls on the azimuth rail circle without stress.

The flatness of the rail height was required to be within

0.1 mm RMS over the 10-m radius azimuth circle,

which comes from the requirement of antenna tracking accuracy within a tenth beam width for the 43 GHz

receiver. The repair work was completed by the end

of March 2013, and work began with the same performance as before the earthquake.

2 Component Description

2.1 Receivers

The Kashima 34-m antenna is equipped with multiple

receivers from its lowest frequency in L-band up to Qband. The performance parameters for each frequency

are listed in Table 1. Multiple receivers are changed by

exchanging receiver systems at the focal point of the

antenna. Each receiver is mounted on one of the four

trolleys and only one trolley can be at the focal position. The focal position can also be moved by changing

the position and direction of sub-reflector via five axes

of actuators. Thus optimum sub-reflector positions are

adjusted for each receiver. When a feed system is newly

mounted the sub-reflector position is adjusted for that.

L-band:

Radio Frequency Interference (RFI) from the cell

phone base station (1,480 MHz) has become too

strong even to saturate the low noise amplifier (LNA)

of the first stage in the L-band receiver. We installed

a superconductor filter in front of the LNA, whose

pass-band is 1405-1440 MHz and 1600-1720 MHz.

Installation of the filter was completed in December

2013, and we confirmed that the problem of LNA

saturation has been solved.

S-band:

A high temperature superconductor filter has been used

in the S-band receiver since 2002 to avoid RFI of cell

phone IMT-2000. It was located after the LNA instead

of before it because the RFI was not severe enough to

saturate the LNA. On 12 November 2013, the superFig. 3 Superconductor Filter installed inside L-band receiver dewar.

conductor filter lost its function because of the increase

of the filter temperature caused by aging of the cryogenic system. We replaced the filter with a standard

bandpass filter in December. Consequently, its observation frequency range was slightly changed to 2,210-

2,350 MHz.

Wideband:

As one of the important components of the Gala-V

project, which is aimed to make precise frequency

comparisons over a long baseline, a new feed system

(code name: IGUANA) with wideband observation capability was developed and mounted in place of the Cband receiver trolley of the 34-m antenna. Room temperature wideband LNA is used for one linear polarization in that receiver. The current performance of this

antenna is 20-40% efficiency for the 6.4-14 GHz frequency range [1]. A more improved feed is planned to

be installed in 2014.

32 GHz and 43 GHz Receivers:

Startup work on these two receivers is currently not

completed. Therefore, system performance parameters

are not measured in this report.

IVS 2013 Annual Report
Kashima 34-m Station 121

Table 1 Antenna Performance parameters of the Kashima 34-m telescope.

Receiver Pol. Frequency Parameter (2013)

L-band RHCP/LHCP 1405-1440MHz, 1600-1720MHz SEFD ∼ 500Jy

S-band RHCP/LHCP 2210-2350MHz SEFD ∼ 250Jy

X-band RHCP/LHCP 8180-9080MHz SEFD ∼ 370Jy

WIDE V-Linear Pol. 6.4-15GHz SEFD ∼ 1500 Jy

K-band LHCP 22 - 24 GHz SEFD ∼ 1300 Jy

Ka-band RHCP 31.7-33.7GHz NA

Q-band 42.3-44.9GHz NA

Fig. 4 Wideband (IGUANA) feed installed in the receiver room

of Kashima 34m telescope.

2.2 Data Acquisition System

Several VLBI data acquisition systems have been developed and installed in the Kashima 34-m telescope.

K5/VSSP32 [2]: has been employed for all geodetic

VLBI observations as a multi-channel data acquisition system.

K5/VSI data recording systems: is composed of a

PC-VSI data capture card (PCI-X interface) and a

PC with raid disk systems. This system has been

used in combination with an ADS3000+ sampler

for wideband observations (1024Msps/1ch/1bit,

128Msps/1ch/8bit).

K6/OCTAD-G (code name ‘GALAS’) sampler: is

the newly developed sampler for the Gala-V project

[3]. The GALAS samples the RF signal without

frequency conversion and acquires four wideband

signals with 1024 MHz bandwidth via the digital

filter function implemented in it. This sampler

is under evaluation and will be employed for the

project in 2014.

K4/VSOP terminal: has been used for joint astronomical observations with JVN [4].

Network Connections and Data Server

Due to the collaboration with JGN-X, a high speed research network provider hosted by NICT, the 10 Gbps

network is available between the Kashima and Koganei

stations. Due to the limiting of network switch and connection, the VLBI data server used for e-VLBI data

transfer is connected via 1 Gbps network to the Internet. Therefore about 600 Mbps in/out transfer speed

is constantly available. Currently three data servers are

operated for e-VLBI data exchanges (Table 2).

Table 2 Data servers at Kashima Station and its capacity.

Hostname Path Disk Size

vlbi2.jp.apan.net /vlbi2/ 12 T Bytes

k51b.jp.apan.net /vlbi3/ 26 T Bytes

k51c.jp.apan.net /vlbi4/ 24 T Bytes

3 Staff

Kawai Eiji: is the main engineering researcher

in charge of the hardware maintenance and the

operation of the Kashima 11-m and 34-m antennas

[5]. He is responsible for routine geodetic VLBI

observations for IVS.

Hasegawa Shingo: is supporting staff for IVS observation preparation and maintenance of file servers

for e-VLBI data transfer.

IVS 2013 Annual Report
122 Sekido and Kawai

Tsutsumi Masanori: is supporting staff for data acquisition PCs and networks.

Takefuji Kazuhiro: is a researcher using the 34-m

antenna for the Gala-V project and the Pulsar observations. He performed startup work of the wideband

IGUANA receiver including adjusting sub-reflector

position and measured the SEFD of the new receiver.

Ujihara Hideki: has designed the new wideband

IGUANA feed.

Ichikawa Ryuichi: is in charge of keeping GNSS stations and GNSS observations.

Sekido Mamoru: is responsible for the Kashima 34-

m antenna as the group leader. He is maintaining

Field System FS9 software for this station and operating the Kashima and Koganei 11-m antennas [5]

for IVS sessions.

4 Current Status and Activities

The Kashima 34-m telescope has completely recovered from the damage of the “Tohoku earthquake” and

has rejoined VLBI observations (IVS-T2, IVS-CRF,

JADE, and JVN) and single dish observations (SgrA* and Jupiter) since April 2013. Strong RFIs in Lband became more severe from cell phone base stations. We observed saturation of LNA in the worst case

scenario and decided to introduce a superconductor filter in front of the LNA as a countermeasure. Production

and installation of the filter was completed in December 2013. Now we confirmed that the filter suppresses

RFI signal from cell phone base stations and receiver

performance was recovered.

The main mission of the VLBI group of NICT

is the development of VLBI systems for distant frequency comparison. That project, named GALA-V [3],

includes upgrading the receiver of the 34-m telescope

to enable wideband observation in frequency range 2.2

- 18 GHz, which covers the frequency range (2-14

GHz) of VGOS [6]. Based on the requirement of narrow beam width on the wideband feed, original designing of the feed system was made for the 34-m telescope.

5 Future Plans

Evaluation of the wideband receiver system will be performed in 2014. Additionally, an improved version of

the feed is under development and expected to be ready

in the first half of 2014. Wideband VLBI observations

in combination with small diameter antennas and the

Kashima 34-m telescope will be performed, and engineering evaluation including feed, sampler, and phase

calibration systems will be made.

Acknowledgements

The development of the wideband feed was supported

by the “Joint Development Research” fund provided

from the National Astronomical Observatory of Japan

in 2013. We acknowledge Professor K. Fujisawa of Yamaguchi University and M. Honma and M. Matsumoto

of NAOJ for supporting this development. We thank

the research network JGN-X and the Information System Section of NICT for supporting the network environment for e-VLBI.

References

1. Takefuji, K., H. Ujihara, “NICT Technology Development

Center 2013 Annual Report”, International VLBI Service

for Geodesy and Astrometry 2013 Annual Report, edited by

K. D. Baver, D. Behrend, and K. L. Armstrong, this volume,

2014.

2. Kondo,T., Y. Koyama, R.Ichikawa, M.Sekido, E.Kawai, and

M.Kimura, Development of the K5/VSSP System, J. Geod,

Soc. Japan, Vol. 54, No 4, pp. 233-248, 2008.

3. Sekido M., et al., Development of Wide-band VLBI system

(Gala-V), IVS NICT-TDC News No 33, pp.11-14, 2013.

4. Doi, A., Japanese VLBI Network, Proceedings of the 8th

European VLBI Network Symposium. September 26-29,

2006,Torun, Poland., pp.71-74, 2006.

5. Sekido, M., E. Kawai, “Kashima and Koganei 11-m VLBI

Stations”, International VLBI Service for Geodesy and Astrometry 2013 Annual Report, edited by K. D. Baver, D.

Behrend, and K. L. Armstrong, this volume, 2014.

6. Petrachenko, B.: VLBI2010: Progress and Challenges, IVS

2012 General Meeting Proceedings, edited by D. Behrend

and K. D. Baver, NASA/CP-2012-217504, p.42-46, 2012.

IVS 2013 Annual Report
Kokee Park Geophysical Observatory

Ron Curtis

Abstract This report summarizes the technical parameters of the VLBI system at the Kokee Park Geophysical Observatory and provides an overview of the activities that occurred in 2013.

1 Location

The Kokee Park Geophysical Observatory (KPGO) is

located at Kokee State Park on the island of Kauai

in Hawaii at an elevation of 1,100 meters near the

Waimea Canyon, often referred to as the Grand Canyon

of the Pacific. KPGO is located on the map at longitude

159.665◦ W and latitude 22.126◦ N.

2 Technical Parameters

The receiver is of NRAO (Green Bank) design (dual

polarization feed using cooled 15 K HEMT amplifiers). The antenna is of the same design and manufacture as those used at Green Bank and Ny-Alesund. A  ̊

Mark 5B+ recorder is currently used for all data recording.

Timing and frequency is provided by a Sigma Tau

Maser with a NASA NR Maser providing backup.

Monitoring of the station frequency standard performance is provided by a CNS (GPS) Receiver/Computer

1. USNO

2. NASA GSFC

Kokee Park Network Station

IVS 2013 Annual Report

system. The Sigma Tau performance is also monitored

via the IGS Network.

3 Staff

The staff at Kokee Park consists of six full time people

employed by ITT Exelis under the SCNS contract to

NASA for the operation and maintenance of the observatory. Chris Coughlin, Lawrence Chang, Kiah Imai,

and Ron Curtis conduct VLBI operations and maintenance. Ben Domingo is responsible for antenna maintenance, with Amorita Apilado providing administrative, logistical, and numerous other support functions.

Kelly Kim also supports VLBI operations and maintenance during 24-hour experiments and as backup support.

4 Mission Support

Kokee Park has participated in many VLBI sessions including IVS R4 and R1. KPGO also participates in the

RDV, CRF, and OHIG sessions. KPGO averaged two

experiments of 24-hour duration each week, with daily

Intensive experiments, in 2013. KPGO began supporting the Saturday INT2 weekend Intensive experiments

in May 2013 while the Tsukuba VLBI station was performing repairs. The KPGO support of the weekend

Intensive experiments concludes in January 2014.

Kokee Park hosts other systems — a Doppler

Orbitography and Radiopositioning Integrated by

Satellite (DORIS) beacon and remote control, a

Quasi-Zenith Satellite System (QZSS) monitoring

123
124 Curtis

station, a Two-Way Satellite Time and Frequency

Transfer (TWSTFT) relay station, and a Turbo-Rogue

GPS receiver. Kokee Park is an IGS station.

5 Recent Activities

The KPGO 20-m antenna has been in service for

21 years and continues to show signs of its age. In

April 2013, the KPGO 20-m antenna construction

contractor, GD Satcom, made a site visit to KPGO to

implement some changes to the KPGO 20-m antenna

configuration in an effort to reduce the wear on the

azimuth bull gear teeth due to the axial play in the

azimuth bearing. Those changes included re-alignment

of the azimuth drives to improve teeth mesh between

the azimuth pinions and the bull gear. They also tuned

the servo system to decrease the acceleration and

deceleration of both the azimuth and elevation drive

systems. Plans are moving forward to upgrade the

KPGO 20-m telescope for broadband observation.

KPGO received a new broadband receiver box from

MIT under contract from USNO in October 2013. The

digital backend is in the process of being configured

with four each RDBE’s, UP/DOWN converters,

and Mark 5C recorders in addition to an Optical

Receiver/Splitter/Amplifier (ORCA). Only one of

the four Mark 5C recorders has been received so far.

InterTronic Solutions was awarded a contract to build

and install a 12-m high precision VLBI2010-style

radio antenna at KPGO in support of USNO. The

broadband feed to be used on this 12-m telescope

will be of MIT design. Installation is projected for

completion in 2015.

The e-transfer of the INT1 sessions from KPGO to

USNO continues to be transmitted over the microwave

infrastructure provided by the Pacific Missile Range

Facility (PMRF) and connects KPGO to DREN. Plans

to migrate to a dedicated fiber connection to DREN at

PMRF have been delayed due to damage to the fibers

by a wildfire. MIT is working with the Hawaii Intranet

Consortium (HIC) and DREN to improve the KPGO

e-transfer rate. Long term plans are still to make realtime VLBI data transfers from KPGO a reality.

6 Outlook

KPGO will continue with efforts to upgrade the 20-

m antenna signal path to VLBI2010 specifications.

KPGO staff, ITT Exelis personnel at GSFC, USNO

personnel, and MIT personnel are in the process of

planning the 20-m antenna modifications and the installation of a new broadband front end for the KPGO

20-m antenna.

PMRF is working on acquiring funding for repairs

to the fiber runs that were damaged by a wild fire in

2012. Those repairs, as well as the dedicated fiber path

to HIC/DREN for KPGO e-transfers, are on hold until

funding is acquired. USNO, NASA, InterTronic Solutions, MIT, and Exelis will continue working throughout 2014 on the construction process for the high precision VLBI2010-style radio telescope at KPGO.

Fig. 1 20-m digital backend.

IVS 2013 Annual Report
Kokee Park 2013 Report 125

Fig. 2 20-m broadband feed.

Table 1 Technical parameters of the radio telescope at KPGO.

Parameter Kokee Park

owner and operating agency USNO-NASA

year of construction 1993

radio telescope system Az-El

receiving feed primary focus

diameter of main reflector d 20m

focal length f 8.58m

f /d 0.43

surface contour of reflector 0.020inchesrms

azimuth range 0...540◦

azimuth velocity 2

◦/s

azimuth acceleration 1

◦/s2

elevation range 0...90◦

elevation velocity 2

◦/s

elevation acceleration 1

◦/s2

X-band

(reference ν = 8.4GHz,λ = 0.0357m)

8.1−8.9GHz

Tsys 40K

SSEFD(CASA) 900Jy

G/T 45.05dB/K

η 0.406

S-band

(reference ν = 2.3GHz,λ = 0.1304m)

2.2−2.4GHz

Tsys 40K

SSEFD(CASA) 665Jy

G/T 35.15dB/K

η 0.539

VLBI terminal type VLBA/VLBA4-Mark 5

Field System version 9.11.1

IVS 2013 Annual Report
Kashima and Koganei 11-m VLBI Stations

M. Sekido, E. Kawai

Abstract The Kashima and Koganei 11-m stations

have been used for geodetic and astronomical monitoring observations and as an R&D test bed of VLBI

technology. Unfortunately the Kashima 11-m station

has stopped due to an accidental cable break that happened in October 2013. This will be fixed in early

March 2014. The Koganei 11-m antenna has been constantly operated for VLBI and satellite down-link observations.

1 General Information

A pair of 11-m diameter antennas is operated by

the VLBI group of Space-Time Standard Laboratory

(STSL) of the National Institute of Information and

Communications Technology (NICT). The Kashima

11-m antenna is located in Kashima Space Technology

Center (KSTC), on the east coast of the Japanese

main island. The Koganei 11-m antenna is located in

the headquarters of the NICT in Tokyo (Figure 1).

The 11-m VLBI antennas at Kashima and Koganei

(Figure 2) were established and have been operated

for the monitoring of crustal deformation of the Tokyo

metropolitan area (Key Stone Project) since 1995

[1]. After regular VLBI observations, the KSP VLBI

Network terminated in 2001. Since then, the 11-m

VLBI stations at Kashima and Koganei have mainly

been used for research and technology developments.

“The Tohoku earthquake” that occurred in March 2011

NICT Space-Time Standards Laboratory/Kashima Space Technology Center

NICT KSP Network Station

IVS 2013 Annual Report

Fig. 1 Location of NICT-Koganei Headquarters, and Kashima.

affected Kashima city and the KSTC by the destruction

of some buildings and by a tsunami. Fortunately the

damage to the Kashima 11-m antenna was not as

severe as that of the Kashima 34-m antenna. The

Koganei 11-m antenna in Tokyo was also safe. Thus

two antennas could be used for measurements of postseismic crustal deformation of the Kashima-Koganei

baseline. The Kashima and Koganei 11-m stations

participated in IVS-R1, T2, and APSG sessions from

May 2011 and August 2011, respectively.

126
Kashima and Koganei VLBI Stations 127

Fig. 2 11-m VLBI antennas at Kashima (left panel) and Koganei (right panel).

Table 1 The antenna parameters of the 11-m antennas.

Kashima Koganei

Antenna Type Cassegrain type

Diameter 11-m

Mount Style Az El mount

Latitude N 35◦ 57’ 19.46” N 35◦ 42’ 37”.89

Longitude E 140◦ 39’ 26.86” E 139◦ 29’ 17”.06

Altitude 62.4 m 125.4 m

S band 2212 ∼ 2360 2212 ∼ 2360

Rx Freq. X Low band 7700 ∼ 8200 7700 ∼ 8200

[ MHz ] X High band 8180 ∼ 8680 8100 ∼ 8600

S band 3000 3000

Local Freq. X Low band 7200 7200

[ MHz ] X High band 7680 7600

SEFD [ Jy ] X-band 5700 9500

S-band 3300 5500

2 Component Description

2.1 Antenna

The antenna parameters of Kashima-11 and Koganei11 are summarized in Table 1. The band-pass filters for

S-band (2212-2360 MHz) were installed in 2010 for radio frequency interference mitigation at both stations.

2.2 Data Acquisition System: Sampler

Two sorts of sampler are available at both stations as

summarized in Table 2. The K5/VSSP32 [2] has four

channels of video band signal input per unit. Four units

of K5/VSSP32 constitute one geodetic VLBI terminal with 16 inputs. This system is constantly used for

geodetic VLBI observations. This sampler has digital

filter functionality realized by FPGA in it. The input

video signal is digitized with 8-bit quantization with

64 MHz sampling. Then the frequency bandwidth is

restricted and output by reduced data rate for requested

sampling mode. The output data is written to a standard

Linux file system in K5/VSSP32 format. Data format

conversion from K5/VSSP32 to Mark IV, VLBA, and

Mark 5B are possible with conversion tools1.

The ADS3000+ [3] is a sampler with digital baseband conversion (DBBC) function. Several kinds of

data acquisition modes (personalities) are switchable

by loading FPGA program. The DBBC mode enables

flexible selection of 16 video frequency channels with

any of 4/8/16/32 MHz bandwidth. Therefore this can

be compatible with conventional 16 channels of geodetic VLBI observations. One channel of 8 bits with 128

MHz sampling mode has been used for astronomical

observations with a higher dynamic range, such as pulsar observations. Another channel of 1/2-bit 1024 MHz

1 Observation and data conversion software for K5/VSSP are

freely available from http://www2.nict.go.jp/aeri/

sts/stmg/K5/VSSP/index-e.html

IVS 2013 Annual Report
128 Sekido and Kawai

Table 2 VLBI data sampler/DAS system available at the

Kashima and Koganei 11-m stations.

System K5/VSSP32(4 units) ADS3000+(K5/VSI)

Video Converter K4/KSP 16ch not necessary

# of Input Channels 4 /unit x 4 units 1 or 2

# of Output Channels 16 1,2, 16

Input Freq. Range 0 - 300 MHz 0 - 2 GHz

Sampling Rate 0.04,0.1,0.2,0.5,1, 128, 256, 1024,

[Msps] 2,4,8,16,32,64 2048,4096

Quantization bit 1,2,4,8 bit

Max. data rate [Mbps] 256 /unit x 4 4096

Output Interface USB 2.0 VSI-H

sampling is used for wide-band single channel VLBI

observations. This mode is going to be used in the

Gala-V project [4].

2.3 Network Connection

The local area network connections from the Kashima

34-m antenna site to the Kashima 11 m and the Koganei 11 m are 10 Gbps and 1 Gbps, respectively. The

observational data of IVS sessions are gathered to the

e-VLBI data server at the Kashima 34-m site, and then

those data are provided to the correlator through a 1

Gbps network link of the Japanese research network

JGN-X.

3 Staff

Kawai Eiji: In charge of station care/maintenance

and IVS observations.

Hasegawa Shingo: Supporting staff for IVS observation preparation, operation, and maintenance of file

servers for e-VLBI data transfer.

Ichikawa Ryuichi: In charge of GNSS station care

and GNSS observations.

Sekido Mamoru: In charge of overall activities of the

Kashima and Koganei VLBI stations.

4 Current Status and Activities

The Kashima and the Koganei 11-m stations are participating in geodetic VLBI sessions IVS-T2, APSG,

and JADE, about once a month. These two stations are

used as a test bed of R&D experiments including a feasibility study of frequency comparison with VLBI. In

addition, flux monitoring of Sgr-A* with the Kashima

— Koganei baseline has been performed in collaboration with S. Takekawa and T. Oka of Keio University

[5].

However a tear of cables (coaxial cables and statuscontrol lines) happened at the Kashima 11-m antenna

in October 2013 by accident. It was caused by aging

and the breaking of strings for cable binding. Loosened cables were caught on the antenna structure during observing. Then they were stretched and torn by

antenna motion. The work of replacing the cables was

contracted and expected to be finished by early March

2014.

The Koganei 11-m antenna is jointly operated by

two groups in the NICT; the STSL and the Space

Weather and Environment Informatics Laboratory

(SWEIL). When the antenna is not used for VLBI

observations, it is used for down link observations

from the Stereo satellite 2 by the SWEIL.

5 Future Plans

As medium size radio telescopes, the Kashima and the

Koganei 11-m antennas have good slew speed (3 degrees/sec) and stable observation performance. This interferometer will be continuously used for good R&D

VLBI experiments.

Acknowledgements

We thank the research network JGN-X and the Information System Section of NICT for supporting the network environment for e-VLBI.

2 http://www.nasa.gov/mission pages/stereo/main/index.html

IVS 2013 Annual Report
Kashima and Koganei VLBI Stations 129

References

1. Special issue for the Key Stone Project, J. Commun. Res.

Lab., Vol. 46, No. 1, pp.1-221, 1999.

2. Kondo,T., Y. Koyama, R. Ichikawa, M. Sekido, E. Kawai,

and M. Kimura, Development of the K5/VSSP System, J.

Geod, Soc. Japan, Vol. 54, No 4, pp. 233-248, 2008.

3. Takefuji, et al., “Next-generation A/D Sampler ADS3000+

for VLBI2010”, in VLBI2010: From Vision to Reality, Proceedings from the Sixth IVS General Meeting. Held 7-13

February, 2010 in Hobart, Tasmania, Australia. Edited by D.

Behrend and K.D. Baver. NASA/CP 2010-215864., p.378-

382, 2010.

4. Sekido M., et al., Development of Wide-band VLBI system

(Gala-V), IVS NICT-TDC News No.33, pp.11-14, 2013.

5. Takekawa, S.; Oka, T.; Sekido, M., “Progress Report of the

NICT VLBI Monitoring Observations of Sgr A* at 2 GHz

and 8 GHz”, The Astronomer’s Telegram, #5467, 2013.

IVS 2013 Annual Report
Matera CGS VLBI Station 2013 Annual Report

Giuseppe Bianco 1, Giuseppe Colucci 2, Francesco Schiavone 2

Abstract This report presents the status of the Matera

VLBI station. An overview of the station, some technical characteristics of the system, and staff addresses

are also given.

1 General Information

The Matera VLBI station is located at the Italian Space

Agency’s ‘Centro di Geodesia Spaziale G. Colombo’

(CGS) near Matera, a small town in the south of Italy.

The CGS came into operation in 1983 when the Satellite Laser Ranging SAO-1 System was installed. Fully

integrated into the worldwide network, SAO-1 was

in continuous operation from 1983 up to 2000, providing high precision ranging observations of several

satellites. The new Matera Laser Ranging Observatory

(MLRO), one of the most advanced Satellite and Lunar

Laser Ranging facilities in the world, was installed in

2002, replacing the old SLR system. CGS also hosted

mobile SLR systems MTLRS (Holland/Germany) and

TLRS-1 (NASA).

In May 1990, the CGS extended its capabilities to

Very Long Baseline Interferometry (VLBI), installing a

20-m radio telescope. Since then, Matera has observed

in 876 sessions up through December 2012.

In 1991 we started GPS activities, participating

in the GIG 91 experiment and installing at Matera

a permanent GPS Rogue receiver. In 1994, six TurboRogue SNR 8100 receivers were purchased in

1. Agenzia Spaziale Italiana 1

2. e-geos - an ASI/Telespazio company

Matera Network Station

IVS 2013 Annual Report

order to create the Italian Space Agency GPS fiducial

network (IGFN). At the moment 12 stations are

part of the IGFN, and all data from these stations,

together with 24 other stations in Italy, are archived

and made available by the CGS Web server GeoDAF

(http://geodaf.mt.asi.it).

In 2000, we started activities with an Absolute

Gravimeter (FG5 Micro-G Solutions). The gravimeter

operates routinely at CGS and is available for external

campaigns on request.

Thanks to the co-location of all precise positioning space based techniques (VLBI, SLR, LLR, and

GPS) and the Absolute Gravimeter, CGS is one of the

few “fundamental” stations in the world. With the objective of exploiting the maximum integration in the

field of Earth observations, in the late 1980s, ASI extended CGS’ involvement to include remote sensing

activities for present and future missions (ERS-1, ERS2, X-SAR/SIR-C, SRTM, ENVISAT, and COSMOSkyMed).

The Matera VLBI antenna is a 20-meter dish with

a Cassegrain configuration and an AZ-EL mount. The

AZ axis has ±270 degrees of available motion. The

slewing velocity is 2 deg/sec for both the AZ and the

EL axes.

The technical parameters of the Matera VLBI antenna are summarized in Table 1.

The Matera time and frequency system consists of

three frequency sources (two Cesium beam and one Hmaser standard) and three independent clock chains.

The iMaser 3000 H-maser from Oscilloquartz is used

as a frequency source for VLBI.

130
CGS/Matera 2013 Report 131

Fig. 1 VLBI antenna and MLRO dome.

Table 1 Matera antenna technical specification.

Parameter name Values (S/X)

Input frequencies 2210−2450 MHz / 8180−8980 MHz

Noise temperature <20 K

at dewar flange

IF output frequencies 190−430 MHz

100−900 MHz

IF Output Power

(300 K at inp. flange) 0.0 dBm to +8.0 dBm

Gain compression <1 dB at +8 dBm output level

Image rejection >45 dB within the IF passband

Inter modulation At least 30 dB below each of 2 carriers

products at an IF output level of 0 dBm per carrier

Tsys 55/65 K

SEFD 800/900 Jy

2 Activities during the Past Year

At the end of 2013, the new T4SCIENCE iMaser 3000

was installed. It replaced the >20 years old EFOS-8

maser that was installed at the beginning of the VLBI

activities in Matera.

Specifications for this new maser can be found

here: http://www.t4science.com/product/imaser 3000

IVS 2013 Annual Report
132 Bianco et al.

Fig. 2 Observation time.

3 Current Status

In 2013, 52 sessions were observed. Figure 2 shows a

summary of the total acquisitions per year, starting in

1990.

In 2004, in order to fix the existing rail problems,

a complete rail replacement was planned. In 2005, due

to financial difficulties, it was instead decided that only

the concrete pedestal under the existing rail would be

repaired. From then on, no rail movements have been

noted [1]-[3].

4 Future Plans

In order to plan the eventual building of a VLBI2010

system, the fund raising investigation process has begun. At this moment it is not clear when the budget for

starting the project will be ready.

IVS 2013 Annual Report
Medicina Station Status Report

Andrea Orlati, Alessandro Orfei, Giuseppe Maccaferri

Abstract General information about the Medicina

Radio Astronomy Station, the 32-m antenna status,

and the staff in charge of VLBI observations are

provided. Updates to the hardware were performed

and are briefly described.

1 The Medicina 32-m Antenna: General

Information

The Medicina 32-m antenna is located at the Medicina

Radio Astronomy Station. The station is run by the Istituto di Radioastronomia and is located approximately

33 km east of Bologna. The Consiglio Nazionale delle

Ricerche was the funding agency of the Istituto di

Radioastronomia until the end of 2004. Since January 1, 2005, the funding agency has been the Istituto

Nazionale di Astrofisica (INAF). The antenna, which

was inaugurated in 1983, has regularly taken part in

IVS observations since 1985 and is an element of the

European VLBI network.

A permanent GPS station (MEDI), which is a part

of the IGS network, is installed in the vicinity. Another

GPS system (MSEL) is installed near the VLBI telescope and is part of the EUREF network.

Istituto di Radioastronomia INAF, Medicina

Medicina Network Station

IVS 2013 Annual Report

2 Current Status and Activities

• Antenna - VLBI and e-VLBI experimental tests

were performed by using fiber optic link instead

of coaxial cables to send receiver outputs to VLBI

data acquisition system. Fringes were found and

compared to the fringes obtained by the coaxial

link, nothing of significantly different was observed. Fiber optic link allows much less band

disequalization with respect to coaxial connection

when using large bandwidth receivers, so Medicina

will use fiber optics from now on.

• DBBC - Many VLBI tests were performed in

combination with a Mark 5C in parallel with

the Mark IV. We are currently running version

104 (Aug14) of the firmware. The FILA10G is

now equipped with a new release of the firmware

(provided by HAT LAB), in order to work around

the problem related to the decimation and the track

mapping of the Mark 5C (see below).

• Mark 5C - After the repair and upgrade by Conduant, the unit still showed many problems, even if

the larger part of them has been solved. The crucial

issues still under investigation are:

133
134 Orlati et al.

Fig. 1 View of the Medicina 32-m dish taken during a geodetic VLBI observations.

– decimation and track mapping capabilities are

not yet implemented in Mark 5C software, This

prevents the unit to work fully compliant to

Mark 5B mode.

– reliability and robustness of drs program. We

are currently running a buggy version 0.9.9−1.

The latest release 0.9.9−19 is not usable at all,

the system crashes every time reset=erase

is performed.

• Field System - Release 9.11.4 was installed and almost completed with testing. In order to make our

FS able to command our Mark 5C, we put in place

some ad-hoc solutions. Hopefully we are now able

to run a VLBI observation fully compliant to other

Mark 5B stations.

The new H-Maser was installed and is regularly

used for observation.

The cryogenics of the S/X receivers were restored.

3 Staff

Giuseppe Maccaferri returned to his full-time position

during 2013.

4 Geodetic VLBI Observations

In 2013, Medicina took part in 31 24-hour routine geodetic sessions (namely three IVS-T2, 20

IVS-R4, three EUROPE, two RDV, and three R&D

experiments).

IVS 2013 Annual Report
Metsahovi Radio Observatory Network Station 2013 Annual  ̈

Report

Minttu Uunila 1, Nataliya Zubko 2, Markku Poutanen 2, Juha Kallunki 1, Ulla Kallio 2

Abstract In 2013, Metsahovi Radio Observatory, to-  ̈

gether with Finnish Geodetic Institute, observed seven

IVS sessions, five T2 sessions, and two EUROPE sessions. Old analog BBCs and Mark 5A were retired

during the year, and were replaced by a DBBC and

a Mark 5B+. In September, Metsahovi participated in  ̈

a 4 Gbps e-VLBI demo with a FlexBuff recorder and

vlbi streamer software that were both developed at the

site. Both worked perfectly. A new axis offset for the

antenna was calculated.

1 General Information

Aalto University Metsahovi Radio Observatory and  ̈

Finnish Geodetic Institute (FGI) are two separate institutes which together form the Metsahovi IVS Network  ̈

Station. Metsahovi Radio Observatory operates a 13.7  ̈

meter radio telescope on the premises of Aalto University at Metsahovi, Kylm  ̈ al ̈ a, Finland, about 35 km from  ̈

the university campus. In the same area near Metsahovi  ̈

Radio Observatory, there is the Metsahovi Fundamen-  ̈

tal Geodetic Station of FGI.

2 Component Description

The Metsahovi Radio Observatory has been opera-  ̈

tional since 1974. The telescope was upgraded between

1. Aalto University Metsahovi Radio Observatory  ̈

2. Finnish Geodetic Institute

Metsahovi Network Station  ̈

IVS 2013 Annual Report

1992-1994. The radome was replaced with a new one,

and new surface panels were installed. Metsahovi and  ̈

FGI began observing IVS T2 sessions and EUROPE

sessions in 2004. Approximately six to eight sessions

are observed per year. The surface accuracy of the

present telescope is 0.1 mm (rms). The speed of the

Metsahovi antenna is 1.2 degrees per second.  ̈

Metsahovi is known for its long-term quasar mon-  ̈

itoring. Astronomical VLBI observations are carried

out with the 22 GHz receiver. The geodetic VLBI receiver of Metsahovi uses right circular polarization and  ̈

8.15-8.65 and 2.21- 2.35 GHz frequency bands.

2.1 Metsahovi Fundamental Station  ̈

Finnish Geodetic Institute is running the Metsahovi  ̈

Fundamental Station. It is a part of the IAG GGOS

Core station network. The instrumentation includes

geodetic VLBI (in co-operation with Aalto University), Satellite Laser Ranging (SLR), DORIS,

GNSS, and absolute and superconducting gravimeters.

Currently, instrumentation is being renewed based

on special funding from the Ministry of Agriculture

and Forestry. During the next four years, the plan

includes a new VGOS compatible radio telescope. FGI

is committed to maintain and develop Metsahovi as a  ̈

geodetic fundamental station.

135
136 Uunila et al.

Fig. 1 Metsahovi Radio Observatory (photo by Riku Pihlanto).  ̈

3 Staff

FGI is responsible for the geodetic VLBI observations

and is the owner of the S/X receiver. The radio telescope is owned and operated by the Aalto University,

and an annual agreement is made on its use for geodetic

VLBI sessions. It is not possible to increase the number

of annual sessions (currently six to eight) because the

telescope is mainly used for astronomical observations.

Operation during the geo-VLBI sessions and technical

questions are handled jointly; all other technical work,

telescope maintenance, and maintenance of instrumentation are done by the personnel of the radio telescope.

Metsahovi Radio Observatory personnel working  ̈

with IVS observations are listed in Table 1. From June

2013 D.Sc.(tech.) Minttu Uunila has been in charge

of IVS VLBI observations at Metsahovi replacing, Dr.  ̈

Elizaveta Rastorgueva-Foi. The preparation, operation

of IVS observations, and submission of data are provided by staff from FGI. The personnel engaged in the

work are listed in Table 1.

4 Current Status and Activities

4.1 IVS Sessions

Metsahovi and FGI observed seven IVS sessions, five  ̈

T2 sessions and two EUROPE sessions in 2013. The

first session, T2089, was observed with two recording systems in parallel: the old system with analogue

BBCs and Mark 5A and the new one with DBBC

and Mark 5B. During the T2089, some problems with

the DBBC in channels 05-08 were detected. The data

with an analog system were of better quality and were

used by correlators. All next sessions were recorded

only with the new system (DBBC and Mark 5B). The

problems with the DBBCs channels 05-08 continued

throughout 2013. DBBC boards will be repaired in

2014 (see in BBC/DBBC status). Due to problems with

DBBC and Mark 5 during session T2090, the amount

of correlated data was only 40 %. T2093, EUR126

and T2094 were almost problem free. However, during

some scans, the antenna was slewing.

IVS 2013 Annual Report
Metsahovi 2013 Report  ̈ 137

Table 1 Staff at Metsahovi Radio Observatory and at FGI involved in geodetic observ  ̈ ations during 2013.

Staff at Metsahovi Radio Observatory  ̈

Name Title Responsibility

Dr. Juha Kallunki Laboratory manager VLBI equipment, NEXPReS

M.Sc.(tech.) Ari Mujunen Laboratory manager NEXPReS

Dr. Elizaveta Rastorgueva-Foi VLBI friend VLBI observations

D.Sc.(tech.) Minttu Uunila post-doctoral researcher, IVS on-site technical contact VLBI equipment, IVS observations

M.Sc.(tech.) Petri Kirves Operating engineer Receivers

Tomi Salminen Research assistant (until 6/2013) NEXPReS

Staff at Finnish Geodetic Institute

Name Title Responsibility

Prof. Markku Poutanen Head of the Department of Geodesy and Geodynamics Metsahovi research station  ̈

Dr. Nataliya Zubko Senior research scientist IVS observations, analysis

M.Sc. Veikko Saaranen Special research scientist operation of IVS observations

M.Sc. Ulla Kallio Senior research scientist Local ties measurements

M.Sc. Simo Marila Research scientist operation of IVS observations

Dr. Diego Meschini Research scientist research on correlation

Dr. Jyri Nar ̈ anen  ̈ Special research Scientist Metsahovi infrastructure  ̈

4.2 Technical Activities and Issues

4.2.1 BBC/DBBC status

The old analog rack retaired in early 2013. The

DBBC arrived in September 2012 with the stand-alone

FILA10G. We had some issues with one group-of-four

BBCs (BBC05-08) and the boards will be repaired in

January 2014.

4.2.2 Recording systems

We developed a new DAQ system, the FlexBuff, using

COTS components. Local UDP streaming performance

tests were performed with wirespeed 10GE. Long (30

minute) tests demonstrated the ability to write at maximum wire speed with zero packet loss. Writing 34

disks without a network (using local machines), the architecture can handle 40 Gbps, and it can always handle >30 Gbps. A 4 Gbps e-VLBI demo in September proved that the FlexBuff and its recording software vlbi streamer work impeccably. Also FILA10G

was imployed in the test to enable 4 Gbps recording.

Our old Mark 5A was retired. We had problems

with our Mark 5B+ Stream Stor board, but now at the

end of the year we received it back from warranty repair by Conduant. We have loaned a Mark 5C StreamStor board from the Max Planck Institute for Radio

Astronomy. 2014 will start with testing the repaired

board.

We have switched to using JIVE’s jive5ab instead

of DIMino.

4.3 Data Analysis

In 2010, FGI and Metsahovi Radio Observatory re-  ̈

ceived funding for four years from the Academy of

Finland to start geodetic VLBI data analysis. In 2013,

one doctoral dissertation was finished (M. Uunila: “Improving geodetic VLBI: UT1 accuracy, latency of results and data quality monitoring”).

Data analysis at FGI is performed by N. Zubko. The

project of source structure study and its influence on estimated geodetic VLBI parameters has been continued

in cooperation with E. Rastorgueva-Foi. Diego Meschini is responsible for correlation.

Fig. 2 Metsahovi radio telescope.  ̈

IVS 2013 Annual Report
138 Uunila et al.

4.3.1 Axis offset calculations

The new value of the axis offset -3.6 mm was estimated

from local tie measurements performed by Ulla Kallio

during the geo-VLBI sessions since 2008. The offset

is different from the earlier value +5.1mm estimated

using the time delay observations. We investigated the

effect of changing the offset on the coordinates by analyzing the geodetic VLBI campaigns with the old and

the new axis offset values [1]. The difference between

the old and new coordinates show that the agreement

between the vectors from the IGS GPS point METS

to the reference point of the VLBI telescope Metsahov

calculated from ITRF coordinates and estimated from

local tie data could improve when using the new value.

4.3.2 Local Ties between VLBI and GPS at

Metsahovi  ̈

The local tie measurements between the co-located instruments at Metsahovi are provided by Ulla Kallio.  ̈

A local tie between IGS station METS and the VLBI

antenna reference point was regularly performed with

kinematic GPS measurements during the geo-VLBI

campaigns starting in 2008. Testing shows that a millimeter level accuracy can be achieved in local tie

vector determination with the kinematic GPS method.

In 2013, the influence of thermal deformations in the

local tie vector were studied and taken into account

in data processing. In June 2013, the GPS antennas

were taken down and sent to Gottfried Wilhelm Leibniz Universitaet Hannover and Rheinische FriedrichWilhelms-Universitaet Bonn for calibration as a part of

the EMRP SIB60 (European Metrology Research Programme, Metrology for long distance surveying). The

antennas will be re-established in January 2014.

4.3.3 Meetings

An IVS training school on VLBI for Geodesy and

Astrometry was organized at Aalto University in Espoo, Finland on March 2–5, 2013. The meeting was

sponsored by IVS, the European Geosciences Union

(EGU), Onsala Space Observatory (OSO), RadioNet,

Aalto University and the Finnish Geodetic Institute. A

total of 60 people participated in the School.

Fig. 3 Group photo of EVGA excursion to Metsahovi.  ̈

The school was followed by the 21st Meeting of

the European VLBI Group for Geodesy and Astrometry (EVGA) and the 14th IVS Analysis Workshop on

March 5–8, 2013. The number of participants was 70.

A half-day trip to Metsahovi was made on the last day  ̈

of the meeting.

5 Future Plans

In 2014, Metsahovi is scheduled to participate in three  ̈

EUROPE sessions and four T2 sessions. Minttu Uunila

will be EVN VLBI and technical friend for Metsahovi  ̈

starting from January 2014 and will be in charge of all

VLBI observations at Metsahovi Radio Observatory.  ̈

The DBBC boards will be repaired in January 2014.

Acknowledgements

FGI and Metsahovi teams acknowledge support from  ̈

the Academy of Finland (grant number 135101).

References

1. U. Kallio and N. Zubko. The effect of the systematic error

in the axis offset value on the coordinates estimated in VLBI

data analysis. Proceedings of the 21th Meeting of the EVGA,

edited by N. Zubko and M. Poutanen, p. 237-241, 2013.

IVS 2013 Annual Report
VERA 2013 Geodetic Activities

Takaaki Jike, Yoshiaki Tamura, Makoto Shizugami

Abstract The geodetic activities of VERA in the

year 2013 are briefly described. The regular geodetic observations are carried out both in K- and S/Xbands. The frequency of regular observations are three

times a month—twice for the VERA internal observations in K-band. The networks of the S/X sessions

are JADE of GSI and IVS-T2. The raw data of the

T2 and JADE sessions are electronically transferred

to the Bonn, Haystack, and GSI correlators via Internet. Gravimetric observations are carried out at the

VERA stations. Superconducting gravimeters installed

at Mizusawa and Ishigakijima in order to monitor precise gravity change, and the observations continued

throughout this year. The crustal movements generated

by the 11-March-2011 earthquake off the Pacific coast

of Tohoku continued during 2013, and displacement of

the VERA-Mizusawa position by post-seismic creeping continued.

1 General Information

VERA is a Japanese domestic VLBI network consisting of the Mizusawa, Iriki, Ogasawara, and Ishigakijima stations. Each station is equipped with a 20-m radio telescope and a VLBI backend. The VERA Mizusawa 20-m antenna is shown on the left in Figure 1.

The small antenna on the right is the Mizusawa 10-m

antenna. The VERA array is controlled from the Array

Operation Center (AOC) at Mizusawa via Internet.

Mizusawa VLBI Observatory, National Astronomical Observatory of Japan

VERA Network Station

IVS 2013 Annual Report

Fig. 1 VERA Mizusawa 20-m antenna (left) and 10-m antenna.

The primary scientific goal of VERA is to reveal the

structure and the dynamics of our galaxy by determining three-dimensional force field and mass distribution.

Galactic maser sources are used as dynamical probes,

the positions and velocities of which can be precisely

determined by phase referenced VLBI relative to extragalactic radio sources. The distance is measured as a

classical annual trigonometric parallax. The observing

frequency bands of VERA are S and X, K (22 GHz),

and Q (43 GHz). Geodetic observations are made in

S/X- and K-bands. Q-band is currently not used for

geodesy. Only a single beam is used even in K-band

in geodetic observations, although VERA can observe

two closely separated (0.2

◦ < separation angle < 2.2◦

)

radio sources simultaneously by using the dual beam

platforms.

General information about the VERA stations is

summarized in Table 1, and the geographic locations

are shown in Figure 2. The lengths of the baselines

range from 1000 km to 2272 km. The skyline at Ogasawara station ranges from 7◦

to 18◦ because it is located at the bottom of an old volcanic crater. The northeast sky at Ishigakijima station is blocked by a nearby

139
140 Jike et al.

high mountain. However, the majority of the skyline is

below 9◦. The skylines at Mizusawa and Iriki are low

enough to observe sources with low elevation. Since

Ogasawara and Ishigakijima are small islands in the

open sea and their climate is subtropical, the humidity in the summer is very high. This brings about high

system temperatures in the summer, in particular in K

and Q bands. These stations and Iriki station are frequently hit by strong typhoons. The wind speed sometimes reaches up to 60–70 m/s.

Fig. 2 Distribution of the stations in the VERA Network.

Table 1 Location.

Site name Longitude Latitude Altitude

Mizusawa 141◦ 07’ 57”.199 E 39◦ 08’ 00”.726 N 75.7 m

Iriki 130◦ 26’ 23”.593 E 31◦ 44’ 52”.437 N 541.6 m

Ogasawara 142◦ 12’ 59”.809 E 27◦ 05’ 30”.487 N 223.0 m

Ishigakijima 124◦ 10’ 15”.578 E 24◦ 24’ 43”.834 N 38.5 m

2 Current Status

Parameters of the antennas and front- and back-ends

are summarized in Tables 2 and 3, respectively. Two

observing modes are used in geodetic observations.

One is the VERA internal observation in K-band with

the recording rate of 1 Gbps. The other is the conventional S/X-band observation with K5-VSSP. JADE,

which is GSI’s domestic observation project, and IVST2 sessions belong to this class. Only Mizusawa and

Ishigakijima participated in these sessions.

Table 2 Antenna parameters.

Diameter of main reflector 20-m

Mount type AZ-EL

Surface accuracy 0.2mm (rms)

Pointing accuracy <12”(rms)

Azimuth Elevation

Slew range -90◦ – 450◦ 5

◦ – 85◦

Slew speed 2.1◦/sec 2.1◦/sec

Acceleration 2.1◦/sec2 2.1◦/sec2

S X K

HPBW 1550” 400” 150”

Aperture efficiency 0.25 0.4 0.47

Table 3 Front-end and back-end parameters.

Front-end parameters

Frequency band S X K

Frequency range (GHz) 2.18–2.36 8.18–8.60 21.5–24.5

Receiver temperature >100 ◦K 100 ◦K 39±8

◦K

Polarization RHC RHC LHC

Receiver type HEMT HEMT cooled HEMT

Feed type Helical array Horn

Back-end parameters

Observation type VERA T2 and JADE

channels 16 16

Bandwidth/channel 16MHz 4MHz

Filter Digital Analog video band

Recorder DIR2000 K5VSSP

Recording rate 1 Gbps 128 Mbps

Deployed station 4 VERA Mizusawa, Ishigakijima

3 Staff

Noriyuki Kawaguchi is the director of Mizusawa VLBI

Observatory. The geodesy group consists of Yoshiaki Tamura (scientist), Takaaki Jike (scientist), and

Makoto Shizugami (engineer).

4 Activities during the Past Year

VERA observes seven days a week, except for a maintenance period in June and July. The 24-hour geodetic

sessions are allocated twice or three times in a month.

Among these geodetic sessions, VERA internal geodetic observations in K-band are performed once or twice

in a month, and Mizusawa and Ishigakijima participate

in JADE by GSI or IVS-T2 sessions in S/X-band on a

once-a-month basis. The main purpose of the VERA

IVS 2013 Annual Report
VERA 2013 Report 141

internal geodetic observations is to determine relative

positions of the VERA antennas accurate enough for

astrometric requirements. The purpose of the S/X sessions is to make the VERA coordinates refer to the IVS

reference frame.

In VERA internal geodetic sessions, the regularlyused frequency changed from S/X-band to K-band in

2007. The reason for the shift of the observing frequency band from S/X-band to K-band is to avoid the

strong radio interference by mobile phones in S-band,

particularly at Mizusawa. The interfering signal which

has line spectra is filtered out. However, this filtering considerably degrades the system noise temperature. The interference zone is increasing, so it is likely

that S-band observations will become impossible in the

near future. On the other hand, VERA has the highest

sensitivity in K-band as shown in Table 3. Thanks to

the high sensitivity in this band, the maximum number

of scans in K-band is 800/station/24-hours while that

in S/X-band is 500 at most. It has been confirmed that

the K-band observations are far more precise. In fact,

standard deviations of the individual determinations of

the antenna positions in K-band are less than half of

those in S/X-band.

In 2013, the long maintenance period from the beginning of June to the middle of August was allocated.

Except for this period, VERA carried out regular VLBI

observations. We participated in seven T2 sessions and

in four JADE sessions.VERA internal geodetic observations were carried out 16 times. The final estimation

of the geodetic parameters was derived by using the

software developed by the VERA team.

Continuous GPS observations were carried out at

each VERA station throughout the year. The superconducting gravimeter (SG) installed within the enclosure

of the Mizusawa VLBI observatory, in order to accurately monitor gravity change for the purpose of monitoring height change at the VERA Mizusawa station,

continued acquisition of gravity data. Four water level

gauges surrounding the SG were used for monitoring

the groundwater level. The preliminary results show

that gravity variation due to the variation of the water table can be corrected as accurately as the 1 micro

gal level. An SG was newly installed also in the VERA

Ishigakijima station, and observations were started in

January 2012. The observations continued also during 2013. This observing aims at solving the cause of

the slow slip event which occurs frequently around the

Ishigaki island.

5 State of the Crustal Movement after the

11-Mar-2011 Earthquake at Mizusawa

After the 2011 earthquake off the Pacific coast of

Tohoku (Mw=9.0) [Epoch=11 March 2011, 14:16:18

JST], VERA-Mizusawa was displaced by co-seismic

crustal movement and post-seismic creeping. Also

during 2013, the creeping continued, although the

speed declined. According to the newest analysis, the

co-seismic steps are X=-2.013 m, Y=-1.380 m, and

Z=-1.072 m, and the displacement by creeping during

2013 is X= -0.110 m, Y= -0.089 m, and Z= -0.036 m.

6 Future Plans

Currently, the examination into increasing the recording rate from 1 Gbps to 4 Gbps with direct sampling

(OCTAD) is being carried out. The reconstruction accompanying this specification change is planned also

at SX system. Furthermore, the examination of changing the recording system from tape recorder to HDD

(OCTADISK) is also in force. With these changes, the

operation of the new software correlation system (OCTACOR2) is due to become regular.

IVS 2013 Annual Report
Noto Station Status Report

Gino Tuccari

Abstract The Noto VLBI station was fully operational

in 2013. Important progress was achieved in the

technological and instrumentation area. A great effort

was made to develop and realize VGOS (formerly

VLBI2010) compatible front- and back-end systems.

The fast connection at 10 Gbps was installed.

1 Antenna and Receivers

The mechanical parts for the frequency agility installation in the antenna are ready and will be transferred to

the Noto site at the beginning of 2014. The installation

is planned to be after the first EVN session in 2014,

when the company specialized for this type of operations will be available to visit Noto. The new VGOS

broadband DBBR receiver operating in the range of 1-

16 GHz is progressing. The feed and cryogenic sections were completed. The choice of possible frontend LNAs is under evaluation. This receiver was developed to operate on a typical 12-meter VGOS antenna

and will be adapted to the Noto 32-m radio telescope,

making use of a tertiary mirror operating in the vertex room. The receiver after appropriate amplification

of the entire broadband is operating entirely in the digital domain. It indeed is part of the DBBC3 system,

even though it can be operated also in an independent

environment. The two receivers operating in the range

of 80-100 GHz for the secondary focus and purchased

from IRAM will not be installed for now in the antenna

Istituto di Radioastronomia INAF, Noto

Noto Network Station

IVS 2013 Annual Report

because of a lack of funds. Indeed a dedicated tertiary

mirror for properly focusing the beam is necessary as

the replacement of the existing secondary mirror. Waiting for the proper financing one such receiver will be

adapted for measuring the atmospheric transparency,

with the help of a small antenna and a pointing structure, providing that a dedicated local oscillator can be

realized with the existing resources.

2 H-maser

The new maser was installed in October, while the old

EFOS-5 was modified to be kept active in parallel with

the new one. Additional equipment is going to be installed in order to have a continuous comparison between the two atomic clocks.

3 e-VLBI

The connection at 10 Gbps was activated in October

2013. Nowadays in the station e-VLBI observations at

1 Gbps are routine operations.

4 DBBC

The DBBC2 system is now active as the main VLBI

backend even if the system is still not fully complete

for VLBI2010. A full implementation is expected in

the next months. Since autumn all the observations,

including the EVN session, have been observed with

142
Noto 2013 Report 143

this terminal. The Ethernet interface FILA10G is now

available, so having the 10 G connection available, 4

and 8 Gbps e-VLBI experiments are today possible

with Noto.

The DBBC3 project, a collaboration of IRA (Italy)

- MPI (Germany) - (OSO) Sweden, is progressing as

expected in the scheduled time. The main parts that

have been realized are: the sampler ADB3, operating

at 4 GHz bandwidth, and the CORE3 board, able to

process pieces of the same bandwidth in DDC and PFB

mode. The FILA40G unit has been assembled. Its functionality is to receive multiple 10G connections coming

from the output of the CORE3 boards and handling the

data Ethernet packets for different functionalities. One

of them is the recording capability at 32 Gbps. A first

DBBC3 unit will be tested in Noto during 2014 with

the DBBR receiver. Figure 1 and Figure 2 show a stack

of ADB3 and CORE3, and a FILA40G, respectively.

5 Observations

During 2013, 12 geodetic experiments have been observed: CRF73, EUR121, EUR122, CRF74, EUR123,

EUR124, CRF75, T2091, EUR125, T2092, EUR126,

and T2094.

IVS 2013 Annual Report
144 Tuccari

Fig. 1 Stack of DBBC3 boards for dual polarization.

Fig. 2 FILA40G.

IVS 2013 Annual Report
Ny-Alesund Geodetic Observatory 2013 Annual Report  ̊

Moritz Sieber

Abstract In 2013, the 20-m telescope at Ny-Alesund,  ̊

Svalbard, operated by the Norwegian Mapping Authority (NMA), took part in 209 out of 211 scheduled sessions of the IVS program.

1 General Information

The Geodetic Observatory of the Norwegian Mapping

Authority (NMA) is situated at 78.9◦ N and 11.9◦ E in

Ny-Alesund, in Kings Bay, at the west side of the island  ̊

Spitsbergen. This is the biggest island in the Svalbard

archipelago. In 2013, Ny-Alesund was scheduled for  ̊

125 24-hour VLBI sessions, including R1, R4, EURO,

RD, T2, and RDV sessions, and 86 one-hour sessions

within the Intensives-program.

In addition to the 20-meter VLBI antenna, the

Geodetic Observatory has two GNSS antennas in the

IGS system and a Super Conducting Gravimeter in the

Global Geodynamics Project (GGP) installed at the

site. A second gravimeter (a GWR “iGrav”) got set

up in September and will replace the former system

after a period of parallel measurements. The FrenchGerman AWIPEV research base in Ny-Alesund  ̊

operates a DORIS station. In October 2004, a GISTM

(GPS Ionospheric Scintillation and TEC Monitor)

receiver was installed at the Mapping Authority’s

structure in the frame of ISACCO, an Italian research

project on ionospheric scintillation observations, led

by Giorgiana De Franceschi of the Italian Institute

Norwegian Mapping Authority, Geodetic Institute

NYALES20 Network Station

IVS 2013 Annual Report

Fig. 1 Telescope seen from east.

of Volcanology and Geophysics (INGV). Another

Real-Time Ionospheric Scintillation (RTIS) Monitor

was set up by the NMA in November 2012.

1.1 Component Description

The antenna with 20-m diameter is intended for geodetic use and receives in S- and X-band. Its design and

construction are similar to those at Green Bank and Kokee Park. A rack with 14 video-converters, Mark IV

decoder, and Mark 5 sampler streams the data to a

Mark 5B+ recorder. A Mark 5A-unit is used to transfer data via network to the correlators. Timing and frequency is provided by a NASA NR maser, which is

monitored by a CNS system.

145
146 Sieber

1.2 Staff

The staff at Ny-Alesund consists of four people em-  ̊

ployed at 75 %, which means that three full-time positions are covered (see Table 1 for an overview). Each

position goes with a three-year contract that can be extended up to 12 years, but in average people stay 3–

4 years. The observatory is part of the Geodetic Division of the Norwegian Mapping Authority with its

main office at Hønefoss (near Oslo).

During 2013, Asmund Skjæveland moved back to  ̊

the mainland to the love he found—all the best wishes

for the two of you. He is still within reach however,

working at the NMA’s control center for the SATREFnetwork. His open position was covered by Susana

Garc ́ıa-Espada, who was previously working at the station in Yebes, and she brought some sun and Spanish

air to Ny-Alesund. Welcome to the Arctic!  ̊

Table 1 Staff related to VLBI operations at Ny-Alesund.  ̊

Hønefoss Section Manager Reidun Kittelsrud

Technical Manager Leif Morten Tangen

Ny-Alesund  ̊ Station Manager Moritz Sieber

Engineer Susana Garc ́ıa-Espada

(≥ Sept.)

Engineer Geir Mathiassen

Engineer Kent Roskifte

Engineer Asmund Skjæveland  ̊

(≤ May)

2 Current Status and Activities

2.1 Maintenance

The main bearings in one of the Az-gearboxes showed

wear; as well, the top radial shaft seal was broken, leading to both oil leakage and water contamination of the

lubrication system. So the whole gearbox was replaced

during the maintenance period in summer, which had

to be extended by one week. Everything worked well,

and the gearbox that was taken down will be overhauled to provide a working spare one again.

2.2 Monitoring

The monitoring system has been extended by the ability to send alerts by VHF radio (see Figure 2 for a

flowchart). Due to the situation in Ny-Alesund (be-  ̊

ing in a small village without mobile phone coverage

and living and working at the same place) this was

preferred to sending e-mails or short-messages. The

watchdog runs as a cron-job on the Field System computer. It checks if the Field System is running and asks

for the current logfile-name. This is the only interaction

between these two processes; once the logfile is known,

the data since the last run is searched for keywords and

figures such as:

• receiver 20K/70K temperature levels

• Dewar pressure

• Helium supply pressure

• wind speed

• Field System error codes <cc>,-<nnn>

If one of the values exceeds a threshold or an error code

matches one on a predefined list, either a warning or

alarm message is broadcast via VHF. Once received on

the operators’ radio it triggers an alarm.

watchdog

MET−data

Fieldsystem

receiver

parameter

current

logfile

VHF−alarm

Fig. 2 VHF alerting system.

In combination with the e-control software by

A. Neidhardt et al., this is an excellent tool to react

quickly even at night, thus making night shifts unnecessary and enabling operators to work together during

ordinary working hours (sharing knowledge) instead

of going on separate shifts.

IVS 2013 Annual Report
Ny-Alesund Geodetic Observatory  ̊ 147

2.3 GPS Campaign

During late August, the triennial GPS campaign was

carried out by Knut Gjerde from the Geodetic Institute,

Hønefoss. 18 bolts of the reference network around

Ny-Alesund were measured over a period of five days  ̊

each.

2.4 Session Performance

By the end of 2012, Ny-Alesund was scheduled for  ̊

121 24h- and 46 1h-sessions. By the end of 2013, 123

of 125 24h- and 86 1h-sessions were observed. The

increase in the number of 1h-Intensives is due to replacing Wettzell in the Int1 and Int2 series during their

repair between July and September. For one R1- and

one R4-session Ny-Alesund had to be taken out of the  ̊

schedule due to the extension of maintenance work; as

a compensation, three sessions during December and

one in May were added. Four of the remaining sessions

were recorded with 98% or less. A summary can be

found in Table 2.

Table 2 Sessions with trouble (that recorded 98% or less).

Session Comments

R4576 not scheduled (announced maintenance period), but in

performance matrix

RV100 interrupted observation for participation in Int1

T2091 interrupted observation for participation in Int1

RD1308 receiver warming up. stopped to cool down in time for

succeeding R4

R4606 missed some scans by troubleshooting receiver monitoring issues

R1605 does not appear in schedule statistics, but observed as

scheduled

R1606 not observed due to warm receiver

R4596 removed from schedule, extending maintenance period

2.5 New Observatory

Due to the proximity of the airfield to the current location, the new observatory has to be built further

away. A road must be built first, and due to the Arctic

and environmental conditions (removal and regrowth

of top soil), this can only happen during the “summer”

months between June and October. More than the first

half of it, including a bridge and a culvert section to

cross a riverbed, was finished in 2013, and work will

continue next year.

2.6 New Instrumentation

In September, a new GWR instrument iGrav 007

gravimeter was installed. It will replace the old

superconducting gravimeter which needed a refill with

liquid helium every now and then. The former system

will be shipped to the mainland after some months of

parallel measurements.

3 Future Plans

Ny-Alesund will participate in CONT14. Related to  ̊

that, the media pool has to be upgraded. The current

Mark IV rack will be replaced by a digital backend

system, both to replace the aged video converters and

to gain experience with the new system that will be

installed at the new site. The road construction will

continue, and first preparations on the new observatory’s site will be performed. By end of the year the

last remaining hundred miles between Ny-Alesund and  ̊

Longyearbyen will be covered by fiber cable, replacing

the current radio link. The cable is supposed to be operational in early spring 2015.

IVS 2013 Annual Report
German Antarctic Receiving Station (GARS) O’Higgins

Alexander Neidhardt 1, Christian Plotz  ̈

2

, Thomas Klugel  ̈

2

, Torben Schuler  ̈

2

Abstract In 2013, the German Antarctic Receiving

Station (GARS) O’Higgins contributed to the IVS

observing program with four observation sessions in

February. Maintenance and upgrades were made and

are in progress; e.g. the complete receiver was dismounted and shipped to Wettzell. A new replacement

dewar was finished in the labs of the observatory in

Yebes, Spain.

1 General Information

The German Antarctic Receiving Station (GARS) is

jointly operated by the German Aerospace Center

(DLR) and the Federal Agency for Cartography

and Geodesy (BKG, belonging to the duties of the

Geodetic Observatory Wettzell (GOW)). The Institute

for Antarctic Research Chile (INACH) coordinates

the activities and logistics. The 9-m radio telescope at

O’Higgins is mainly used for downloading of remote

sensing data from satellites such as TanDEM-X and

for the commanding and monitoring of spacecraft

telemetry. During dedicated campaigns in the Antarctic summer it is also used for geodetic VLBI. In 2013,

the station was again manned by DLR staff and by a

team for the maintenance of the infrastructure (e.g.

power and freshwater generation) the entire year.

BKG staff was there from January to the beginning of

March. The VLBI campaign in November—December

1. Forschungseinrichtung Satellitengeodasie (FESG), Technis-  ̈

che Universitat M ̈ unchen  ̈

2. Bundesamt fur Kartographie und Geod  ̈ asie (BKG)  ̈

GARS O’Higgins Network Station

IVS 2013 Annual Report

2013 had to be canceled again, as the VLBI receiver is

currently in Wettzell for maintenance.

Over the last few years, special flights using “Hercules C-130”-aircrafts and small “Twin Otter DHC6”-aircrafts as well as transportation by ship were organized by INACH in close collaboration with the

Chilean Army, Navy and Airforce and with the Brazilian and Uruguayan Airforce in order to transport staff,

technical material and food for the entire stay from

Punta Arenas via Base Frei on King George Island

to O’Higgins on the Antarctic Peninsula. The conditions for landing on the glacier are strongly weather

dependent and involve an increasing risk; in general,

transport of personnel and cargo is always a challenging task. Arrival and departure times strongly depend

on the climate conditions and on the logistic circumstances.

After each Antarctic winter the VLBI equipment at

the station must be initialized again. Damages resulting from the winter conditions or strong storms have

to be identified and repaired. Shipment of each kind of

material, such as spare parts or upgrade kits, has to be

carefully prepared in advance.

Besides the 9-m VLBI antenna, which is used for

the dual purposes of receiving data from and sending

commands to remote sensing satellites and performing

geodetic VLBI, other geodetically relevant instruments

are also operated upon on location:

• an H-maser, an atomic Cs-clock, a GPS time receiver, and a Total Accurate Clock (TAC) offer time

and frequency.

• two GNSS receivers both operating in the frame of

the IGS network, while one receiver is additionally

part of the Galileo CONGO network. The receivers

worked without failure.

148
GARS O’Higgins 149

Fig. 1 The Web cam image of the VLBI antenna and some realtime penguin cams from the O’Higgins Web page.

• a meteorological station providing pressure, temperature, and humidity and wind information, as

long as the temporarily extreme conditions did not

disturb the sensors.

• a radar tide gauge which was installed in 2012. The

radar sensor itself is space referenced by a GPSantenna mounted on top and Earth referenced via

the local survey network. The radar gauge is operated only during the Antarctic summer.

• an underwater sea level gauge for permanent monitoring of water pressure, temperature, and salinity.

2 Staff

The members of staff for operation, maintenance and

upgrade of the VLBI system and other geodetic devices

are summarized in Table 1.

Table 1 Staff - members of RTW.

Name Affiliation Function Mainly

working for

Torben Schuler  ̈ BKG head of the GOW GOW

(since January 2013)

Christian Plotz  ̈ BKG electronic engineer O’Higgins,

(chief engineer RTW) RTW, TTW

Christian Schade BKG geodesist O’Higgins

operator, SLR

Reiner Wojdziak BKG software engineer O’Higgins,

IVS Data Center

Leipzig

Andreas Reinhold BKG geodesist O’Higgins

operator

Thomas Klugel  ̈ BKG geologist administration

laser gyro/

local systems

Wettzell

Rudolf Stoeger BKG geodesist logistics for

O’Higgins,

GNSS

Alexander Neidhardt FESG head of the VLBI group RTW, TTW

and VLBI station chief

Gerhard Kronschnabl BKG electronic engineer TTW, RTW,

(chief engineer TTW) TIGO

3 Observations in 2013

GARS participated in the following sessions of the IVS

observing program during the Antarctic summer campaign (January-March 2013):

• IVS-OHIG82 February 11 - 12, 2013

• IVS-OHIG83 February 13 - 14, 2013

• IVS-T2088 February 19 - 20, 2013

• IVS-OHIG84 February 20 - 21, 2013

The observations were recorded with Mark 5A. The

related data modules were carried from O’Higgins to

Punta Arenas by the staff members on their way back

home. From Punta Arenas, the disk units were shipped

by regular air freight back to Wettzell and then to the

correlator in Bonn, Germany.

4 Technical Improvements and

Maintenance

The extreme environment conditions in the Antarctic

require special attention to the GARS telescope and the

infrastructure. Corrosion frequently results in problems

with connectors and capacitors. Defective equipment

needs to be detected and replaced. The antenna, the

S/X-band receiver, the cooling system, and the data acquisition system have to be activated properly. A probIVS 2013 Annual Report
150 Neidhardt et al.

lem is the low transfer rates (often with only 50 kbps)

on the communication connection, so the Internet and

phone access were reduced. Also, the Web cams are

regularly maintained.

Special maintenance tasks focused on the stabilization of the timing system, where the NTP-server is now

connected to the external PPS-signal of the Cesium

standard. The GNSS-antennas had to be cleaned from

salt debris, and the acquisition PC of the GNSS point

OHI2 was replaced by a low maintenance PC box.

The meteorological data are now directly available

on the Web pages with an update interval of one

minute. Because of some defective connectors, the

radar gauge had to be dismounted and repaired.

The construction of the new dewar is finished now

in order to replace the original O’Higgins dewar. The

current one must be evacuated permanently by a turbo

molecular pump to maintain the required vacuum due

to leakage. The new one is currently at the observatory

at Wettzell to be tested.

Fig. 2 The new dewar for the VLBI system at O’Higgins.

The dismounted receiver is currently at the observatory at Wettzell for maintenance. The idea is to fix

overaged parts and to integrate a new control equipment.

The remote control of complete VLBI sessions

could be extended. Using the newly developed

Wettzell software the O’Higgins Field System can

be controlled over a secure Internet connection from

Wettzell. This is a key feature to extend the operation

periods in GARS O’Higgins. Another technique, using

the download and commanding gaps for geodetic

VLBI, was discussed with the DLR and is planned to

be realized. But it requires a suitable communication

with the scheduling and control programs of the DLR.

A complete geodetic survey was performed with

equipment from Wettzell (total station TCA 2003) in

addition to the VLBI observations, to determine the local ties. Additional leveling surveys were included, using the equipment DNA 03.

5 Future Plans

The replacement dewar must be installed again after

the tests at Wettzell. The maintained receiver must also

be installed again. A dedicated plan should offer a

shared, interleaved observation of satellites (DLR) and

VLBI sources (BKG) during the whole year. In order

to optimize the operating procedure and the disposition

of staff, a common control room for DLR and BKG

staff is in preparation. Some antenna motors must be

replaced, and a gear needs to be inspected.

IVS 2013 Annual Report
Onsala Space Observatory – IVS Network Station Activities

During 2013

Rudiger Haas, Gunnar Elgered, Johan L  ̈ ofgren, Tong Ning, Hans-Georg Scherneck  ̈

Abstract We participated in 40 IVS sessions. As in

the previous five years, we used several of the sessions that involved both Onsala and Tsukuba to perform ultra-rapid UT1-UTC observations together with

our colleagues in Tsukuba. Additionally, we observed

two dedicated ultra-rapid sessions. The first was together with Tsukuba, Hobart, and HartRAO and aimed

at determining ultra-rapid EOP. The second was together with Tsukuba and aimed at a northern hemisphere ultra-rapid UT1-UTC determination in parallel with the AUST-13-06 session. We also performed a

short session in which we observed a GLONASS satellite using the Onsala 25-m telescope and the Wettzell

20-m telescope. The progress of the Onsala Twin Telescope (OTT) project was unfortunately delayed due to

issues concerning wildlife protection. Extensive OTT

simulation studies were performed, trying to optimize

the sky visibility from a number of possible antenna locations. An updated application for the installation was

submitted to the authorities at the end of 2013.

1 General Information

The Onsala Space Observatory is the national facility for radio astronomy in Sweden with the mission to

support high-quality research in radio astronomy and

geosciences. The observatory was established in 1949

and is located at Ra ̊o on the Onsala Peninsula on the  ̈

Swedish west coast, about 40 km south of GothenChalmers University of Technology, Department of Earth and

Space Sciences, Onsala Space Observatory

Onsala IVS Network Station

IVS 2013 Annual Report

Fig. 1 An aerial photo of Ra ̊o with the Onsala Space Observa-  ̈

tory. The white spot approximately in the center of the photo is

the 30-m diameter radome that encloses the 20-m radio telescope

which is used for geodetic VLBI observations. (Credit: Onsala

Space Observtory/Vastkustflyg, 2011)  ̈

burg. Onsala belongs to the municipality of Kungsbacka. Figure 1 shows an aerial photo of Ra ̊o. ̈

The geoscience instrumentation at Onsala includes

equipment for geodetic VLBI, GNSS, a superconducting gravimeter with a platform for visiting absolute

gravimeters, several microwave radiometers for atmospheric measurements, both GNSS based and pressure based tide gauges, and a seismometer. The Onsala

Space Observatory can thus be regarded as a fundamental geodetic station.

In the coming years, the Onsala Twin Telescope

(OTT) will be installed at the observatory and will

consist of a pair of two new antennas following the

VLBI2010 recommendations.

The staff members associated with the IVS Network Station at Onsala are listed in Table 1.

151
152 Haas et al.

Table 1 Staff members associated with the IVS Network Station at Onsala. All e-mail addresses have

the ending @chalmers.se, and the complete telephone numbers start with the prefix +46-31-772.

Function Name e-mail telephone

Responsible P.I. for geodetic VLBI Rudiger Haas rudiger.haas 5530  ̈

Observatory director Hans Olofsson (– 2013.11.30) hans.olofsson 5520

John Conway (2013.12.01 –) john.conway 5520

Head of department Gunnar Elgered gunnar.elgered 5565

Ph.D. students and postdocs Johan Lofgren johan.lofgren 5566  ̈

involved in geodetic VLBI Niko Kareinen (2013.08.19 –) niko.kareinen 5566

Tong Ning tong.ning 5578

Responsible for the Michael Lindqvist michael.lindqvist 5508

VLBI Field System Rudiger Haas rudiger.haas 5530  ̈

Responsible for the Karl-Ake Johansson karl-ake.johansson 5571  ̊

VLBI equipment Leif Helldner leif.helldner 5576

VLBI operator Roger Hammargren roger.hammargren 5551

Telescope scientist Henrik Olofsson henrik.olofsson 5564

Software engineer Mikael Lerner mikael.lerner 5581

Responsible for gravimetry Hans-Georg Scherneck hans-georg.scherneck 5556

2 Geodetic VLBI Observations

We participated in all of the 40 planned IVS sessions.

In order to gain experience with the modern digital

backends, for about 2/3 of these sessions we used

both VLBI backends at Onsala, i.e. the Mark IV and

the DBBC, and recorded in parallel on the Mark 5A

and the Mark 5B+ data acquisition systems, respectively. We asked the staff at the Bonn correlator to

do fringe-tests for these parallelly recorded sessions,

or we did zero-baseline correlation tests ourselves

with the software correlator DiFX at Onsala. There

were some difficulties in the handling of the DBBC in

the beginning, but we gained experience and learned

how to use the DBBC/Mark 5B+ system successfully.

Fringes were found with the DBBC/Mark 5B+, and

the Bonn correlator could not detect any systematic

changes w.r.t. the Mark IV/Mark 5A observations.

Several databases were produced by the Bonn correlator that include Onsala both as a Mark IV/Mark 5A

and a DBBC/Mark 5B+ station. We analyzed these

databases and could not find any significant effects on

the geodetic results due to the type of backend and

recording system. As a consequence we decided on

a smooth transition to the DBBC/Mark 5B+ VLBI

system for regular IVS production in the fall of 2013.

In addition to the 40 regular IVS sessions, we also

observed two dedicated ultra-rapid sessions, a fourstation session UR-13-01 together with Tsukuba, Hobart, and HartRAO, and a one-baseline session UR-13-

03 together with Tsukuba.

Furthermore, we did a test experiment together with

Wettzell to observe signals from the GLONASS satellites.

3 Monitoring Activities

We continued with the monitoring activities as described in previous annual reports:

Vertical height changes of the telescope tower.

We continued to monitor the vertical height

changes of the telescope tower using the invar rod system at the 20-m telescope. The measurements are available at http://wx.oso.chalmers.se/pisa/.

Calibration of pressure sensor.

We continued to calibrate the Onsala pressure

sensor using a Vaisala barometer borrowed from the

Swedish Meteorological and Hydrological Institute

(SMHI). This instrument was installed at Onsala in

late 2002 and has been calibrated at the SMHI main

facility in Norrkoping every one to two years since  ̈

then. The latest calibration was on October 11, 2011.

Since the installation of a new VLBI pressure sensor

in 2008 the agreement between the Onsala VLBI

pressure and the pressure read by the calibrated sensor

is on the level of ±0.1 hPa.

IVS 2013 Annual Report
OSO – IVS Network Station 153

Table 2 Geodetic VLBI observations at Onsala during 2013. Information is given on which VLBI backend was used, whether data

were e-transferred in real-time (RT) and/or off-line (OL) and to which correlator, whether modules were shipped to a correlator,

and whether Ultra-rapid UT1-UTC results were produced. The last column gives some general remarks and information on the

percentage of the scheduled Onsala observations that were used in the analysis (as reported in the Web pages for the IVS session

analyses), compared to the station average percentage per experiment.

Exper. Date VLBI-backend E-transfer Module Ultra-rapid General remarks and % of scheduled observations used in the

Mark IV DBBC RT OL shipment UT1-UTC analysis as reported in the IVS Web pages’ analysis reports.

R1-566 01.02 yes yes – Bonn – – Mark IV in production, Onsala: 93.2 % (station avg. 88.8 %)

R1-567 01.07 yes yes – Bonn – – Mark IV in production, Onsala: 96.5 % (station avg. 93.2 %)

EUR-121 01.21 yes yes – Bonn – – Mark IV in production, Onsala: 85.4 % (station avg. 70.3 %)

R1-569 01.22 yes yes Tsuk Bonn – yes Mark IV in production, Onsala: 80.2 % (station avg. 65.6 %)

G-0128 01.28 yes – – JIVE – – GLONASS observations together with Wettzell, 1 h, OK

R1-570 01.28 yes yes Tsuk Bonn – – Mark IV in production, Onsala: 91.4 % (station avg. 89.6 %)

RD-13-01 01.29 yes yes Tsuk Hays – – not correlated yet in Haystack

UR-13-01 01.30 yes – Tsuk – – yes scheduled for ultra-rapid UT1-UTC determination

R1-572 02.12 yes yes – Bonn – – Mark IV in production, Onsala: 90.5 % (station avg. 85.6 %)

R1-573 02.18 yes yes Tsuk Bonn – yes Mark IV in production, Onsala: 96.5 % (station avg. 94.4 %)

T2-088 02.19 yes – Tsuk Bonn – yes Mark IV in production, Onsala: 78.8 % (station avg. 63.2 %)

R1-578 03.25 yes – – Bonn – – Mark IV in production, Onsala: 94.7 % (station avg. 90.0 %)

R1-579 04.02 yes – Tsuk Bonn – – Mark IV in production, Onsala: 90.5 % (station avg. 85.6 %)

R1-580 04.08 yes – Tsuk Bonn – – Mark IV in production, Onsala: 94.4 % (station avg. 90.3 %)

RD-13-02 04.09 yes – – Hays – – Mark IV in production, Onsala: 95.2 % (station avg. 92.8 %)

R1-582 04.22 yes – Tsuk Bonn – – Mark IV in production, Onsala: 96.5 % (station avg. 94.7 %)

EUR-123 05.06 yes yes – Bonn – – Mark IV in production, Onsala: 82.8 % (station avg. 72.6 %)

R1-585 05.13 yes yes – Bonn – – Mark IV in production, Onsala: 94.1 % (station avg. 90.1 %)

RD-13-03 05.14 yes yes – Hays – – Mark IV in production, Onsala: 92.5 % (station avg. 87.3 %)

R1-591 06.24 yes yes – Bonn – yes Mark IV in production, Onsala: 97.3 % (station avg. 94.3 %)

T2-090 06.25 yes yes Tsuk Bonn – yes Mark IV in production, Onsala: 72.9 % (station avg. 52.4 %)

R1-592 07.01 yes yes Tsuk Bonn – yes Mark IV in production, Onsala: 94.3 % (station avg. 93.0 %)

EUR-124 07.04 yes yes – Bonn – – Mark IV in production, Onsala: 83.4 % (station avg. 71.1 %)

R1-598 08.12 yes yes Tsuk Bonn – – Mark IV in production, Onsala: 92.7 % (station avg. 79.0 %)

R1-599 08.19 yes yes – Bonn – – Mark IV in production, Onsala: 71.7 % (station avg. 58.9 %)

RD-13-06 08.21 yes yes Tsuk Hays – – Mark IV in production, Onsala: 79.2 % (station avg. 70.7 %)

R1-600 08.26 yes yes – Bonn – – Mark IV in production, Onsala: 58.8 % (station avg. 48.0 %)

EUR-125 09.02 yes yes – Bonn – – Mark IV in production, Onsala: 64.6 % (station avg. 46.3 %)

R1-601 09.03 yes yes – Bonn – yes Mark IV in production, Onsala: 95.5 % (station avg. 92.8 %)

R1-602 09.09 yes yes – Bonn – yes Mark IV in production, Onsala: 86.0 % (station avg. 79.3 %)

RDV-101 09.11 yes – – – Socc – Mark IV in production, Onsala: 86.2 % (station avg. 69.2 %)

R1-604 09.24 yes yes – Bonn – yes Mark IV in production, Onsala: 67.0 % (station avg. 52.2 %)

T2-092 10.01 yes – – Bonn – yes Mark IV in production, Onsala: 66.6 % (station avg. 55.8 %)

RD-13-08 10.02 yes – – Hays – yes Mark IV in production, Onsala: 81.1 % (station avg. 82.9 %)

R1-606 10.07 yes – – Bonn – yes Mark IV in production, Onsala: 69.5 % (station avg. 57.2 %)

R1-612 11.18 yes yes – Bonn – yes Mark IV in production, Onsala: 81.8 % (station avg. 68.7 %)

T2-093 11.19 yes yes – Bonn – yes DBBC in production, Onsala: 38.8 % (station avg. 26.9 %)

UR-13-06 12.05 yes – Tsuk – – yes scheduled for ultra-rapid UT1-UTC determination

R1-615 12.09 yes yes Tsuk Bonn – yes Mark IV in production, Onsala: 92.5 % (station avg. 88.2 %)

RDV-102 12.11 yes – – – Socc – Mark IV in production, Onsala: 85.9 % (station avg. 55.4 %)

R1-616 12.16 yes yes Tsuk Bonn – yes DBBC in production, Onsala: 92.5 % (station avg. 88.2 %)

T2-094 12.17 yes yes – Bonn – yes not correlated yet in Bonn

RD-13-10 12.18 yes – – Hays – yes Mark IV in production, Onsala: 87.1 % (station avg. 77.6 %)

IVS 2013 Annual Report
154 Haas et al.

2004 2006 2008 2010 2012 2014

−1

−0.8

−0.6

−0.4

−0.2

0

0.2

0.4

0.6

0.8

1

Time, Year

Difference in Pressure, hPa

VLBI(NASA/Setra) − SMHI(Vaisala)

VLBI(Vaisala) − SMHI(Vaisala)

Fig. 2 Time series of pressure differences between the VLBI

pressure sensors and the calibrated pressure sensor from SMHI.

Microwave radiometry.

The water vapor radiometer Konrad was in

operation continuously observing in a so-called skymapping mode. The second water vapor radiometer,

Astrid, was operated in the winter, but its 31 GHz

channel malfunctioned since the spring. Thus, during

cloudy conditions (liquid water drops in the atmosphere) less useful data were acquired with Astrid after

that.

Sea-level monitoring.

The GNSS-based tide gauge was operated continuously. A tide gauge based on pressure sensors was operated next to it throughout the year. In August an additional new bubbler sensor was installed at a new tidegauge site under development at a distance of approximately 300 m from the GNSS/pressure-sensor site.

Superconducting gravimetry.

The superconducting gravimeter operated continuously and produced a highly precise record of

gravity variations. Near real-time analysis results

of the superconducting gravimeter are continuously

updated at http://holt.oso.chalmers.se/

hgs/SCG/monitor-plot.html.

Absolute gravimetry.

We supported a visiting absolute gravity measurement campaign by Lantmateriet, the Swedish mapping,  ̈

cadastral, and land registration authority.

Seismological observations.

The seismometer owned by Uppsala University and

the Swedish National Seismic Network (SNSN) was

operated throughout the year.

4 A New Onsala Tide Gauge Station

We signed a contract with SMHI to install an official

SMHI tide gauge station at the observatory. This new

tide gauge will have several sensors, e.g. one radar and

two bubbler sensors for the sea-level observations. In

addition these data will be complemented by several

temperature and salinity sensors. Figure 3 depicts an

artist’s impression of this planned tide gauge site.

Fig. 3 An artist’s impression of the future SMHI tide gauge station at the Onsala Space Observatory.

5 Future Plans

• For 2014 we plan to observe a total of 50 IVS

sessions, including the CONT14 campaign. Most

likely there will, however, be an interruption in the

observations after the summer. The original radome

enclosing the 20-m telescope, installed in 1975, has

aged and will be replaced by a new one.

• We strive to operate most of the IVS sessions as

ultra-rapid UT1-UTC sessions, together with our

colleagues at Tsukuba, Hobart, and HartRAO. This

includes the CONT14 campaign.

• We will use the digital VLBI system, i.e. the DBBC

and the Mark 5B+, for all the sessions for which

this is possible. The old Mark IV VLBI system will

be decommissioned in the spring of 2014.

• We will continue the usual monitoring activities at

the observatory, and we plan to perform a new local

tie measurement.

• As mentioned above a new tide gauge station will

be installed, and the Onsala Twin Telescope project

will be officially started when all necessary permissions have been received from the authorities.

IVS 2013 Annual Report
Korea Geodetic VLBI Station, Sejong

Yi Sangoh, Ahn Kiduk, Oh Hongjong, Han Sangcheol

Abstract This report summarizes activities of Sejong

station as an IVS network station during 2013.

1 General Information

The station is located about 120 km south of Seoul,

in the middle of Sejong city, which serves as a new administrative capital. The Sejong antenna is 22 meters in

diameter, and its slew speed is 5◦/sec in both azimuth

and elevation. Its specification was designed with consideration for the possible additional set up of small antennas in the future. Sejong has set up a simultaneous

multi frequency band (S/X, K, and Q) receiving system. The S/X system can cover regular IVS sessions,

and the K,Q system can use the Korean Geodetic VLBI

Network with KVN (Korean VLBI Network managed

by the Korea Astronomy and Space Science Institute).

National Geographic Information Institute (NGII,

http://ngii.go.kr) manages the observatory, and Table 1

shows the staff members of the Sejong station. A newly

appointed site director, Mr. Ahn Ki Duk, joined us in

November 2013.

2 Sejong VLBI System

The Sejong VLBI configuration is listed in Table 2.

The antenna is Cassegrain shaped, and the 22-m main

reflector consists of 200 rectangular aluminum panels.

National Geographic Information Institute

Sejong Network Station

IVS 2013 Annual Report

Fig. 1 Layout of the VLBI 22-m antenna, monument pillars 1 to

4, GNSS and UCP (Unified Control Point).

Table 1 Staff members of the Sejong station.

Name Function e-mail

Ahn Kiduk Site Director akd8@korea.kr

Yi Sangoh S/W engineer sangoh.yi@korea.kr

Oh Hongjong H/W engineer stockoh11@korea.kr

Han Sangcheol Antenna system hsc4907@korea.kr

Each panel has four elevation adjustments at the edge

of the panel, so that the antenna main reflector surface

can be properly arranged.

155
156 Yi et al.

Table 2 Sejong antenna parameters.

Parameters Sejong VLBI

IVS letter codes Sejong (Kv)

CDP number 7368

DOMES number 23907S001

Location 127◦18′E, 36◦31′N

Elevation 177m

Diameter of main reflector 22m

Antenna type Shaped Cassegrain

Reflector surface accuracy 86μm

Operation range AZ: ±270◦

EL: 0 to 90◦

Slew speed 5

◦/sec (AZ and EL)

FS Version 9.10.4

Data acquisition Rack/Recorder K4/K5

3 2013 Activities

3.1 Fringe Tests with Tsukuba Antenna

The Sejong antenna carried out several fringe tests

with the Tsukuba antenna. We estimated the SEFDs

(S: about 30000 / X:2500) of the Sejong antenna with

several fringe tests. Its operation has been stopped by

work to improve the S-band peformance to the required

level.

3.2 X-band VLBI Observation with one of

the KVN (Korean VLBI Network)

Antennas

KASI constructed the KVN of three VLBI antennas.

An X-band receiver was installed at the Ulsan station;

it proceeded to make a fringe test and a pulsar observation with the Sejong station. The data were transferred

to KJCC at KASI.

3.3 H-maser Repair

The DAC20 and cable were replaced and repaired, because we found an error in their reference values during

inspection of the H-maser.

3.4 Antenna Motor Controller Repair

An operational failure was found in the four motor

controllers for the az/el drive. As a countermeasure

for that, one device was delivered to the manufacturer,

and it was repaired by them. We have repaired one at

present. The full repair is expected to be completed in

2014.

3.5 Filter Exchange

The existing filter frequency was changed to minimize

RFI signals in S-band (original: 2.22 Ghz to 2.37 Ghz,

new: 2.2 Ghz to 2.3 Ghz).

3.6 Monitoring System

A VLBI monitoring system was installed to allow continuous monitoring of the receiver and back-end device.

4 KASI’s SLR Installation Plan

KASI developed an SLR system with a 40 cm telescope

in 2012. It will be installed at a place very near to the

Sejong observatory. Co-location with VLBI, GNSS,

and SLR can be possible at Sejong observatory.

IVS 2013 Annual Report
Sejong Station 157

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IVS 2013 Annual Report
Sheshan VLBI Station Report for 2013

Zhiqiang Shen,Qingyuan Fan,Qinghui Liu,Xiaoyu Hong,Bo Xia

Abstract This report summarizes the observing activities at the Sheshan station (SESHAN25) in 2013.

It includes the international VLBI observations for astrometry, geodesy, and astrophysics, as well as domestic observations for satellite monitoring. We also report

on updates to and development of the facilities at the

station.

1 General Information

The Sheshan VLBI station (“SESHAN25”) is located

at Sheshan, 30 km west of Shanghai. It is hosted by

the Shanghai Astromomical Observatory (SHAO),

Chinese Academy of Sciences (CAS). A 25-meter

radio telescope is in operation at 1.3, 3.6/13, 5, 6,

and 18 cm wavelengths. The Sheshan VLBI station

is a member of the IVS and EVN. The SESHAN25

telescope takes part in international VLBI experiments

for astrometric, geodetic, and astrophysics research.

Apart from its international VLBI activities, the

telescope spent a large amount of time on the Chinese

Lunar Project, including the testing before the launch

of the Chang’e-3 satellite and the tracking campaign

after the launch of Chang’e-3.

Shanghai Astronomical Observatory, CAS

Sheshan Network Station

IVS 2013 Annual Report

2 VLBI Observations in 2013

In 2013, SESHAN25 participated in 38 IVS sessions

(including 25 INT3 Intensive sessions). SESHAN25

also participated in the EVN sessions in February,

June, and October. We participated in the R1601

session instead of the R1600 session due to an antenna

motor problem. In order to participate in the Chinese

Chang’e-3 Lunar Project, SESHAN25 observed the

Chang’e-3 satellite with a long term routine VLBI

tracking model for two or three days per week. We

missed the sessions of J13273 due to a receiver

problem.

3 Development and Maintenance of the

Sheshan Telescope in 2013

We have upgraded the Mark 5B+ Firmware Version to

16.31 (API 11.25, SDK 9.2).

4 The Staff of the Sheshan VLBI Station

Table 1 lists the group members of the Sheshan VLBI

Station. The staff are involved in the VLBI program at

the station with various responsibilities.

158
Report of Sheshan Station 159

Table 1 The staff of the Sheshan VLBI Station.

Name Background Position and Duty Contact

Xiaoyu HONG Astrophysics Director, Astrophysics xhong@shao.ac.cn

Zhiqiang SHEN Astrophysics Head of VLBI Division zshen@shao.ac.cn

Qingyuan FAN Ant. control Chief Engineer, Antenna qyfan@shao.ac.cn

Zhuhe XUE Software Professor, FS zhxue@shao.ac.cn

Quanbao LING Electronics Professor, VLBI terminal qling@shao.ac.cn

Tao AN Astrophysics Astrophysics antao@shao.ac.cn

Bin LI Microwave Technical friend, receiver bing@shao.ac.cn

Bo XIA Electronics VLBI friend, VLBI terminal bxia@shao.ac.cn

Li FU Ant. mechanics Engineer, Antenna fuli@shao.ac.cn

Jinqing WANG Electronics Engineer, Antenna jqwang@shao.ac.cn

Lingling WANG Software Engineer, VLBI terminal llwang@shao.ac.cn

Rongbing ZHAO Software Engineer, VLBI terminal rbzhao@shao.ac.cn

Weiye ZHONG Microwave Engineer, receiver wyzhong@shao.ac.cn

Jin YUAN Microwave Engineer, receiver wyzhong@shao.ac.cn

Xiuting ZUO Software Engineer, Antenna zxt@shao.ac.cn

Wei GOU Electronics Engineer gouwei@shao.ac.cn

Linfeng YU Electronics Engineer lfyu@shao.ac.cn

Yongbin JIANG Electronics Engineer jyb@shao.ac.cn

Yunxia SUN HVAC Engineer, Refrigeration sunyunxia@shao.ac.cn

Xiaocong WU Electronics Engineer wuxc@shao.ac.cn

Wen GUO Electronics Engineer gw@shao.ac.cn

5 Outlook

In 2014 the Sheshan radio telescope will take part in

26 IVS sessions and three EVN sessions. The telescope

will regularly monitor the Chang’e-3 satellite in its lunar orbit in 2014.

IVS 2013 Annual Report
The Simeiz Fundamental Geodynamics Area

A. E. Volvach, G. S. Kurbasova

Abstract This report gives an overview about the astrophysical and geodetic activities at the the fundamental geodynamics area Simeiz-Katsively. It also summarizes the wavelet analysis of the ground and satellite

measurements of local insolation on the “Nikita garden” of Crimea.

1 General Information

The Radio Astronomy Laboratory of the Crimean Astrophysical Observatory with its 22-m radio telescope

is located near Simeiz, 25 km to the west of Yalta. The

Simeiz geodynamics area consists of the radio telescope RT-22, two satellite laser ranging stations, a permanent GPS receiver, and a sea level gauge. All these

components are located within 3 km (Figure 1).

RT-22, the 22-meter radio telescope, which began

operations in 1966, is among the five most efficient

telescopes in the world.

Various observations in the centimeter and millimeter wave ranges are being performed with this telescope now and will be performed in the near future.

First VLBI observations were performed in 1969 on the

Simeiz (RT-22) to Green Bank (RT-43, USA) intercontinental baseline. RT-22 is equipped with radiometers

at the 92 cm, 18 cm, 13 cm, 6 cm, 3.5 cm, 2.8 cm, 2.3

cm, 2.0 cm, 13.5 mm, and 8 mm wavelengths.

Radio Astronomy Lab of Crimean Astrophysical Observatory

Simeiz Network Station

IVS 2013 Annual Report

2 Activities during the Past Year and

Current Status

During the past year, the Space Geodesy and Geodynamics stations regularly participated in the International Network programs — IVS, the International

GPS Service (IGS), and the International Laser Ranging Service (ILRS).

During the period 2013 January 1 through 2013

December 31, the Simeiz VLBI station participated

in 14 24-hour geodetic sessions. Simeiz regularly

participated in the EUROPE and T2 series of geodetic

sessions.

2.1 Multi-Frequency Molecular Line

Observations

Study of the star-forming regions in molecular lines

started in 1978. Two main types of observation are carried out at the radio telescope:

1) observations of maser sources (hydroxyl masers,

water masers, and SiO masers) at the frequencies of

1.6 GHz, 4.8 GHz, 22 GHz, and 86 GHz.

2) observations of millimeter molecular emission at the

frequency range from 85 GHz to 115 GHz.

The radio telescope is equipped with high-sensitive

cryogenic receivers with the noise temperatures of: 1)

30 K at 22 GHz; 2) 39 K at 4.8 GHz; 3) 70 K at frequencies from 85 GHz to 115 GHz. At the 3 mm wavelength

and with a beam width of 40 arcsecs, the effective aperture area of the antenna is 100 m

2

. The spectrum analyzers for line observations are 1) a 128 channel filter

160
Simeiz VLBI Station 161

bank spectrum analyzer with frequency band 12 MHz;

2) a digital spectrum analyzer for maser observations

with the frequency band of 4 MHz and the frequency

resolution of 8 kHz; 3) a 64 channel filter bank spectrum analyzer with a frequency band of 64 MHz.

Using the RT-22, a comet was investigated in the

OH line at the wavelength of 18 cm. Comets C/2009

R1 (McNaught) and 17P/Holmes were observed. For

comet C/2009 R1 (McNaught), we determined the

gas productivity of OH molecules as a function of

heliocentric distance. The comet-gas productivity

increases rapidly approaching perihelion [1].

2.2 The Testing of the Ground-Based

Segment of the Radioastron Mission

at Wavelengths of 1.35 cm.

In accordance with the scientific cooperation between

Ukraine and Russia a series of studies for the preparation of the operation of the ground segment of the

“RadioAstron” mission was held. Using the 22-m radio telescope RT-22 the scientific program of measurements, a substantial part of which is the study of the

compact structures in the extragalactic sources, was

prepared. For testing of the model of the ground segment of “Radioastron”, RT-22 of Crimean Astrophysical Observatory in Simeiz and RT-70 (P-2500) in Evpatoria jointly conducted groundbased VLBI test experiments at 1.35 cm [2].

2.3 Wavelet Analysis of Ground and

Satellite Measurements of Local

Insolation

[3] presented the possibility of using wavelet analysis on the signals from long sequences of local terrestrial and NASA satellite observations of the insolation

of the Center of HydroMeteorology (CHM) “Nikita

Garden” (latitude 44.5, longitude 34.2 degrees). The

choice of the method, the type of wavelets, and their

parameters for analysis were found. Then the wavelet

analysis was applied to the signals to determine and

remove the noise and to establish the spectral composition of the signal data. The local terrestrial signal measurements and data from the signals of the satellite observations were presented in [3], along with the noise

found from the statistical analysis of the observations.

3 Future Plans

Our plans for the coming year are the following: to

put into operation the VLBI Data Acquisition System

DBBC, to upgrade the laser of the SLR Simeiz-1873

station, and to set up a new GPS station near the Simeiz

VLBI station.

References

1. Volvach L.N., Berezhnoi A.A., Volvach A.E. Bulletin of

the Crimean Astrophysical Observatory, 109 (1), pp.71-75,

2012.

2. Volvach A.E., Kostenko V.I., Larionov M.G., Volvach L.N.,

et al. Bulletin of the Crimean Astrophysical Observatory,

108 (1), pp.158-162, 2012.

3. Kurbasova G.S., Volvach A.E. Bulletin of the Crimean Astrophysical Observatory, in press, 2014.

IVS 2013 Annual Report
162 Volvach and Kurbasova

Table 1 The antenna parameters of the Simeiz station.

Diameter D, m 22

Surface tolerance, mm (root mean square) 0.25

Wavelength limit, mm 2

Feed System Cassegrain system or primary focus

Focal length F, m 9.525

Focal ratio F/D 0.43

Effective focal length for Cassegrain system, m 134.5

Mounting Azimuth-Elevation

Pointing accuracy, arc sec. 10

Maximum rotation rate, degree/sec 1.5

Maximum tracking rate, arcsec/sec 150

Working range in Azimuth, degrees (0 to South) -270 ± 270

Degrees in Elevation 0 - 85

KATS-PIL

KATS-SLR

RT

22

SIMI-SLR

GPS-CRAO

Fig. 1 The Simeiz geodynamics area.

1,E+29

1,E+30

1,E+31

1,E+32

0,4 0,45 0,5 0,55 0,6 0,65

Q(OH), mol s-1

r, AU

Fig. 2 The relationship between the gas productivity of comet C/2009 R1 (McNaught) and the heliocentric distance.

IVS 2013 Annual Report
Simeiz VLBI Station 163

Kara Dag +

Perecop

+

Sarich

+

+

Fonar

+

Kara Mrun

+ Simferopol

(φ=46.2°, λ=33.7°)

(φ=45.4°, λ=36.6°)

(φ=45.4°, λ=32.7°)

(φ=44.96°, λ=34.11°, H=255 м)

(φ=44.93°, λ=35.22°, H=577 м)

(φ=44.4°, λ=33.7°)

Fig. 3 Crimean area.

1983.5 1986.2 1989 1991.7 1994.4 1997.2 1999.2 200 2.7 200 5.4 2008.1

3.4

3.5

3.6

3.7

3.8

3.9

4

4.1

4.2

4.3

4.4

Dat a

Av era ge Insolation Incident On A Horiz ontal Surfac e (tendency) 

swv kWh/m

2/day

K ara Dag

S imferop ol

P erekop (N )

S arich (S )

F onar ( E)

K ara Mr un (W )

K ara Dag

S

W

Simfero pol E

N

NAS A S urface m eteoro logy an d So lar Energy: Daily Averaged Data

Fig. 4 The insolation for the Crimean area.

IVS 2013 Annual Report
Svetloe Radio Astronomical Observatory 2013 IVS Annual Report

Sergey Smolentsev, Ismail Rahimov

Abstract This report provides information about the

Svetloe Radio Astronomical Observatory during 2013.

The report also provides an overview of current geodetic VLBI activities and gives an outlook for the next

year.

1 General Information

Svetloe Radio Astronomical Observatory (Figure 1)

was founded by the Institute of Applied Astronomy

(IAA) as the first station of the Russian VLBI network

QUASAR. The sponsoring organization of the project

is the Russian Academy of Sciences (RAS). The

Svetloe Radio Astronomical Observatory is situated

near Svetloe village in the Priozersky district of the

Leningrad region (Table 1). The geographic location

of the observatory is shown on the IAA RAS Web site:

http://www.ipa.nw.ru/PAGE/rusipa.htm. The basic instruments of the observatory are a 32-m radio telescope

equipped with special technical systems for VLBI

observations, GPS/GLONASS/Galileo receivers, the

SLR system, and a Water Vapor Radiometer (WVR).

Table 1 Svetloe Observatory location and address.

Longitude 29◦47′

Latitude 60◦32′

Leningrad region, Priozerski district

188833 Russia

rahimov@osvtl.spb.ru

Institute of Applied Astronomy of RAS

Network Station Svetloe

IVS 2013 Annual Report

Fig. 1 Svetloe observatory.

2 Technical Staff

Table 2 Staff related to VLBI operations at Svetloe.

Prof. Ismail Rahimov observatory chief

Vladimir Tarasov chief engineer

Tatiana Andreeva engineer

Andrey Mikhailov FS, pointing system control

164
Svetloe IVS Annual Report 165

3 Component Description

3.1 Technical and Scientific Information

Characteristics of the radio telescope are presented in

Table 3.

Table 3 Technical parameters of the radio telescope.

Year of construction 2000

Mount AZEL

Azimuth range ±270◦(from south)

Elevation range from −5

◦

to 95◦

Maximum azimuth

- velocity 0.83 ◦/s

- tracking velocity 2.5

′

/s

- acceleration 12.0

′

/s

2

Maximum elevation

- velocity 0.5

◦

/s

- tracking velocity 0.8

′

/s

- acceleration 12.0

′

/s

2

Pointing accuracy better than 10′′

Configuration Cassegrain (with

asymmetrical subreflector)

Main reflector diameter 32 m

Subreflector diameter 4 m

Focal length 11.4 m

Main reflector shape quasi-paraboloid

Subreflector shape quasi-hyperboloid

Main reflector surface accuracy ± 0.5 mm

Frequency range 1.4–22 GHz

Axis offset 3.7±2.0 mm

3.2 Co-location of VLBI, GPS/GLONASS,

SLR System, and WVR

The Topcon GPS/GLONASS/Galileo receiver with

meteo station WXT-510 is in operation (Figure 2).

The SLR system “Sazhen-TM” (Figure 3) was

mounted in October 2011 and joined the ILRS in

March 2012. The SLR system at Svetloe observatory

observed 353 passes of LAGEOS, GLONASS, and

others and obtained 3,040 normal dots during 2013.

Fig. 2 Topcon GPS/GLONASS/Galileo receiver at the Svetloe

observatory.

Fig. 3 “Sazhen-TM” SLR system at Svetloe observatory.

Fig. 4 WVR and RT-32 at Svetloe observatory.

IVS 2013 Annual Report
166 Smolentsev and Rahimov

4 Current Status and Activities during

2013

Svetloe observatory participates in IVS and domestic

VLBI observational programs. During 2013, Svetloe

station participated in 29 diurnal IVS sessions — 24

IVS-R4 sessions, one IVS-T2 session, four EURO sessions – and in 36 IVS-Intensive sessions.

Svetloe participated in 48 diurnal sessions in the

frame of the domestic Ru-E program for determination

of all Earth orientation parameters and in 20 one-hour

Ru-U sessions for obtaining Universal Time using eVLBI data transfer. Since April 2013, we have used

e-VLBI data transfer for Svetloe observational data for

the Ru-E 24-hour sessions.

In 2013, the WVR was installed and is successfully

working (Figure 5).

Fig. 5 WVR at Svetloe observatory.

5 Future Plans

Our plans for the coming year are the following:

• To participate in IVS observations,

• To carry out domestic observational programs for

obtaining Universal Time daily and for obtaining

Earth orientation parameters weekly with e-VLBI

data transfer,

• To carry out SLR observations of geodetic and navigation satellites,

• To participate in EVN and RADIOASTRON observational sessions,

• To continue geodetic monitoring of the RT-32 parameters, and

• To continue WVR observations.

IVS 2013 Annual Report
JARE Syowa Station 11-m Antenna, Antarctica

Yuichi Aoyama, Koichiro Doi, Kazuo Shibuya

Abstract In 2013, the 53rd, the 54th, and the 55th

Japanese Antarctic Research Expeditions (hereinafter,

referred to as JARE–53, JARE–54, and JARE–55,

respectively) participated in six OHIG sessions —

OHIG82, 83, 84, 85, 86, and 87. These data were

recorded on hard disks through the K5 terminal. The

hard disks for the OHIG82 session were brought

back from Syowa Station to Japan in April 2013 by

the icebreaker Shirase while those for the other five

sessions are scheduled to arrive in April 2014. The data

obtained from the OHIG79, 80, 81, and 82 sessions

by JARE–53 and JARE–54 were transferred to the

Bonn Correlator via the servers of National Institute

of Information and Communications Technology

(NICT). At Syowa Station, JARE–55 will participate

in six OHIG sessions in 2014.

1 General Information

To investigate polar science, the National Institute of

Polar Research (NIPR) is managing Japanese Antarctic Research Expeditions (JAREs). The 30 members of

JARE–54 overwintered at Syowa Station, East Ongul

Island, East Antarctica in 2013.

Syowa Station has become one of the key observation sites in the Southern Hemisphere’s geodetic and

geophysical networks (as shown in Figure 1, see [1]

for details). As a part of these geodetic measurements,

the JAREs have been operating the 11-m S/X–band anNational Institute of Polar Research

JARE Syowa Station 11-m antenna

IVS 2013 Annual Report

tenna at Syowa Station (69.0◦S, 39.6◦E) for geodetic

VLBI experiments since February 1998. A cumulative

total of 108 quasi-regular geodetic VLBI experiments

were performed by the end of 2013.

2 Component Description

For VLBI, the Syowa antenna is registered as IERS

Domes Number 66006S004 and as CDP Number 7342.

The basic configuration of the Syowa VLBI frontend

system has not changed from the description in [2].

Syowa’s K4 recording terminal was fully replaced by

K5 simultaneously with the termination of the SYW

session at the end of 2004. Syowa has participated in

the OHIG sessions in the austral summer season since

Fig. 1 Syowa VLBI antenna.

167
168 Aoyama et al.

Table 1 Staff members.

Name Affiliation Function Notes

Kazuo SHIBUYA NIPR Project coordinator until March 2013

Koichiro DOI NIPR Project coordinator since April 2013

Yuichi AOYAMA NIPR Liaison officer

Hideaki HAYAKAWA NIPR Chief operator of JARE–53

Takeshi YOSHIOKA NEC Antenna engineer for JARE–53

Noriaki OBARA NIPR Chief operator of JARE–54

Hiroshi TANAKA NEC Antenna engineer for JARE–54

Takuya MASUNAGA NIPR Chief operator of JARE–55 from Nov. 2013 to Jan. 2015

JARE–53: February 2012 – January 2013 JARE–54: February 2013 – January 2014

1999. Data transfer through an Intelsat satellite link

from Syowa Station to NIPR has been available since

2004. However, its recent bandwidth has been about

2 MB and its effective speed of FTP transfer has been

about 100kB/sec, which is too slow to practically transfer the huge VLBI data.

3 Staff of the JARE Syowa Station 11-m

Antenna

The Syowa Station 11–m antenna is operated and

maintained by JARE and NIPR. The staff members are

listed in Table 1. Prof. Shibuya retired on March 31,

2013, so K. Doi took over as the project coordinator of

our institute. OHIG sessions in 2013 were performed

primarily by the staff of JARE–54 as shown in Figure 2. The staff of JARE–53 supported them in the

OHIG82 session, in order to hand over the operation

and maintenance of the 11–m antenna to them. T.

Masunaga, a member of an advance team of JARE–55,

came to Syowa Station on November 15 by airplane.

Consequently, he could join the OHIG87 session as

their successor.

4 Current Status and Activities

4.1 Notes on System Maintenance

There used to be two hydrogen masers, Anritsu

RH401A HM–1001C, and HM–1002C at Syowa

Station. However, HM–1002C was brought back to

Japan in January 2011 for an overhaul. We attempted

Fig. 2 Syowa VLBI staff of JARE–54, N. Obara (left) and H.

Tanaka (right).

to return HM–1002C to Syowa Station immediately.

But it was impossible to transport it, because the

icebreaker Shirase could not approach Syowa Station

in the 2011/2012 and 2012/2013 austral summer

seasons due to dense and thick sea ice. Because it

was expected that it would be difficult for Shirase

to approach Syowa Station in the 2013/2014 austral

summer season, we decided to maintain HM1002C

at Anritsu Co., Ltd. without transporting it to Syowa

Station.

The other hydrogen maser, HM–1001C, has operated for VLBI observations since January 2011. On

March 11, 2011, trouble occurred in its ion pump and

in an uninterruptible power supply (UPS) for HM–

1002C because of instability in both voltage and frequency of the generator for power supplies at Syowa

Station. In January 2013, the UPS was repaired by replacing sealed batteries and the failed charging circuit.

IVS 2013 Annual Report
JARE Syowa Station 169

Table 2 Status of OHIG sessions as of December 2013.

Code Date Station Hour Correlation Solution Notes

OHIG76 2012/Feb/15 Sy, Ft, Hh, Kk, Oh, Tc 24 h Yes Yes J53

OHIG77 2012/Feb/28 Ft, Kk, Oh, Tc -Sy 24 h – – †1

OHIG78 2012/Feb/29 Ft, Hh, Kk, Oh, Tc -Sy 24 h No No †2

OHIG79 2012/Nov/06 Sy, Hb, Kk 24 h Yes Yes

OHIG80 2012/Nov/07 Sy, Ft, Hb, Kk, Tc 24 h Yes Yes

OHIG81 2012/Nov/14 Sy, Hb, Hh, Kk, Tc 24 h Yes Yes

OHIG82 2013/Feb/11 Sy, Hh, Kk, Oh, Tc 24 h Yes Yes J54

OHIG83 2013/Feb/13 Sy, Hh, Kk, Oh, Tc 24 h – –

OHIG84 2013/Feb/20 Sy, Ft, Kk, Oh, Tc 24 h – –

OHIG85 2013/Nov/11 Sy, Ft, Hb, Ke, Kk, Tc, Ww, Yg 24 h – –

OHIG86 2013/Nov/13 Sy, Ft, Hb, Ke, Kk, Tc, Ww, Yg 24 h – –

OHIG87 2013/Nov/20 Sy, Ft, Hb, Hh, Ke, Kk, Tc, Ww, Yg 24 h – –

J53: JARE–53, op H. Hayakawa eng T. Yoshioka J54: JARE–54, op N. Obara eng H. Tanaka

†1 : Canceled because of malfunction of HM–1001C.

†2 : No fringes because of malfunction of HM–1001C.

On the other hand, the ion pump began to abnormally stop on occasion since March 11, 2011. In

2013, such abnormal stops, which caused a low vacuum inside the HM–1001C and attenuated the hydrogen maser oscillator, occurred on January 6, May 8,

July 5, September 11, November 5, November 21,

and November 26. The JARE–54 staff had to form

high vacuum and check the hydrogen maser generation at all such times. Especially, abnormal stops occurred on November 21 during the OHIG87 session.

The ion pump stopped suddenly at 00:00 UTC just before the 36th scan, and the staff could not restart the

ion pump until 00:12 UTC. The IF level of the hydrogen maser was recovered and synchronized with GPS

around 01:55 UTC before the 45th scan. There may

be about two hours of unavailable data in the OHIG87

recorded data.

To avoid such critical situations, we purchased a

new hydrogen maser, SD1T03B, last year. SD1T03B

was miniaturized in order to be loaded on a helicopter.

Therefore, we could transport it to Syowa Station on

December 16. SD1T03B was connected to UPS for

HM1002C, and its startup was accomplished on December 20.

In preparing the OHIG82 session, the power modules of units 1 and 2 of K5 were broken. The malfunctioning modules were replaced with spare parts, so

that there was no apparent influence on the subsequent

OHIG sessions.

A system for Delay calibration (D–Cal) recording

is independent of the K5 system. D–Cal signals used

to be recorded at start/end of each Syowa scan onto

floppy disk (FD) by using an N88 BASIC program on

an ancient NEC PC. Although its FD drive broke down

in November 2012, it was replaced by a spare in January 2013, and D–Cal signals resumed being stored on

FD. The D–Cal recording program hung-up twice (45th

and 85th scans) during the OHIG85 session. As a consequence, the D–Cal signal data from scans 1 to 44 was

broken.

In the direction of north in the field of view of the

antenna, a few interference waves in S band were detected in the output signal of the video converter with

a spectrum analyzer. The obvious peaks appeared in

the frequencies of 212.1 MHz and 260.0 MHz in the

intermediate frequency of S band. We continue to investigate their source.

4.2 Session Status

Table 2 summarizes the status of processing as of

December 2013 for the sessions starting in 2012. The

OHIG sessions involved Fortaleza (Ft), O’Higgins

(Oh), Kokee Park (Kk), TIGO Concepcion (Tc), Ho-  ́

bart 12-m antenna (Hb), HartRAO (Hh), Warkworth

(Ww), Katherine (Ke), Yarragadee (Yb), and Syowa

(Sy). In 2005, Syowa joined the CRD sessions, but

after 2006, Syowa participated only in OHIG sessions.

Syowa took part in six OHIG sessions in 2013.

K5 HDD data brought back from Syowa Station

were transferred to NICT servers and converted to the

IVS 2013 Annual Report
170 Aoyama et al.

Mark 5 format data there. The converted data were

transferred from the NICT servers to the Bonn Correlator by FTP.

4.3 Analysis Results

As of December 2013, Syowa had contributed 97 sessions from May 1999. According to the results analyzed by the BKG IVS Analysis Center, the length of

the Syowa–Hobart baseline is increasing with a rate

of 52.6 ± 0.9 mm/yr. The Syowa–HartRAO baseline

shows a slight increase in its length with a rate of

13.1 ± 0.6 mm/yr. The Syowa–O’Higgins baseline also

shows a slight increase, although its rate is only 3.0 ±

1.1 mm/yr. Detailed results from the data until the end

of 2003 as well as comparisons with those from other

space geodetic techniques were reported in [3].

5 Future Plans

Dismantling the current Syowa VLBI antenna is scheduled for the 2015/2016 austral summer season. We presented a budget proposal for construction of a new

VGOS antenna after 2017. We will make every effort

until this proposal is approved. Simultaneously, we are

preparing to install a small geodetic VLBI antenna in

collaboration with NICT. We would like to shorten the

discontinuation period of VLBI observations as much

as possible.

References

1. Shibuya, K., Doi, K., and Aoki, S. (2003): Ten years’

progress of Syowa Station, Antarctica, as a global geodesy

network site. Polar Geoscience, 16, 29-52.

2. Shibuya, K., Doi, K., and Aoki, S. (2002): JARE Syowa Station 11-m Antenna, Antarctica, in International VLBI Service for Geodesy and Astrometry 2002 Annual Report, 149-

152, NASA/TP-2003-211619, ed. by N. R. Vandenberg and

K. D. Baver.

3. Fukuzaki, Y., Shibuya, K. Doi, K., Ozawa, T., Nothnagel,

A., Jike, T., Iwano, S., Jauncey, D.L., Nicolson, G.D., and

McCulloch, P.M. (2005): Results of the VLBI experiments

conducted with Syowa Station, Antarctica. J. Geod., 79,

379-388.

IVS 2013 Annual Report
Status of the TIGO VLBI Station in Concepcion ́

Hayo Hase 1, Cristian Herrera 2, Pedro Pino 2, Cristian Beltran 2

Abstract The main activities at the TIGO VLBI station during 2013 were observing 117 scheduled VLBI

sessions and progressing with the future cooperation

with Argentina for the new site near La Plata. The

acronym TIGO will be replaced by AGGO, once the

Tigo radio telescope is installed in Argentina.

1 General Information

Since 2002, TIGO has been located in the terrain of the

Universidad de Concepcion (longitude 73.025 degrees  ́

West, latitude 36.843 degrees South), in Concepcion,  ́

Chile.

2 Component Description

The IVS network station TIGOCONC constitutes the

VLBI part of the Geodetic Observatory TIGO, which

was designed to be a fundamental station for geodesy.

Hence, the VLBI radio telescope is co-located with an

SLR telescope (ILRS site), a GPS/Glonass permanent

receiver (IGS site), and other instruments such as a

seismometer, a superconducting gravimeter, and an absolute gravity meter.

The atomic clock ensemble of TIGO consists of

three hydrogen masers, three cesium clocks and four

1. Bundesamt fur Kartographie und Geod  ̈ asie  ̈

2. Universidad de Concepcion ́

TIGOCONC Network Station

IVS 2013 Annual Report

Fig. 1 The TIGO radio telescope.

GPS time receivers realizing the Chilean contribution

to the Universal Time scale (Circular T, BIPM).

The technical parameters of the TIGO radio telescope as published in [1] have not been changed.

3 Staff

The 2012 VLBI staff consisted of three persons, as

listed in Table 1. Pedro Pino left TIGO in September and was replaced by Cristian Beltran. The team

was complemented by students Pablo Figueroa and Dr.

Sabina Rayo performing night shifts.

171
172 Hase et al.

Table 1 TIGO VLBI support staff in 2013.

Staff Function Email Remark

Hayo Hase Head hayo.hase@tigo.cl

Cristian Herrera Informatic Engineer cristian.herrera@tigo.cl

Pedro Pino Electronic Engineer pedro.pino@tigo.cl until September 2013

Cristian Beltran Electronic Engineer cristian.beltran@tigo.cl until end of 2013

Sabina Rayo student of mechanical engineering sabina.rayo@tigo.cl

Pablo Figueroa student of telecommunications pablo.figueroa@tigo.cl

all VLBI operators vlbistaff@tigo.cl

4 Current Status and Activities

4.1 IVS Operation

During 2013, TIGO was scheduled to participate in

114 regular IVS experiments. Three 24-hour additional

participations were carried out within the TANAMI

project [2]. Table 2 gives an overview about the participation of TIGOCONC in 2013. Out of 117 requested

observation days, 113 could be observed successfully,

reaching an efficiency of 96.5%. The main reasons for

data loss have been related to technical problems in

the refrigerating system of the receiver, recording problems on bad data carriers, and unexpected delays in the

customs liberation procedure of data carriers.

Table 2 TIGO’s observation statistics for 2013.

Name R1xxx R4xxx OHIGxx T2 RD TANAMI Total

# of Exp. 51 50 6 4 3 3 117

Correlated 49 48 6 4 3 3 113

No result 2 2 0 0 0 0 4

4.2 Search for New Site for TIGO

The TIGO project is carried out on the basis of governmental decree 489. During the past few years the

Chilean government did not respond to the call to support this bilateral cooperation project. For this reason the German Federal Agency of Cartography and

Geodesy (BKG) looked for a new project partner in

South America, and an agreement with the Argentinean science foundation Conicet was signed in October 2013. In the year 2014, the TIGO project will be

closed in Chile and moved to the vicinity of the town of

La Plata. The project will then be called Argentinean

German Geodetic Observatory (AGGO).

The future site was decided to be 500 m away from

the existing Instituto Argentino de Radioastronomia

(IAR). AGGO will be dependent on Conicet but independent from IAR. BKG and Conicet have laid out

a development plan. In phase 1 AGGO will make use

of TIGO as it was operated in Concepcion. In phase 2  ́

the installations within the containers will be moved to

an operations building, so that containers older than 20

years can be abandoned.

5 Future Plans

The VLBI activities in 2014 will be focused on:

• execution of the IVS observation program for 2014,

• photogrammetric reflector survey, and

• overhaul and preparing the VLBI equipment for the

move to Argentina.

References

1. Vandenberg, N.R.: International VLBI Service for Geodesy

and Astrometry 1999 Annual Report, NASA/TP–1999-

209243, 1999.

2. M. Kadler, R. Ojha, S. Tingay and J. Lovell, The TANAMI

Program: Southern-Hemisphere VLBI Monitoring of Relativistic Jets in Active Galaxies, American Astronomical Society, AAS Meeting #211, #04.13; Bulletin of the American

Astronomical Society, Vol. 39, p.732.

IVS 2013 Annual Report
Tsukuba 32-m VLBI Station

Takahiro Wakasugi1, Ryoji Kawabata1, Shinobu Kurihara1, Yoshihiro Fukuzaki1, Jiro Kuroda1, Tadashi Tanabe1,

Syota Mizuno1,2, Takafumi Ishida1,2

Abstract The Tsukuba 32-m VLBI station is operated by the Geospatial Information Authority of Japan.

This report summarizes activities of the Tsukuba 32-m

VLBI station in 2013. 115 sessions were observed by

using Tsukuba 32-m and other GSI antennas in accordance with the IVS Master Schedule of 2013 except

for the interruption period due to the repair of the antenna base of Tsukuba 32-m. We have been constructing the new observing facilities that will be fully compliant with VGOS for the first time in Japan.

Fig. 1 Tsukuba 32-m VLBI station.

1. Geospatial Information Authority of Japan

2. Advanced Engineering Service Co., Ltd.

Tsukuba Network Station

IVS 2013 Annual Report

1 General Information

The Tsukuba 32-m VLBI station (Figure 1) is located

at the Geospatial Information Authority of Japan (hereafter GSI) in Tsukuba science city, which is about 50

km to the northeast of Tokyo. GSI has three regional

stations besides Tsukuba: Shintotsukawa, Chichijima,

and Aira, which form a geodetic VLBI network in

Japan covering the whole country (Figure 2).

GSI has carried out the domestic VLBI session series called “JADE (JApanese Dynamic Earth observation by VLBI)” since 1996. The main purposes of the

JADE series are to maintain the reference frame of

120 ̊

120 ̊

130 ̊

130 ̊

140 ̊

140 ̊

150 ̊

150 ̊

20 ̊ 20 ̊

30 ̊

30 ̊

40 ̊

40 ̊

50 ̊

50 ̊

Chichijima

Tsukuba

Ishigakijima(NAOJ)

Mizusawa(NAOJ)

Aira

Shintotsukawa

Fig. 2 Geodetic VLBI network in Japan.

173
174 Wakasugi et al.

Japan and to monitor plate motions for the advanced

study of crustal deformation around Japan. Additionally, some JADE sessions include Mizusawa and Ishigakijima, which are part of the VERA network of the

National Astronomical Observatory of Japan (NAOJ),

and two antennas in Kashima (11-m and 34-m) and the

Koganei 11-m station, which belong to the National Institute of Information and Communications Technology (NICT).

2 Component Description

The specifications of the Tsukuba 32-m antenna are

summarized in Table 1.

Table 1 Tsukuba 32-m antenna specifications.

Owner and operating agency Geospatial Information

Authority of Japan

Year of construction 1998

Radio telescope mount type Az-El

Antenna optics Cassegrain

Diameter of main reflector 32 m

Azimuth range 10 – 710◦

Elevation range 5 – 88◦

Az/El drive velocity 3

◦

/sec

Tsys at zenith (X/S) 50 K / 65 K

SEFD (X/S) 320 Jy / 360 Jy

RF range (X1) 7780 – 8280 MHz

RF range (X2) 8180 – 8680 MHz

RF range (X3) 8580 – 8980 MHz

RF range (S with BPF) 2215 – 2369 MHz

Recording terminal K5/VSSP32,

ADS3000+ with DDC

3 Staff

Table 2 lists the regular members belonging to the

GSI VLBI observation group. Takahiro Wakasugi

newly joined in our group and was in charge of station

operation mainly. Routine operations were primarily

performed under contract with Advanced Engineering

Service Co., Ltd. (AES). Syota Mizuno and Takafumi

Ishida replaced Yasuko Mukai and Takashi Nishikawa

as new operators since November.

Table 2 Member list of the GSI VLBI group.

Name Main Function

Tadashi TANABE Supervisor

Jiro KURODA Management, Co-location

Yoshihiro FUKUZAKI Installation of VGOS

Shinobu KURIHARA Correlation, Analysis,

IVS Directing Board member

Ryoji KAWABATA Operation, Co-location

Takahiro WAKASUGI Operation

Kazuhiro TAKASHIMA Research

Syota MIZUNO Operation(AES, Co., Ltd)

Takafumi ISHIDA Operation(AES, Co., Ltd)

Toshio NAKAJIMA System engineer(I-JUSE)

4 Current Status

4.1 Geodetic VLBI Observations

The regular sessions in the IVS Master Schedule that

were observed by using the GSI antennas are shown

in Table 3. The Tsukuba 32 m participated in 39

domestic and international 24-hr VLBI sessions and in

56 Intensive 1-hr sessions for dUT1 measurement in

2013. The Tsukuba 32 m could not participate in the

IVS sessions from the beginning of May to the end of

November due to the repair of the antenna base (see

Section 4.2). The other GSI antennas, Shintotsukawa,

Chichijima, and Aira participated in not only domestic

but also some international sessions.

Table 3 The number of regular sessions carried out by using the

GSI antennas in 2013.

Sessions Tsukuba Shintotsukawa Chichijima Aira

IVS-R1 21 – – 10

IVS-R4 5 – – –

IVS-T2 3 – 7 7

APSG 1 2 2 2

VLBA 3 – – –

IVS-R&D 3 – – –

IVS-CRF 0 – – –

JADE 3 7 9 9

IVS-INT1 7 – – –

IVS-INT2 34 – – –

IVS-INT3 15 – – –

Total 95 9 18 28

IVS 2013 Annual Report
Tsukuba 32-m VLBI Station 175

4.2 Repair of the Tsukuba 32-m Antenna

At the end of April, we found that the damage of the

antenna base was very serious from the results of a

pointing check with X-band and decided to interrupt all

experiments after early May. We investigated the damage of the antenna immediately and found that there

were some gaps between the sole plates under the rail

tracks and cementitious grout, which could cause the

subsidence of the antenna (Figure 3). Then, we filled

all gaps with new firm grout in order to prevent the antenna from subsiding. After confirming that the result

of the pointing check was alright, we resumed IVS sessions with the Tsukuba 32 m from the end of November. Although we confirmed that the rail track level was

almost the same as before the repair, we will perform

field surveys in early 2014 in order to make sure the

reference point does not move.

We carried out R1 sessions 10 times by using Aira

from the end of September to the end of November on

behalf of the Tsukuba 32 m after modifying the down

converter to receive the R1 sessions’ frequency band.

These sessions were performed with a high-speed A/D

sampler ADS3000+ and K5/VSI system, which have

been developed by our collaborator NICT. We plan to

continue R1 sessions by using Aira until the end of

March 2014 in parallel with the Tsukuba 32 m.

5DLOWUDFN

6ROHSODWH

*URXW

Fig. 3 A gap under a sole plate detected after excavating grout.

4.3 VGOS Project by GSI

In 2012, we had started construction of the new GSI

VGOS observing facilities in Ishioka city located about

17 km northeast from Tsukuba (Figure 4). Some part

of the antenna and observing cabin were delivered to

the site by the end of 2013 and the construction of the

antenna will be completed by the end of March 2014

(Figure 5). The other equipment such as a front-end

feed, up-down converter, data processing and acquisition system and so on were already delivered to GSI.

We decided to call the new site iGOS (Ishioka Geodetic

Observing Station) that includes GNSS continuous observation system and gravity observing point in order

to play an important role of the geodetic site based on

GGOS (Global Geodetic Observing System) in Japan.

Tsukuba

iGOS

Koganei(NICT)

Kashima(NICT)

Tokyo

17km

Fig. 4 Location of iGOS site.

5 Future Plans

As mentioned above, the new VGOS station in Ishioka

will be installed by the end of March 2014. We will

carry out some tests and adjustments to obtain fringes

between the existing system and the new one. Subsequently, we plan to carry out parallel operation from

2015 to 2016. After these sessions, we plan to participate in VGOS sessions thoroughly from 2017.

On the other hand, we have to consider the deterioration of the regional stations. We decided to close

Shintotsukawa, which was installed in 1995, from the

IVS 2013 Annual Report
176 Wakasugi et al.

Fig. 5 Construction of the antenna.

beginning of 2014 because of aging. We will also continue to consider the other GSI stations.

IVS 2013 Annual Report
Nanshan VLBI Station Report 2013

Ming Zhang, Ali Yusup

Abstract Urumqi Nanshan station is a key node of

the Chinese VLBI Network (CVN). It participates

in global VLBI observations for the IVS, EVN, and

EAVN networks. This report provides an overview

of geodetic and astronomical activities and technical

development at XAO during 2013.

1 Introduction

Fig. 1 The 25-m antenna at Nanshan station.

The Nanshan VLBI station is located 70 km south of

Urumqi, the capital city of the Xinjiang Uyghur Autonomous Region of China. The station is affiliated

with the Xinjiang Astronomical Observatory of the National Astronomical Observatories of CAS. In 2013,

we have participated in geodetic observations for IVS

Xinjiang Astronomical Observatory, Chinese Academy of Sciences

Xinjiang Astronomical Observatory

IVS 2013 Annual Report

as well as in astronomical observations for EVN, CVN

and EAVN.

2 Current Status

2.1 Antenna

• Coordinates: Longitude: 87◦10′41′′ E; Latitude:

43◦28′17′′ N; Altitude: 2080 m

• Diameters: Primary: 25 m; Secondary: 7 m

• Antenna type: Modified Cassegrain

• Seat-rack type: Azimuth-pitching ring

• Main surface precision: 0.40 mm (rms)

• Pointing precision: 15′′ (rms)

• Turning angle: Azimuth: ±270◦; Elevation: 5◦-

88◦

• Slew speed: Azimuth: 0.9◦/sec; Elevation: 0.5◦/sec

2.2 Receivers

The receiver parameters of the 25-m antenna are shown

in Table 1.

2.3 Recording System

The recording systems available at the Nanshan VLBI

station are Mark 5B+, Mark IV, Mark II, and K5. The

Mark 5 StreamStor SDK has been upgraded from version 8.1 to 9.2. The Field System now is being upgraded from version 9.10.4 to 9.11.4. The analog BBC

177
178 Zhang and Yusup

Table 1 The receiver parameters of the 25-m antenna.

Band Wave Freq BW LO Pol

(cm) (MHz) (MHz) (MHz)

L 18 1400-1720 320 1300 dual

S 13 2150-2450 300 2000 dual

C 6 4750-5150 400 4620 dual

X 3.6 8200-9100 500 8100/8600 dual

K 1.3 22100-24200 500 22000-23700 dual

Band Type T rec T sys Eff SEFD

(K) (K) (%) (Jy)

L room 10 24 52 300

S room 50 70 48 560

C room 9 22 55 250

X cryo 20 50 50 350

K cryo 17 40 35 850

used here is old but still able to record at a maximum

rate of 2,048 Mbps with a maximum channel width

of 16 MHz and a maximum of 16 channels. The digital backend system we have here is a Chinese Data

Acquisition System (CDAS), which was developed by

Shanghai Astronomical Observatory.

3 IVS Observations

We have observed 12 scheduled IVS sessions in 2013.

All of them were observed normally.

Table 2 The observed IVS sessions.

Session Date Remarks

R4569 JAN 24 Normal

R4579 APR 04 Normal

APSG32 APR 17 Normal

R4582 APR 25 Normal

APSG33 MAY 20 Normal

R4595 JUL 25 Normal

R1604 SEP 24 Normal

R1612 NOV 18 Normal

T2093 NOV 19 Normal

R1613 NOV 25 Normal

R1617 DEC 23 Normal

R1618 DEC 30 Normal

4 Personnel

See Table 3 for Urumqi personnel.

5 Future Plans

A planned reconstruction of the 25-m antenna will take

place in March 2014 and will be completed in October

2014. A digital backend RDBE and a DBBC are both

in our purchase plan.

IVS 2013 Annual Report
Nanshan VLBI Station 179

Table 3 The staff supporting the 25-m antenna.

Name Position Field E-mail

Na Wang Director Astrophysics na.wang@xao.ac.cn

Ali Yusup Chief Engineer Antenna aliyu@xao.ac.cn

Maozheng Chen Senior Engineer Receiver mzchen@xao.ac.cn

Jun Ma Senior Engineer Receiver majun@xao.ac.cn

Wenjun Yang Senior Engineer Terminal yangwj@xao.ac.cn

Hua Zhang Senior Engineer Terminal zhangh@xao.ac.cn

Shiqiang Wang Senior Engineer Antenna wangshq@xao.ac.cn

Jun Nie Senior Engineer Computing niejun@xao.ac.cn

Guanghui Li Engineer Computing ligh@xao.ac.cn

Chenyu Chen Engineer Antenna chency@xao.ac.cn

Mingshuai Li Engineer Time and Frequency limingsh@xao.ac.cn

Xiang Liu Scientist Astrophysics liux@xao.ac.cn

Ming Zhang Scientist Astronomy zhang.ming@xao.ac.cn

IVS 2013 Annual Report
Warkworth Radio Astronomical Observatory, New Zealand

Hiroshi Takiguchi, Stuart Weston, Tim Natusch, Sergei Gulyaev

Abstract We describe geodetic research activities related to the Warkworth 12-m VLBI Station:

WARK12M. We present a summary of baseline lengths

(obtained with the participation of WARK12M) based

on IVS results for the 2.5 year period, from the beginning of 2011 to August 2013, and compare them with

baselines for the corresponding (co-located) GNSS

stations.

1 Introduction

New Zealand′s location on the boundary of the Pacific and Australian Plates makes it one of the most

active geological areas in the world [1]. Figure 1 shows

the plate boundary, epicenters of earthquakes in the

last 3.5 years and location of major volcanoes in New

Zealand. Two continuous GNSS networks are used in

New Zealand to monitor these geological processes:

PositioNZ and GeoNet [2]. The PositioNZ network of

31 GNSS stations has been used to support the New

Zealand Geodetic Datum 2000 (NZGD2000) [3]. Prior

to 2008, New Zealand had no VLBI capability; the

NZGD2000 was therefore based solely on GNSS data

and ITRF96. GeoNet is a network designed for monitoring earthquakes, volcanic activity, and crustal deformation. The New Zealand Velocity Model has been estimated by using GeoNet network data [4]. This model

is referenced to the Australian Plate, so points near

Auckland move little, points near Christchurch move

Institute for Radio Astronomy and Space Research, Auckland

University of Technology

Warkworth Network Station

IVS 2013 Annual Report

southwest at about 40 mm/yr. About 5 mm/yr uplift is

reported in the Southern Alps of the South Island from

GNSS observations [5].

The Global Geodetic Observing System (GGOS)

aims to achieve a challenging 1 mm positioning and

0.1 mm/yr velocity accuracy by using and integrating

advanced geodetic techniques [6], [7]. To achieve these

goals, geodetic (GGOS) stations should be equipped

with two or more co-located geodetic observation techniques (e.g., GNSS and VLBI).

New Zealand first obtained the space geodetic technique of VLBI in 2008 when Auckland University

of Technology (AUT) established a 12-m geodetic radio telescope near Warkworth, 60 km north of Auckland (Figure 1). In 2010, WARK12M became an IVS

network station. Within the scope of global geodetic VLBI observations, WARK12M plays an important

role in improving the geographic distribution of VLBI

stations in the Southern Hemisphere and contributing to the definition of both the International Celestial Reference Frame (ICRF) and the International Terrestrial Reference Frame (ITRF) [8]. Locally, within

the New Zealand context, WARK12M provides important geodetic information which can be used (in conjunction with GNSS data) to support the NZGD2000

and contribute to establishment of the next generation,

GGOS inspired, New Zealand Geodetic Datum.

In addition to participating in regular IVS sessions,

WARK12M is engaged in joint geodetic research with

the National Institute of Information and Communications Technology (NICT), Japan and with the AuScope

project [9]. The latter operates three 12-m radio telescopes located in Hobart (HOBART12), Yarragadee

(YARRA12M), and Katherine (KATH12M). Located

on the Australian tectonic plate, both WARK12M

and AuScope radio telescopes are ideally placed

180
Warkworth Observatory 181

for measurements of intra-plate deformation. The

WARK12M–AuScope baselines are long enough

to contribute to Earth Orientation Parameter (EOP)

observations, particularly when coupled together with

New Zealand–Japan (NICT) baselines (Figure 2).

2 Warkworth Developments

Specifications of Warkworth 12-m and 30-m antenna

are provided in Table 1 and Table 2.

During 2013, work continued on the 30-m

(Cassegrain beam-waveguide NEC antenna) dish

as first reported in [10]. In February 2013, the dish

became fully steerable with the commissioning of a

new control system and motors supplied by Control

Technologies and Antenna Measurement and Consultancy Services. In October and November 2013, with

the assistance of Ed Himwich, we commenced work

to develop a first pointing model using the existing

Satellite Communication C-Band RF system and a

new Field System. An uncooled C-band receiver is

currently under development; significant improvement

in performance is anticipated once it is fitted to the

antenna.

In 2014, the existing 1 Gbps network connection to

Warkworth will be upgraded to 10 Gbps, greatly enhancing our eTransfer throughput for IVS. Currently

eTransfers to the Curtin correlator (for example) are

limited to a maximum sustained rate of just over 800

Mbps with the existing 1 Gbps link via KAREN and

AARNET. The 15-day continuous AUST experiment

of December 2013 conducted with AuScope and HartRAO required some two weeks to eTransfer the approximately 100TBytes of data collected with the existing service.

3 Analysis of VLBI and GNSS Baselines

for Warkworth

Since 2012, AUT has been engaged in collaborative

research with NICT, which operates three IVS network

stations (KASHIM34, KASHIM11, KOGANEI).

Teams at both institutions have worked towards

establishing a “geodetic environment” — correlation

processing, bandwidth synthesis, VLBI data analysis,

Table 1 Specifications of the Warkworth 12-m antenna.

Antenna type Dual-shaped Cassegrain

Manufacturer Cobham/Patriot, USA

Main dish Diam. 12.1 m

Secondary refl. Diam. 1.8 m

Focal length 4.538 m

Surface accuracy 0.35 mm

Pointing accuracy 18′′

Mount alt-azimuth

Azimuth axis range 90◦ ±270◦

Elevation axis range 4.5

◦

to 88◦

Azimuth axis max speed 5◦/s

Elevation axis max speed 1◦/s

Table 2 Specifications of the Warkworth 30-m antenna.

Antenna type Cassegrain, beam waveguide

Manufacturer NEC, Japan

Main dish Diam. 30 m

Frequency range 3.5 — 7 GHz

Mount alt-azimuth, wheel and track

Azimuth axis range −179.0

◦

to 354.0

◦

Elevation axis range 6.0

◦

to 90.1

◦

Azimuth axis max speed 15.0

◦

/min

Elevation axis max speed 21.6

◦

/min

and Time and Frequency Transfer by using VLBI.

The baseline WARK12M–KASHIM11 is a long

North-South baseline of over 8000 km (Figure 2).

The first observation of the WARK12M–KASHIM11

baseline carried out in 2012 resulted in the baseline

length of 8,075,003,545±150 mm. More observations

for monitoring this baseline are in preparation, as well

as an experiment aimed to derive Earth Orientation

Parameters in an Ultra-rapid mode by using existing

UT1 products and high-speed data transfer networks.

Since 2011, AUT has also been engaged in collaborative research with the AuScope project. Here

we analyse Warkworth–AuScope baseline lengths and

their rates of change using IVS Analysis Center results. The number of sessions and session types (R1,

R4, AUSTRAL) are listed separately in Table 3.

We analyzed databases of the three types (R1, R4,

AUSTRAL) using Calc/Solve software. Different types

of IVS sessions are optimised for different purposes.

For example, R1 and R4 sessions are optimised for

providing twice-weekly EOP results; the purpose of

AUSTRAL sessions is to determine the station coordinates and their evolution in the WARK12M–AuScope

network. It is important, therefore, to apply a uniform

strategy across all session types when analyzing the

VLBI databases. When analyzing AUSTRAL sessions,

IVS 2013 Annual Report
182 Takiguchi et al.

we used only WARK12M and AuScope station data.

For R1 and R4 sessions, we excluded TIGOCONC

and Japanese stations (TSUKUM32, KASHIM34 and

KASHIM11) in order to avoid the effects of potential

earthquake after-slip.

Figure 3 shows the baseline length residuals vs.

time for three baselines that include Warkworth. The

linear trends of baselines estimated for different types

of sessions are provided in each graph in brackets along

with the standard errors. The rates of change determined from VLBI data and the corresponding standard

errors are of the same order of magnitude, so based on

this data we cannot as yet conclude that the above rates

of change are statistically significant.

WARK12M and AuScope VLBI stations are colocated with the corresponding GNSS stations WARK,

HOB2, KAT1, and YAR2 (Figure 2). We analyzed

GNSS data of the co-located IGS (and PositioNZ) stations using GAMIT/GLOBK software. We combined

the results with the SOPAC global network file.

Figure 4 shows the baseline length residuals and the

linear trends of three baselines between Warkworth and

AuScope co-located GNSS stations. Rates of change

indicated in Figure 4 were estimated by formally fitting linear functions to all sets of GNSS baseline data.

All GNSS rates of change are very small (about 1-2

mm/yr), which seems realistic given that all four stations are located on the same tectonic plate. Due to the

small number of observations, the errors of VLBI rates

are greater than the order of magnitude of the rates

themselves. There is a clear annual/seasonal periodic

pattern in GNSS baseline data (Figure 4) with an amplitude of about 5-10 mm. We do not have enough data

to identify an annual pattern in VLBI data that include

WARK12M.

4 Conclusion

Auckland University of Technology operates a 12-

m geodetic radio telescope in New Zealand and

participates in collaborative research programs in

space geodesy with IVS, NICT, and AuScope. We

have analyzed the first 2.5 years of IVS observations

in which WARK12M participated and compared

the Warkworth–AuScope baseline lengths and their

changes with the corresponding GNSS results. We

do not find long term (>1 year) changes in GNSS

baselines, but do find an annual periodic pattern with

an amplitude of 5-10 mm. The small number of VLBI

baseline measurements and large errors do not allow

robust conclusions about VLBI baseline changes with

certainty at this time.

To monitor tectonic dynamics with high precision,

a large number of observations is necessary. It is important to carry out observations continuously with minimal gaps. This was not the case in the first 2.5 years

of WARK12M geodetic VLBI observations. We hope

regular and more frequent observations will improve

the accuracy of WARK12M VLBI measurements in the

future.

Australian

Plate

Pacific

Plate

Fig. 1 New Zealand’s geological situation. Tectonic plate

boundary is shown with the white curve. Dots indicate the earthquake epicenter locations (M ≥ 1, from January 2010 to July

2013) according to the USGS/NEIC earthquake catalog. Triangles indicate locations of major volcanoes. The location of

WARK12M is marked with a star.

Table 3 The number of sessions used for calculations over the

total number of sessions of a given type.

WARK12M WARK12M WARK12M

HOBART12 KATH12M YARRA12M

ALL 15/23 10/12 7/8

R1 4/6 5/6 2/2

R4 6/7 2/2 3/3

AUSTRAL 4/4 3/3 2/3

Others 1/6 0/1 0/0

IVS 2013 Annual Report
Warkworth Observatory 183

8075 km

2416 km

4753 km

5362 km

HOB2 

KAT1 

YAR2 

WARK 

KASHIM11

HOBART12

KATH12M 

YARRA12M

WARK12M 

Fig. 2 The geographical distribution of VLBI stations

(WARK12M, AuScope, KASHIM11) with baseline lengths.

−40

−20

 0

 20

 40

2011/01 2011/07 2012/01 2012/07 2013/01 2013/07

mm

WARK12M − HOBART12 (−3.30 ± 1.31 mm/yr)

−40

−20

 0

 20

 40

2011/01 2011/07 2012/01 2012/07 2013/01 2013/07

mm

WARK12M − KATH12M ( 6.73 ± 5.46 mm/yr)

−40

−20

 0

 20

 40

2011/01 2011/07 2012/01 2012/07 2013/01 2013/07

mm

WARK12M − YARRA12M ( 3.28 ± 3.55 mm/yr)

Fig. 3 Time series of the baseline length residuals of WARK12M

and AuScope baselines. Points and squares indicate R1 and

R4 session respectively. Asterisks indicate AUSTRAL session.

Rates of change (linear trends) and standard errors are shown in

brackets.

−40

−20

 0

 20

 40

2011/01 2011/07 2012/01 2012/07 2013/01 2013/07

mm

WARK − HOB2 (−2.40 ± 0.34 mm/yr)

−40

−20

 0

 20

 40

2011/01 2011/07 2012/01 2012/07 2013/01 2013/07

mm

WARK − KAT1 (−0.81 ± 0.46 mm/yr)

−40

−20

 0

 20

 40

2011/01 2011/07 2012/01 2012/07 2013/01 2013/07

mm

WARK − YAR2 (−1.64 ± 0.44 mm/yr)

Fig. 4 Time series of the baseline length residuals calculated

from GNSS data (WARK, HOB2, KAT1, YAR2). Rates of

change (linear trends) and standard errors are shown in brackets.

Acknowledgements

The authors would like to acknowledge organisations

and institutions such as IVS, IGS, LINZ, GNS Science, NICT, Geoscience Australia, University of Tasmania and CSIRO. We are grateful to the makers of

Calc/Solve, GAMIT/GLOBK, and Generic Mapping

Tools developers for providing the software.

References

1. Rafferty, John P. (2010), Plate tectonics, volcanoes, and

earthquakes, p312.

2. Beavan, R. J. (2005), Noise properties of continuous GPS

data from concrete pillar geodetic monuments in New

Zealand, and comparison with data from US deep drilled

braced monuments. Journal of geophysical research. Solid

earth, 110(B8): B08410, doi:10.1029/2005JB003642.

3. Pearse, M. (2000), Realisation of the New Zealand Geodetic

Datum 2000, OSG Technical Report, 5.

4. GNS Science, http://www.gns.cri.nz/Home/Our-Science

/Earth-Science/Plate-Tectonics/Deformation-of-NZ.

5. Beavan, J., et al. (2010), Distribution of present-day vertical deformation across the Southern Alps, New Zealand,

from 10 years of GPS data, Geophysical research letters, 37:

L16305, doi:10.1029/2010GL044165.

6. H.-P. Plag, M. Pearlman (eds.) (2009), Global Geodetic Observing System, DOI 10.1007/978-3-642-02687-4 1.

7. GGOS Vision, Mission and Goals. (2011). Officially

adopted by the Global Geodetic Observing System Steering Committee at its 21st Meeting on July 2, 2011 at

the IUGG XXV General Assembly, Melbourne, Australia.

http://www.ggos.org/

8. Takiguchi, H., S. Gulyaev, T. Natusch, S. Weston, and

L. Woodburn (2011), Towards Synergy of VLBI and

GNSS Geodetic Techniques in Geologically Dynamic New

Zealand, Advances in Geosciences, Vol. 31, 33-42.

9. Lovell, J.E.J., McCallum, J.N., Reid, P.B., McCulloch, P.M.,

Baynes, B.E., Dickey, J.M., Shabala, S.S., Watson, C.S.,

Titov, O., Ruddick, R., Twilley, R., Reynolds, C., Tingay,

S.J., Shield, P., Adada, R., Ellingsen, S.P., Morgan, J.S. and

Bignall, H.E. (2013), The AuScope geodetic VLBI array,

Journal of Geodesy, 87, 6, 527-538, doi:10.1007/s00190-

013-0626-3.

10. Weston, S., H. Takiguchi, T. Natusch, L. Woodburn,

S. Gulyaev (2013), Warkworth 12-m VLBI Station:

WARK12M, IVS 2012 Annual Report, NASA/TP-2013-

217511.

IVS 2013 Annual Report
Westford Antenna 2013 Annual Report

Mike Poirier

Abstract Technical information is provided about the

antenna and VLBI equipment at the Westford site of

the Haystack Observatory and about changes to the

systems since the IVS 2012 Annual Report.

1 Westford Antenna at Haystack

Observatory

Since 1981, the Westford antenna has been one of the

primary geodetic VLBI sites in the world. Located ∼70

km northwest of Boston, Massachusetts, the antenna is

part of the MIT Haystack Observatory complex.

The Westford antenna was constructed in 1961 as

part of the Lincoln Laboratory Project West Ford that

demonstrated the feasibility of long-distance communication by bouncing radio signals off a spacecraftdeployed belt of copper dipoles at an altitude of 3600

km. In 1981, the antenna was converted to geodetic use

as one of the first two VLBI stations of the National

Geodetic Survey Project POLARIS. Westford has continued to perform geodetic VLBI observations on a regular basis since 1981. Westford has also served as a test

bed in the development of new equipment and techniques now employed in geodetic VLBI worldwide.

Funding for geodetic VLBI at Westford is provided by

the NASA Space Geodesy Program.

MIT Haystack Observatory

Westford Antenna

IVS 2013 Annual Report

Fig. 1 The radome of the Westford antenna.

Table 1 Location and addresses of the Westford antenna.

Longitude 71.49◦ W

Latitude 42.61◦ N

Height above m.s.l. 116 m

MIT Haystack Observatory

Off Route 40

Westford, MA 01886-1299 U.S.A.

http://www.haystack.mit.edu

2 Technical Parameters of the Westford

Antenna and Equipment

The technical parameters of the Westford antenna,

which is shown in Figure 2, are summarized in Table 2.

The antenna is enclosed in a 28-meter diameter airinflated radome made of 1.2 mm thick Teflon-coated

fiberglass—see Figure 1. When the radome is wet, system temperatures increase by 10–20 K at X-band and

by a smaller amount at S-band. The major components

184
Westford Antenna 185

Fig. 2 Wide-angle view of the Westford antenna inside the

radome. The VLBI S/X receiver is located at the prime focus.

The subreflector in front of the receiver is installed when observing with the TAL receiver (see Section 4), which is located at the

Cassegrain focus.

Table 2 Technical parameters of the Westford antenna for

geodetic VLBI.

Parameter Westford

primary reflector shape symmetric paraboloid

primary reflector diameter 18.3 meters

primary reflector material aluminum honeycomb

S/X feed location primary focus

focal length 5.5 meters

antenna mount elevation over azimuth

antenna drives electric (DC) motors

azimuth range 90◦ −470◦

elevation range 4

◦ −87◦

azimuth slew speed 3

◦

s

−1

elevation slew speed 2

◦

s

−1

X-band system S-band system

frequency range 8180-8980 MHz 2210-2450 MHz

Tsys at zenith 50–55 K 70–75 K

aperture efficiency 0.40 0.55

SEFD at zenith 1400 Jy 1400 Jy

of the VLBI data acquisition system are a Mark IV

electronics rack, a Mark 5B recording system, and a

Pentium-class PC running PC Field System version

9.10.2. The primary frequency and time standard is

the NR-4 hydrogen maser. A CNS Clock GPS receiver

system provides a 1 pps reference clock to which the

maser 1 pps is compared.

Westford also hosts the WES2 GPS site of the IGS

network. A Dorne-Margolin chokering antenna is located on top of a tower ∼60 meters from the VLBI

antenna, and a LEICA GRX1200 Reference Station receiver acquires the GPS data.

3 Westford Staff

The personnel associated with the geodetic VLBI program at Westford and their primary responsibilities are:

Chris Beaudoin broadband development

Joe Carter antenna servo support

Brian Corey VLBI technical support

Kevin Dudevoir pointing system software

Dave Fields technician, observer

Alex Burns technician, observer

Glenn Millson observer

Arthur Niell principal investigator

Michael Poirier site manager

Colin Lonsdale site director

4 Standard Operations

From January 1, 2013, through December 31, 2013,

Westford participated in 52 standard 24-hour sessions.

Westford regularly participated in IVS-R1, IVS-R&D,

IVS-T2, and RD-VLBA observations.

Use of the Westford antenna is shared with the Terrestrial Air Link (TAL) Program operated by the MIT

Lincoln Laboratory. In this project, Westford serves as

the receiving end on a 42-km long terrestrial air link

designed to study atmospheric effects on the propagation of wideband communications signals at 20 GHz.

IVS 2013 Annual Report
186 Poirier

5 Research and Development

In its role as a test bed for VLBI developments the

Westford antenna was implemented several times during the year with the VGOS broadband feed assembly

and used successfully as the second element of the interferometer with the GGAO 12-m VGOS system.

The first VGOS geodetic observations were scheduled and observed in October 2012. Two six-hour sessions were run on successive days. The initial results

agree at the few millimeter level, consistent with the

expected performance of the two systems. In May 2013

the first 24-hour session was observed. When broken

into four six-hour sections, the session showed geodetic repeatability among the segments of better than 2

mm. An important goal of that session was to demonstrate unattended operation following setup, and the antenna functioned as expected.

The antenna was also equipped with the Mark 6

prototype data recorder for a demonstration of 16 Gbps

recording capability. The equipment has been left in

place for additional Mark 6 testing and development.

6 Outlook

Westford is expected to participate in 87 24-hour sessions in 2014. These will include the 15-day CONT14

campaign and several VGOS sessions, along with the

occasional fringe test and support of the VGOS broadband development program.

Westford is planning to upgrade the PC Field System and complete the pointing system upgrade, which

will facilitate compatibility with the VGOS/MCI system to be installed on the Westford antenna.

The Westford broadband system will see several

upgrades in 2014, including improvements to the Dewar, implementation of noise diode calibration, and

separation of the RF signal path into two bands to reduce senstivity to S-band RFI.

Acknowledgements

I would like to thank Arthur Niell, Christopher Beaudoin, and Chester Ruszczyk for their contributions to

this report.

IVS 2013 Annual Report
Geodetic Observatory Wettzell - 20-m Radio Telescope and Twin

Telescopes

Alexander Neidhardt 1, Gerhard Kronschnabl 2, Raimund Schatz 1, Torben Schuler  ̈

2

Abstract In 2013 the 20-m radio telescope at the

Geodetic Observatory Wettzell, Germany contributed

again very successfully to the IVS observing program.

2013 was the anniversary year of the antenna as it

started its operations in the year 1983. Technical

changes, developments, improvements, and upgrades

have been made to increase the reliability of the

entire VLBI observing system. Therefore, a complete

shutdown was necessary in the months from July to

September to replace the complete servo and gear

system. In parallel the new Twin radio Telescope

Wettzell (TTW) was officially inaugurated during a

ceremony with international guests. Additionally, first

light and correlation tests were successfully performed

in August.

1 General Information

The 20-m Radio Telescope in Wettzell (RTW) is an

essential component of the Geodetic Observatory

Wettzell (GOW) and is jointly operated by Bundesamt fur Kartographie und Geod  ̈ asie (BKG) and  ̈

Forschungseinrichtung Satellitengeodasie (FESG)  ̈

of the Technische Universitat M  ̈ unchen (Technical  ̈

University Munich). In addition to the RTW an ILRS

laser ranging system, several IGS GPS permanent

stations, a large laser gyroscope G (ringlaser) and

the corresponding local techniques, e.g. time and

1. Forschungseinrichtung Satellitengeodasie (FESG), Technis-  ̈

che Universitat M ̈ unchen  ̈

2. Bundesamt fur Kartographie und Geod  ̈ asie (BKG)  ̈

RTW/TWIN Wettzell Network Station

IVS 2013 Annual Report

frequency, meteorology and super conducting gravity

meters, etc., are also being operated. Currently also

the first antenna of the fully VLBI2010-compliant

Twin radio Telescope is in an operational test phase. It

should extend the observation possibilities according

to the technical suggestions of the IVS Working Group

3 (WG3) and the VLBI Global Observing System

(VGOS) observations.

Within the responsibility of the GOW are the TIGO

system in Concepcion, Chile, operated mainly together  ́

with the Universidad de Concepcion (see separate re-  ́

port about TIGO), and the German Antarctic Receiving Station (GARS) O’Higgins on the Antarctic peninsula, operated together with the German Space Center

(DLR) and the Institute for Antarctic Research Chile

(INACH) (see separate report about O’Higgins).

2 Staff

The staff of the GOW consists in total of 34 members

(excluding students) for operations, maintenance, and

repair issues and for improvement and development of

the systems. The staff operating RTW is summarized in

Table 1. In 2013, two chief engineers were appointed

to be responsible for the technical issues at the two radio telescope systems of the GOW. Christian Plotz took  ̈

over the duty for the 20-m RTW and Gerhard Kronschnabl for the TTW.

Until March 2013, one additional engineer was on

a research position which was funded by the “Novel

EXploration Pushing Robust e-VLBI Services” (NEXPReS) project in cooperation with the Max-PlanckInstitute for Radioastronomy (MPIfR), Bonn. Another

research position, which is partly involved in VLBI

187
188 Neidhardt et al.

Table 1 Staff - members of RTW.

Name Affiliation Function Mainly

working for

Torben Schuler  ̈ BKG head of the GOW GOW

(since January 2013)

Alexander Neidhardt FESG head of the VLBI group RTW, TTW

and VLBI station chief

Erhard Bauernfeind FESG mechanical engineer RTW

Ewald Bielmeier FESG technician RTW

Gerhard Kronschnabl BKG electronic engineer TTW, RTW,

(chief engineer TTW) TIGO

Christian Plotz  ̈ BKG electronic engineer O’Higgins,

(chief engineer RTW) RTW, TTW

Raimund Schatz FESG software engineer RTW

Walter Schwarz BKG electronic engineer RTW,

WVR)

Reinhard Zeitlhofler  ̈ FESG electronic engineer RTW

Martin Ettl FESG/ Computer scientist NEXPReS

MPIfR (until March 2013) (EU FP7)

Jan Kodet FESG appl. phys. engineer DFG FOR1503

Gordon Klingl FESG/ student Operator

BKG RTW/SLR

Yvonne Klingl FESG/ student Operator

BKG RTW/SLR

developments, is founded by the DFG research group

FOR1503 about reference systems, local ties, and colocation on ground and space.

3 Observations in 2013

The 20-m RTW has been supporting the geodetic VLBI

activities of the IVS and partly other partners, such

as the EVN, for almost 30 years. All successfully observed sessions in the year 2013 are summarized in

Table 2. After the repair of the bearings in 2010, it

was also necessary to replace the gears, the motors, the

servo system, and the control system with a new, stateof-the-art technique. This was realized in the months

from July to September 2013. Nevertheless, the telescope is in a very good and stable state. The main priority in operations was participation in all daily onehour INTENSIVE-sessions (INT) in order to determine

UT1-UTC. According to the implementation of a Field

System extension for remote control, weekend INTENSIVEs were partly done in the new observation modes

by remote attendance, remote control from students

at the laser ranging system (WLRS), or completely

unattended. Meanwhile, all data are transferred with eVLBI techniques. RTW now routinely uses the Internet

connection capacities of 1 Gbit/sec for the e-transfers

with the Tsunami protocol to the correlators in Bonn,

Tsukuba, Haystack, and Washington.

Table 2 RTW observations in 2013.

program number of special program number of

24h-sessions 1h-sessions

IVS R1 40 1h-INT1 179

IVS R4 41 1h-INT2/K 56

IVS T2 6 1h-INT3/K 25

IVS R&D 7 VEX/MEX/RadioAstron 31

RDV/VLBA 3 VLBA102 24

EUROPE 5 Satellite tracking 1

total 103 total (in hours) 316

(in hours) 2472

In addition to the standard sessions, RTW was active for other special observations such as the tracking

of the ESA Venus Express (VEX) spacecraft, the Mars

Express (MEX) spacecraft (Phobos fly-by) and the RadioAstron satellite for the EVN. More progress was

possible for the tracking of Glonass and GPS satellites.

Additional developments of an L-band receiver and the

activation of a permanent satellite tracking mechanism,

using the new antenna control unit after the modification of the RTW, enabled frequent observations. A cooperation with the technical university in Vienna also

allowed to extend the scheduling module of the Vienna

VLBI Software (VieVS) to produce VEX files for satellite observations.

4 Technical Improvements and

Maintenance

Regularly, tasks and maintenance days (obtaining replacements for the hardware, 8-pack repair, gear maintenance, exchange of motors after reaching their lifetime, NASA Field System updates, cryo-system maintenance, servo replacements, and improvements for eVLBI issues) were scheduled for the usual maintenance work. As the components of the servo system

were overaged, it was possible to commission a replacement of the whole system and to upgrade it to

a similar, modern technique such as the one installed

in the Twin telescopes. The upgrade was performed

by the company Vertex Antennentechnik GmbH, Duisburg, Germany from July to September. During this upgrade the gears for the azimuth and elevation axes were

replaced. The new gears have new AC-servos and a

IVS 2013 Annual Report
Wettzell - 20-m and Twin Radio Telescopes 189

completely digital control system. Therefore the complete servo and control racks were replaced and the cable wrap was reconfigured. As a new Twin-like antenna

control unit controls the whole system, the station computer software was re-written. The new software supports the classic tracking modes and additional satellite

tracking possibilities and modes, which reduce power

consumption for the slewing between sources with optimal acceleration behavior. In addition to the upgrade

of the servo system, the complete surface of the reflector and sub-reflector was polished and varnished again.

To improve the de-icing of the reflector, the heating

system in dedicated reflector panels was replaced.

Fig. 1 Some replacement work at the RTW: new setup of the

cable wrap (left), replacement of the gears and motors (upper

right), and new varnishing of the reflector surface (lower right).

Upgrades and repairs were also necessary for the

Mark IV data acquisition rack. The revision of the replacement dewar systems for Wettzell and O’Higgins

were completed by the labs at the astronomical observatory in Yebes, Spain.

The usage of the EVN-PC for e-transfer was

continuously extended. In addition the usage of

e-transfer for the 24-hour sessions to the correlators

in Bonn, Haystack, Washington, and Tsukuba was

routinely used with up to 600 Mbit per second. A

combination of the Mark 5 software “fuseMk5” and

the communication protocol “Tsunami” is used on a

regular Mark 5B system.

The usage of the new Digital Baseband Converters

(DBBC) was forced. Several test data were correlated

at the Bonn correlator to check functionality and quality (especially in combination with the Twin operation

tests). Additionally new CoMo boards were installed

to upgrade to a standard version of the equipment. The

development is still under progress.

The remote control software “e-RemoteCtrl” was

also extended, mainly by the TUM. In close cooperation with the developers of the NASA Field System and

with other test sites at Australia (e.g. Hobart, Katherine, and Yarragadee) new features were established.

The AuScope network and the Wettzell site already

use the software routinely. The software development

was funded in task 3 of work package 5 of the NEXPReS project and is performed in cooperation with the

MPIfR.

Another new field is the preparation for tracking

of global navigation satellites. Therefore new amplifier and receiver boards were improved. These can be

used after the waveguides for S-band to receive the Lband of the satellite. Additionally the software is now

able to track satellites permanently, using orbits in the

Two-line Elements format.

5 The TWIN Radio Telescope Wettzell

(TTW)

The Twin Telescope Wettzell project is Wettzell’s realization of a complete VLBI2010 conformity. The mechanical system is now completely functional, and the

installation work of the receiving and the data acquisition systems was continued. The new tri-band horn

was put into operation. Quality checks together with

the company Vertex Antennentechnik GmbH demonstrated the very good performance of the feed horn in

combination with the antenna for S- and X-band. The

new control room was completely set up to control both

the Twin telescopes and the old 20-m antenna. Additionally connections to the TIGO telescope and to the

AuScope telescopes in Australia was established.

The Twin telescopes started their operational test

phase with an official inauguration with international

guests on April 26th. After the ceremonial act, the Undersecretary of State of the German Ministry of the

Interior Cornelia Rogall-Grothe, the Vice-President of

the Technical University Munich (TUM) Prof. Hans

Pongratz, and the President of the Federal Agency for

Cartography and Geodesy (BKG) Prof. Hansjorg Kut-  ̈

terer symbolically started the operations under a clear

and sunny sky by pushing a red start button.

IVS 2013 Annual Report
190 Neidhardt et al.

Fig. 2 The Twin radio Telescope Wettzell (TTW) as Wettzell’s

realization of a complete VLBI2010 conformity.

Fig. 3 A “symbolic” start of the new telescopes.

The first operational test sessions were then performed in August. The north tower of the Twin telescope joined the regular INT3 session together with the

20-m antenna. To test different digital baseband converters, one session used the Japanese ADS3000 system, while another used the DBBC. The scans were

correlated in Bonn and resulted in good results, which

gave also some hints for improvements of the data

quality. Revised versions of the S-/X-receiver in combination with Ka and dual-polarization are under development. New software components for the new receiver and data acquisition system are designed and under implementation. A new transfer technique with the

Mark 5 software “Jive5ab” from the Joint Institute for

VLBI in Europe (JIVE) allows the sending of recording data from one Mark 5 to another in real-time, which

should be used to record all streams in the new Data

Center in the Twin operations building.

Fig. 4 The new control room and Data Center in the Twin operations building.

The broadband feed horn (Eleven feed) for the second telescope (south tower), which is built by Omnisys

in Sweden, is almost finished and is currently in quality control. Chalmers University recently measured the

radiation patterns and the data of the coherence and

cross-polarization. The feed is expected for 2014.

Within a pilot study, a student of the Applied University Dresden ran a permanent survey of the reference point of the south tower, using two total stations

and 20 to 30 reflectors in the back structure. The analysis showed very good stability over time.

6 Future Plans

Dedicated plans for 2014 are:

• Update of the de-icing control system,

• Upgrade of the RTW for complete remote control

from the Twin control room,

• Completion of the Twin implementations of the

north tower and continuation of the operational

tests, and

• Development of new receiver and system monitoring software.

IVS 2013 Annual Report
Instituto Geografico Nacional of Spain  ́

Jesus G  ́ omez-Gonz  ́ alez  ́

1

, Jose Antonio L  ́ opez-Fern  ́ andez  ́

2

, Francisco Colomer 1, Luis Santos 3

Abstract The National Geographic Institute (IGN)

of Spain has been involved in space geodesy activities since 1995. Since 2008, the new 40-m radio telescope at Yebes Observatory has been a network station for IVS and has participated regularly in IVS campaigns. Currently, IGN is involved in the establishment

of an Atlantic Network of Geodynamical and Space

Stations (project RAEGE). The first antenna, at Yebes

Observatory, has been completed. The construction of

its first receiver (triband, S/X/Ka) has been finished

and is ready to be installed at the telescope. Moreover,

the erection of a second antenna of RAEGE (in Santa

Maria, Azores islands, Portugal) is almost complete. In

order to comply with the VGOS specifications, a new

broadband receiver is being developed at Yebes and is

expected to be available for observations in 2015.

1 General Information

The National Geographic Institute of Spain (Instituto

Geografico Nacional, Ministerio de Fomento), has run  ́

geodetic VLBI programs at Yebes Observatory since

1995, nowadays operating a 40-m radio telescope

which is a network station for IVS. Yebes Observatory

is also the reference station for the Spanish GNSS

network and holds permanent facilities for gravimetry.

A new VLBI2010-type antenna has been built in

1. Instituto Geografico Nacional (IGN)  ́

2. IGN Yebes Observatory

3. Secretaria Regional da Ciencia, Tecnologia e Equipamentos ˆ

(Azores, Portugal)

IGN-Yebes Network Station

IVS 2013 Annual Report

Yebes as part of the RAEGE project (the acronym

RAEGE stands for “Red Atlantica hispano-portuguesa  ́

de Estaciones Geodinamicas y Espaciales”).  ́

2 Current Status and Activities

The 40-m radio telescope has participated in 35 sessions (17 R1, 13 R4, three T2, and two EUROPE). All

the data is being routinely transferred by Internet to the

correlators.

We have purchased 64 Tb of Mark 5 disks to support our participation in the IVS CONT14 campaign.

2.1 RAEGE

IGN, together with the Portuguese colleagues in

DSCIG (Azores Islands), continues the construction

of a network of four new Fundamental Geodynamical and Space Stations. The RAEGE project was

described in previous IVS Annual Reports. The

Spanish-Portuguese VGOS network RAEGE will be

covering three continental plates with sites in Spain

at Yebes (Eurasian Plate) and Tenerife (African Plate)

and in Portugal on the Azorean islands of Santa Maria

(Eurasian Plate) and Flores (North American Plate).

On October 21, 2013, the first VGOS radio telescope of the RAEGE Project was inaugurated in Yebes

by the Spanish Minister of Development, Da Ana Pastor, and the President of the Regional Government of

Castilla-La Mancha, Da Mar ́ıa Dolores de Cospedal.

Both officials unveiled a bronze dedication plaque with

the name “Jorge Juan” for the new radio telescope

191
192 Gomez-Gonz  ́ alez et al.  ́

Fig. 1 RAEGE first radio telescope, “Jorge Juan”, at Yebes Observatory. In the background, the 40-m radio telescope which currently

participates in all IVS campaigns.

(see Figure 2). Jorge Juan was a Spanish Admiral and

cosmographer who participated, together with LaCondomine, in the 18th century expedition to Peru (now

Ecuador) to measure the length of a degree of latitude

at the equator and check the polar flatness of the Earth.

After his return, the Spanish King Carlos III entrusted

him with founding the Royal Observatory in Madrid

(ROM, in 1757); today the observatory is part of the Instituto Geografico Nacional, which – through ROM –  ́

is also the host institute of the Yebes Observatory. The

“Jorge Juan” radio telescope, designed by MT Mechatronics GmbH and mostly built by Spanish companies,

will be fully dedicated to geodetic VLBI. The instrument is the first of four very fast RAEGE telescopes

that will be fully VGOS compliant (see Figure 1).

It will be shortly followed by the antenna in Santa

Mar ́ıa (Azores, see the status of the onsite works in

Figure 3 and the control building in Figure 4), whose

first light is expected in early 2015.

Fig. 2 Bronze dedication plaque for the RAEGE “Jorge Juan”

radio telescope, unveiled on October 21, 2013 by the Spanish

Minister of Development, Da Ana Pastor, and the President of

the Autonomous Regional Government of Castilla-La Mancha,

D

a Mar ́ıa Dolores de Cospedal.

The engineers of the Yebes laboratories have completely designed and built a tri-band receiver and opIVS 2013 Annual Report
IGN - Yebes Station Report 193

Fig. 3 Status of construction of the RAEGE antenna in Santa Maria (Azores islands, Portugal).

Table 1 RAEGE instrumentation parameters.

Parameter Value

RT Diameter 13.2 m

Optics Ring focus

Surface rms 180 μm

Designer MT Mechatronics GmbH

Az/El slew speed 12o/sec / 6o/sec

Receivers triband (S, X, Ka)

dual pol (RCP+LCP)

Band Frequency (GHz) Trec (K)

S band 2.2-2.7 21

X band 7.5-9.0 23

Ka band 28-33 GHz 25

DBBC type European DBBC (IRA/INAF)

Recorder Mark 5B+/Mark 5C

Yebes connectivity 10 Gbit/s fiber

tics for the S (2 GHz), X (8 GHz), and Ka (32 GHz)

frequency bands (see Figure 5). This receiver will be

installed at the Yebes RAEGE telescope, which is expected to become available for the IVS in the first

half of 2014. An identical receiver was built for GSI

Fig. 4 Status of construction of the control and auxiliary buildings of the RAEGE station in Santa Maria.

(Japan), and it will be installed at their new antenna in

Ishioka.

Detailed information on RAEGE is available on the

Web at http://www.raege.net/

IVS 2013 Annual Report
194 Gomez-Gonz  ́ alez et al.  ́

Table 2 Staff in the IGN VLBI group (e-mail: vlbitech@oan.es).

Name Background Role Address∗

Francisco Colomer Astronomer VLBI Project coordinator IGN

Jesus G  ́ omez–Gonz  ́ alez  ́ Astronomer Deputy Director for IGN

Astronomy, Geophysics, and Space Applications

Jose Antonio L  ́ opez–Fdez  ́ Engineer RAEGE Director Yebes

Pablo de Vicente Astronomer VLBI technical coordinator Yebes

Jose Antonio L  ́ opez–P  ́ erez  ́ Engineer Receivers Yebes

Felix Tercero  ́ Engineer Antennas Yebes

Susana Garc ́ıa–Espada Engineer geoVLBI expert Yebes

Javier Lopez–Ramasco  ́ Geodesist Geodesist Yebes

Alvaro Santamar ́ıa Geodesist Geodesist Yebes

Fig. 5 Tri-band (S/X/Ka) receiver, designed and built at the laboratories in Yebes Observatory.

3 IGN Staff Working on VLBI Projects

Table 2 lists the IGN staff who are involved in space

geodesy studies and operations. The VLBI activities

are also supported by other staff such as receiver engineers, computer managers, telescope operators, secretaries, and students.

4 Future Plans

First light of the RAEGE radio telescope at Yebes is

expected in early 2014. The construction of the second

antenna of RAEGE, in Santa Maria (Azores), will also

be completed in 2014.

In order to comply with the VGOS specifications,

a new broadband receiver is being developed at Yebes

and should be available for observations in 2015.

IGN expects to participate in the IVS CONT14

campaign with the Yebes 40-m radio telescope and will

also take part in the early VGOS tests starting in 2015

with the new RAEGE 13.2-m “Jorge Juan” antenna.

RAEGE is to be completed with two more stations, in Tenerife (Canary islands) and Flores (Azores

islands). Site selection for the former is very advanced,

near the city of Tegueste, in the northern and most geologically stable part of the island of Tenerife. Figure 4

displays the project of the station infrastructures, including the radio telescope (under construction at MT

Mechatronics GmbH) and auxiliary buildings for control, time and frequency, gravimeters, etc. The construction of this station is expected in 2016 and the one

in Flores in 2017.

IVS 2013 Annual Report
Zelenchukskaya Radio Astronomical Observatory 2013 IVS

Annual Report

Sergey Smolentsev, Andrei Dyakov

Abstract This report summarizes information on activities at the Zelenchukskaya Radio Astronomical Observatory in 2013. During the previous year a number

of changes were carried out at the observatory to improve some technical parameters and to upgrade some

units to required status. The report also provides an

overview of current geodetic VLBI activities and gives

an outlook for the next year.

1 General Information

Zelenchukskaya Radio Astronomical Observatory

(Figure 1) was founded by the Institute of Applied

Astronomy (IAA) as one of three stations of the

Russian VLBI network QUASAR. The sponsoring

organization of the project is the Russian Academy

of Sciences (RAS). The Zelenchukskaya Radio

Astronomical Observatory is situated in KarachaevoCherkesskaya Republic (the North Caucasus) about

70 km south of Cherkessk, near Zelenchukskaya

village (Table 1). The geographic location of the

observatory is shown on the IAA RAS Web site:

http://www.ipa.nw.ru/PAGE/rusipa.htm. The basic

instruments of the observatory are a 32-m radio

telescope equipped with special technical systems

for VLBI observations, GPS/GLONASS/Galileo

receivers, and an SLR system.

Institute of Applied Astronomy of RAS

Network Station Zelenchukskaya

IVS 2013 Annual Report

Table 1 Zelenchukskaya Observatory location and address.

Longitude 41◦34′

Latitude 43◦47′

Karachaevo-Cherkesskaya Republic

369140, Russia

ipazel@mail.svkchr.ru

Fig. 1 Zelenchukskaya observatory.

2 Technical Staff

Table 2 Staff related to VLBI operations at Zelenchukskaya.

Andrei Dyakov observatory chief

Dmitry Dzuba FS, pointing system control

Anatoly Mishurinsky front end and receiver support

Andrey Mikhailov FS, pointing system control

195
196 Smolentsev and Dyakov

3 Component Description

3.1 Technical and Scientific Information

Characteristics of the radio telescope are presented in

Table 3.

Table 3 Technical parameters of the radio telescope.

Year of construction 2005

Mount AZEL

Azimuth range ±270◦(from south)

Elevation range from −5

◦

to 95◦

Maximum azimuth

- velocity 0.83 ◦/s

- tracking velocity 2.5

′

/s

- acceleration 12.0

′

/s

2

Maximum elevation

- velocity 0.5

◦

/s

- tracking velocity 0.8

′

/s

- acceleration 12.0

′

/s

2

Pointing accuracy better than 10′′

Configuration Cassegrain (with

asymmetrical subreflector)

Main reflector diameter 32 m

Subreflector diameter 4 m

Focal length 11.4 m

Main reflector shape quasi-paraboloid

Subreflector shape quasi-hyperboloid

Main reflector surface accuracy ± 0.5 mm

Frequency range 1.4–22 GHz

Axis offset 3.7±2.0 mm

3.2 Co-location of VLBI, GPS/GLONASS,

and SLR System

The Javad GPS/GLONASS/Galileo receiver with meteo station WXT-510 is in operation (Figure 2). The

SLR system “Sazhen-TM” (Figure 3) at Zelenchukskaya observatory joined the ILRS in March 2012. The

technical parameters of the system are presented in Table 3.

Fig. 2 Javad GPS/GLONASS/Galileo receiver at the Zelenchukskaya observatory.

Fig. 3 “Sazhen-TM” SLR system at Zelenchukskaya observatory observed 744 passes of Lageos, GLONASS et al. and obtained 1278 normal dots.

4 Current Status and Activities during

2013

Zelenchukskaya observatory participates in IVS and

domestic VLBI observational programs. During 2013

Zelenchukskaya station participated in 31 diurnal IVS

sessions — 25 IVS-R4 sessions, two IVS-T2 sessions,

and four EURO sessions.

Zelenchukskaya participated in 48 diurnal sessions

in the frame of the domestic Ru-E program for determination of all Earth orientation parameters and in 349

one-hour Ru-U sessions for obtaining Universal Time

using e-VLBI data transfer. Since April 2013, we have

IVS 2013 Annual Report
Zelenchukskaya IVS Annual Report 197

used e-VLBI data transfer for Zelenchukskaya observational data for the Ru-E 24-hour sessions.

Finally, an antenna tower for the 13.2-m dish was

built.

Fig. 4 Antenna tower for the 13.2-m dish and RT-32 at Zelenchukskaya observatory.

5 Future Plans

Our plans for the coming year are the following:

• To participate in IVS observations including the

CONT14 IVS campaign,

• To carry out domestic observational programs for

obtaining Universal Time daily and for obtaining

Earth orientation parameters weekly with e-VLBI

data transfer,

• To carry out SLR observations of geodetic and navigation satellites,

• To participate in EVN and RADIOASTRON observational sessions,

• To continue geodetic monitoring of the RT-32 parameters,

• To install a WVR, and

• To finish VLBI2010 antenna installation in 2014.

References

1. Finkelstein A., Ipatov A., Smolentsev S. The Network

“Quasar”: 2008-2011 // “Measuring the future”, Proc. of the

Fifth IVS General Meeting, A. Finkelstein, D. Behrend (eds.),

St. Petersburg, “Nauka”, 2008. pp. 39–46.

IVS 2013 Annual Report

Operation Centers

The Bonn Geodetic VLBI Operation Center

A. Nothnagel, A. Muskens  ̈

Abstract The IGGB Operation Center has continued to

carry out its tasks of organizing and scheduling various

observing sessions of the IVS-T2, IVS-OHIG, IVSINT3, and EUROPE series.

1 Center Activities

The IGGB VLBI Operation Center is part of the Institute of Geodesy und Geoinformation of the University

of Bonn, Nußallee 17, D-53115 Bonn, Germany. It has

been organizing and scheduling VLBI observing sessions for almost 30 years. The work of the Operation

Center is closely related to the Bonn Correlator. For

this reason, distribution of media (Mark 5 disk units) to

the stations after correlation is still the most costly part

of the operations since network capacity has remained

constant at 1 Gb/s for financial reasons.

• Measurement of Vertical Crustal Motion in

Europe by VLBI (EUROPE)

Since the late 1980s, a series of special sessions

is regularly being scheduled in Europe for precise

determination of station coordinates and for long

term stability monitoring. This year, six network

observing sessions with Ny-Alesund (six sessions),  ̊

Onsala (four sessions), Metsahovi (one session),

DSS65a (one session), Svetloe (four sessions),

Zelenchukskaya (four sessions), Badary (three

sessions), Effelsberg (two sessions), Wettzell

(five sessions), Simeiz (five sessions), Medicina

Institut fur Geod  ̈ asie und Geoinformation der Universit  ̈ at Bonn  ̈

Bonn Operation Center

IVS 2013 Annual Report

(three sessions), Matera (two sessions), Noto (six

sessions), and Yebes (YEBES40M) (two sessions)

were scheduled employing the frequency setup of

16 channels and 4 MHz bandwidth (identical to the

setup of the IVS-T2 sessions).

• IVS-T2 series

This series was observed roughly every second

month (seven sessions in 2013) primarily for maintenance and stabilization of the VLBI terrestrial

reference frame as well as for Earth rotation monitoring as a by-product. Each station of the global

geodetic VLBI network is planned to participate

in the T2 sessions at least once per year. In view

of the limitations in station days, priority was

given to strong and robust networks with many

sites over more observing sessions. Therefore,

generally 15 to 24 stations have been scheduled

in each session. The scheduling of these sessions

has to take into account that a sufficient number

of observations is planned for each baseline of

these global networks. The recording frequency

setup is 16 channels and 4 MHz channel bandwidth.

• Southern Hemisphere and Antarctica Series

(OHIG):

In February 2013, three sessions of the Southern Hemisphere and Antarctica Series with the

Antarctic stations Syowa (Japanese) and O’Higgins

(German) plus Fortaleza, HartRAO, and Kokee

have been organized (OHIG82-83-84). Furthermore, O’Higgins was also included successfully

in the T2088 session. The (southern) winter

O’Higgins burst (OHIG85-86-87) was scheduled,

but it had to be observed without O’Higgins for

201
202 Nothnagel and Muskens  ̈

various reasons. Other participating stations were

Fortaleza, HartRAO, Kokee, Syowa, HOBART12,

KATH12M, Kokee, WARK12M, TIGOCONC,

and YARR12M. The purpose of these sessions is

the maintenance of the VLBI terrestrial reference

frame (TRF) and the monitoring of Earth rotation

as a by-product. The recording frequency setup

is 16 channels and 4 MHz channel bandwidth.

Due to the fact that Syowa is not able to deliver

the recorded data for nearly one year after the

observations, the correlation and the generation of

the databases is always delayed considerably.

• UT1 determination with near-real-time e-VLBI

(INT3):

The so-called INT3 sessions were originally set up

for the telescopes of Ny-Alesund, Tsukuba, and  ̊

Wettzell for weekly UT1 determinations aiming at

very quick delivery of results. The sessions are always scheduled to start on Monday morning at 7:00

a.m. UT.

Due to maintenance activities at Tsukuba, NyAlesund, and Wettzell, one or more of these  ̊

stations sometimes had to be replaced by other

suitable telescopes. From May to December,

Seshan replaced Tsukuba in 26 sessions. Since

then, Seshan has taken part in the INT3 sessions

on a monthly basis. Svetloe replaced Wettzell

and Ny-Alesund during June to September, and  ̊

Yebes replaced them during August. No suitable

observing configuration could be established for

17 sessions, which had to be canceled entirely.

The operations part of the INT3 sessions also includes rapid data transmission and correlation. The

raw VLBI observation data of four sites is transferred to the Bonn Correlator by Internet connections directly after the session is completed in order

to speed up delivery of the results. The transmission rate is about 400-600 Mb/s from Tsukuba and

Wettzell, 300 Mb/s from Seshan, and 100 Mb/s for

Ny-Alesund. For the latter, the data rate is limited  ̊

due to the use of a radio link for the first part of

the distance. All transmissions share the “last mile”

which is limited to 1 Gb/s due to financial limitations.

Altogether, 33 INT3 sessions were observed and

transmitted successfully in 2013. 96% of the sessions were correlated and the databases delivered

within the first four hours after the end of the observations. A further 2% were completed within ten

hours. The rest took between ten and 48 hours due

to difficulties with networking hardware and/or station and processor problems.

2 Staff

Table 1 Personnel at IGGB Operation Center.

Arno Muskens  ̈ +49-228-525264 mueskens@mpifr.de

Axel Nothnagel +49-228-733574 nothnagel@uni-bonn.de

IVS 2013 Annual Report
CORE Operation Center 2013 Annual Report

Cynthia C. Thomas, Daniel S. MacMillan

Abstract This report gives a synopsis of the activities

of the CORE Operation Center from January 2013 to

December 2013. The report forecasts activities planned

for the year 2014.

1 Changes to the CORE Operation

Center’s Program

The Earth orientation parameter goal of the IVS program is to attain precision at least as good as 3.5 μs for

UT1 and 100 μas for pole position.

The IVS program, which started in 2002, used the

Mark IV recording mode for each session. The IVS

program began using the Mark 5 recording mode in

mid-2003. By the end of 2007, all stations were upgraded to Mark 5. Due to the efficient Mark 5 correlator, the program continues to be dependent on station

time and media. The following are the network configurations for the sessions for which the CORE Operation Center was responsible in 2013:

• IVS-R1: 53 sessions, scheduled weekly and mainly

on Mondays, five to twelve station networks

• RDV: Six sessions, scheduled evenly throughout

the year, 14 to 16 station networks

• IVS-R&D: Ten sessions, scheduled monthly, six to

ten station networks

NVI, Inc.

CORE Operation Center

IVS 2013 Annual Report

2 IVS Sessions from January 2013 to

December 2013

This section displays the purpose of the IVS sessions

for which the CORE Operation Center is responsible.

• IVS-R1: In 2013, the IVS-R1s were scheduled

weekly with five to twelve station networks. During

the year, 19 different stations participated in the

IVS-R1 network, but there were only eight stations

that participated in at least half of the scheduled

sessions—Tigo (51), Ny-Alesund (47), Wettzell  ̊

(41), Fortaleza (40), Westford (39), Hobart12 (28),

Kokee (28), and Katherine (26). Aira participated

in the IVS-R1 sessions for the first time during

2013.

The purpose of the IVS-R1 sessions is to provide

weekly EOP results on a timely basis. These sessions provide continuity with the previous CORE

series. The “R” stands for rapid turnaround because

the stations, correlators, and analysts have a commitment to make the time delay from the end of

recording to the results as short as possible. The

time delay goal is a maximum of 15 days. Eightyone percent of the IVS-R1 sessions were completed

in 15 or fewer days. The remaining 19% were completed in 16 to 24 days [16 days (four), 17 days

(one), 20 days (two), 23 days (two), and 24 days

(one)]. Participating stations are requested to ship

disks to the correlator as rapidly as possible or to

transfer the data electronically to the correlator using e-VLBI. The “1” indicates that the sessions are

mainly on Mondays.

• RDV: There are six bi-monthly coordinated astrometric/geodetic experiments each year that use the

203
204 Thomas and MacMillan

full ten-station VLBA plus up to six geodetic stations.

These sessions are being coordinated by the geodetic VLBI programs of three agencies: 1. USNO performs repeated imaging and correction for source

structure; 2. NASA analyzes this data to determine

a high accuracy terrestrial reference frame; and 3.

NRAO uses these sessions to provide a service to

users who require high quality positions for a small

number of sources. NASA (the CORE Operation

Center) prepares the schedules for the RDV sessions.

• R&D: The purpose of the ten R&D sessions in

2013, as decided by the IVS Observing Program

Committee, was to support mixed mode observing

(RD1301), vet sources for the good geodetic

catalog (RD1302 and RD1304), vet sources for the

good geodetic catalog and GAIA proposal sources

(category 4) (RD1303), observe linked sources

between GAIA and ICRF-2 (RD1305 through

RD1308), and test the 512 Mbps recording mode

for the CONT14 Campaign.

3 Current Analysis of the CORE Operation

Center’s IVS Sessions

Table 1 gives the average formal errors for the R1, R4,

RDV, R&D, and T2 sessions from 2013. The R1 session formal uncertainties are not significantly different

from the 2011-2012 errors. The R4 uncertainties for the

2012-2013 sessions are much better than for 2011. R4

stations performed better in 2012-2013 than in 2011,

where 37 sessions lost one or more stations from the

original scheduled network. R1 uncertainties for 2011-

2013 could be reduced if we used a GPS a priori model

to obtain the post-earthquake behavior at Tsukuba instead of estimating the TSUKUB32 position for each

session, thereby weakening its contribution to EOP.

RDV uncertainties are about 10% larger for 2013

than for 2011 and 2012. The RDV formal errors are

still better than the other experiment series. This is due

to the large number of stations in the RDV sessions as

well as to better global geometry. T2 uncertainties for

X-pole and nutation in longitude are clearly better in

2013 than for 2011-2012. For comparison, we also included the formal uncertainties for the CONT11, which

are much better than any of the networks discussed

above that observed in 2013.

Table 2 shows EOP differences with respect to the

IGS series for the R1, R4, T2, RDV, and CONT11

series. The WRMS differences were computed after

removing a bias, but estimating rates does not affect

the residual WRMS significantly. Except for the R4

X-pole, R1 and R4 series have worse WRMS agreement in X-pole, Y-pole, and LOD for 2013 than for

these series since 2000. Part of this may be explained

by the treatment of TSUKUB32 in solutions as discussed above. Adopting the improved GPS a priori

model strategy above improves the R1 agreement with

IGS by 20%. It is not understood why the R4 Y-pole

WRMS difference relative to IGS is so much greater

for 2013 than for the long-term series. Both the X-pole

and Y-pole biases of the R1 and R4 sessions relative

to IGS differ by 70 uas, which is much greater than

the uncertainty of the bias estimates. Of all the series,

the RDV series has the best WRMS agreement of Xpole and Y-pole with IGS estimates in 2013 and for

the full period, 2000-2013. For comparison with the

2013 sessions discussed here, we included the statistics for the 15 CONT11 sessions, which shows the best

WRMS agreement with IGS. This is expected because

the CONT11 network 1) has better geometry and 2) is

unchanged over the period of 15 days of continuous

observing.

4 The CORE Operations Staff

Table 3 lists the key technical personnel and their responsibilities so that everyone reading this report will

know whom to contact about their particular question.

5 Planned Activities during 2014

The CORE Operation Center will continue to be responsible for the following IVS sessions during 2014:

• The IVS-R1 sessions will be observed weekly and

recorded in Mark 5 mode.

• The IVS-R&D sessions will be observed ten times

during the year.

• The RDV sessions will be observed six times during the year.

IVS 2013 Annual Report
CORE Operation Center Report 205

Table 1 Average EOP Formal Uncertainties for 2013.

Session Num X-pole Y-pole UT1 DPSI DEPS

Type (μas) (μas) (μs) (μas) (μas)

R1 51 67(73,67) 66(63,65) 3.1(3.4,3.0) 105(110,111) 42(44,45)

R4 5l 68(70,84) 66(67,75) 2.9(2.8,3.2) 120(124,160) 49(49,65)

RDV 6 54(48,49) 54(48,46) 2.8(2.5,2.5) 82(68,75) 33(28,30)

T2 6 67(83,89) 66(66,90) 3.4(3.9,4.3) 130(146,176) 50(57,67)

CONT11 15 39 38 1.7 42 17

Values in parentheses are for 2012 and then 2011.

Table 2 Offset and WRMS Differences (2013) Relative to the IGS Combined Series.

X-pole Y-pole LOD

Session Type Num Offset WRMS Offset WRMS Offset WRMS

(μas) (μas) (μas) (μas) (μs/d) (μs/d)

R1 51(620) -103(-1) 124(104) 6(12) 122(91) 2.6(0.8) 22(17)

R4 51(618) -33(-22) 97(113) 72(21) 134(115) 0.8(1.8) 18(18)

RDV 6(84) 41(58) 68(81) -46(2) 70(68) 2.1(-0.2) 12(14)

T2 6(81) 0.3(3) 108(141) 47(5) 128(117) 10.8(2.2) 16(19)

CONT11 15 42 36 9 29 7.0 7

Values in parentheses are for the entire series (since 2000) for each session type.

Table 3 Key Technical Staff of the CORE Operations Center.

Name Responsibility Agency

Dirk Behrend Organizer of CORE program NVI, Inc./GSFC

Brian Corey Analysis Haystack

Ricky Figueroa Receiver maintenance ITT Exelis

John Gipson SKED program support and development NVI, Inc./GSFC

Frank Gomez Software engineer for the Web site Raytheon/GSFC

David Gordon Analysis NVI, Inc./GSFC

Ed Himwich Network Coordinator NVI, Inc./GSFC

Dan MacMillan Analysis NVI, Inc./GSFC

Katie Pazamickas Maser maintenance ITT Exelis

David Rubincam Procurement of materials necessary for CORE operations GSFC/NASA

Braulio Sanchez Procurement of materials necessary for CORE operations GSFC/NASA

Dan Smythe Tape recorder maintenance Haystack

Cynthia Thomas Coordination of master observing schedule and preparation of

observing schedules

NVI, Inc./GSFC

IVS 2013 Annual Report
NEOS Operation Center

David M. Hall, Merri Sue Carter

Abstract This report covers the activities of the NEOS

Operation Center at USNO for 2013. The Operation

Center schedules IVS-R4 and the INT1 Intensive experiments.

1 VLBI Operations

NEOS operations in the period covered consisted,

each week, of one 24-hour duration IVS-R4 observing

session, on Thursday-Friday, for Earth Orientation,

together with five daily one-hour duration “Intensives”

for UT1 determination, Monday through Friday.

In 2013, the operational IVS-R4 network included

VLBI stations at Kokee Park (Hawaii), Wettzell

(Germany), Ny-Alesund (Norway), TIGO (Chile),  ̊

Fortaleza (Brazil), Tsukuba (Japan), Svetloe, Badary

and Zelenchukskaya (Russia), Hobart, Katherine and

Yarragadee (Australia), Yebes (Spain), and Matera and

Medicina (Italy). A typical R4 consisted of eight to

twelve stations.

The regular stations for the weekday IVS Intensives were Kokee Park and Wettzell. Intensives including Kokee Park, Wettzell, and Svetloe were occasionally scheduled in order to characterize the Kokee Park

— Svetloe baseline so that Svetloe can be used as an

alternate for Wettzell should it be needed. Odd-day Intensives were scheduled with the scheduling technique

used since 2000; even-day Intensives were scheduled

U.S. Naval Observatory

NEOS Operation Center at USNO

IVS 2013 Annual Report

with an experimental scheduling technique developed

in 2009.

The Operation Center updated the version of sked

as updates became available.

All sessions are correlated at the Washington Correlator, which is located at USNO and is run by NEOS.

Table 1 Experiments Scheduled during 2013.

Number of Experiments Type

52 IVS-R4 experiments

227 Intensives

2 Staff

D. M. Hall and M. S. Carter are the only staff members of the NEOS Operation Center. Mr. Hall is responsible for the overall management, and Carter makes

the schedules. M. S. Carter is located at the USNO

Flagstaff Station (NOFS).

206
Correlators

The Bonn Astro/Geo Correlator

Laura La Porta 1, Walter Alef 2, Alessandra Bertarini 1,2, Simone Bernhart 1,2, Gabriele Bruni 2, Arno Muskens  ̈

1

,

Helge Rottmann 2, Alan Roy 2, Gino Tuccari 2,3

Abstract The Bonn Distributed FX (DiFX) correlator

is a software correlator operated jointly by the MaxPlanck-Institut fur Radioastronomie (MPIfR), the In-  ̈

stitut fur Geod  ̈ asie und Geoinformation der Universit  ̈ at ̈

Bonn (IGG), and the Bundesamt fur Kartographie und  ̈

Geodasie (BKG) in Frankfurt, Germany.  ̈

1 Introduction

The Bonn correlator is located at the MPIfR1in

Bonn, Germany. It is operated jointly by the MPIfR

and the BKG2in cooperation with the IGG3. It is

a major correlator for geodetic observations and

astronomical projects (for instance, those involving

pulsar gating, millimeter wavelengths, astrometry, and

RadioAstron4).

1. Institut fur Geod  ̈ asie und Geoinformation der Universit  ̈ at ̈

Bonn

2. Max-Planck-Institut fur Radioastronomie  ̈

3. Istituto di Radioastronomia - INAF

Bonn Correlator

IVS 2013 Annual Report

1 http://www.mpifr-bonn.mpg.de/

2 http://www.bkg.bund.de/

3 http://www.gib.uni-bonn.de/

4 http://www.asc.rssi.ru/radioastron/

2 Present Correlator Capabilities

The DiFX correlator5 was developed at Swinburne

University in Melbourne by Adam Deller and other

collaborators. It was adapted to the VLBA operational

environment by Walter Brisken and the NRAO staff,

and it is constantly updated by the worldwide DiFX

developers group. In Bonn, the DiFX is running on

a High Performance Compute Cluster (HPC cluster),

whose features are:

• 60 nodes (eight compute cores each)

• four TFlops in the Linpack benchmark test

• 20 Gbps Infiniband interconnection

• 13 RAIDs (about 480 TB storage capacity)

• one control node for correlation (fxmanager)

• one computer (frontend) for executing parallelized

jobs on the cluster, e.g. post-correlation applications

• one control computer (appliance) for installing and

monitoring the cluster

• closed loop rack cooling

The HPC cluster connected via 20 Gbps Infiniband to

14 Mark 5 units6is used for playing back the data. If

more than 14 playback units are required, and in the

case of e-VLBI, the data are copied to the RAIDs prior

to correlation. The Mark 5 units can deal with all types

of Mark 5 formats (A/B/C). The disk modules in the

Mark 5 are controlled via the NRAO’s mk5daemon

program. The available functionality includes recording the directories of the modules, resetting and rebooting the units, and module conditioning. In 2013, the

5 DiFX: A Software Correlator for Very Long Baseline Interferometry using Multiprocessor Computing Environments, 2007,

PASP, 119, 318

6 http://www.haystack.mit.edu/tech/vlbi/mark5/

209
210 La Porta et al.

Software Development Kit (SDK) of the Mark 5 units

was upgraded to version 9.1, which enables the usage

of larger disks. A summary of the capabilities of the

DiFX software correlator is presented in Table 1.

3 Staff

The people in the Geodesy VLBI group at the Bonn

correlator are:

Arno Muskens  ̈ - group leader and scheduler of T2,

OHIG, EURO, and INT3 sessions.

Simone Bernhart - support scientist, e-transfer supervision and operations, experiment setup and evaluation

of correlated data for geodesy and RadioAstron, and

media shipping.

Alessandra Bertarini - Friend of the correlator, experiment setup and evaluation of correlated data for both

astronomy (e.g. APEX) and geodesy, and digital baseband converter (DBBC) testing.

Laura La Porta - support scientist, e-transfer supervision and operations, geodetic experiment setup and

evaluation of correlated data, media shipping, DBBC

testing, and programmer for automated preparation of

correlator reports.

The people in the astronomical group at the Bonn

correlator are:

Walter Alef - head of the VLBI technical department,

computer systems, and cluster administration.

Alan Roy - deputy group leader, support scientist

(water vapor radiometer, technical assistance, development of FPGA firmware for linear to circular

polarization conversion, and project manager for

equipping APEX for millimeter VLBI).

Gabriele Bruni - support scientist for RadioAstron,

experiment setup and evaluation of correlated data,

and e-transfer supervision and operations.

Armin Felke - FPGA programming for DBBC.

Heinz Fuchs - correlator operator, responsible for the

correlator operator schedule, daily operations, and

media shipping.

David Graham - consultant (technical development,

DBBC development, and testing).

Rolf Martens  ̈ - technician maintaining cluster hardware and Mark 5 playbacks.

Helge Rottmann - software engineer for correlator

development and operation, cluster administration,

DBBC and RDBE control software, and the Field

System.

Hermann Sturm - correlator operator, correlator

support software, media shipping, and Web page

development.

Gino Tuccari - guest scientist from INAF, DBBC

development, and DBBC project leader.

Jan Wagner - PhD student, support scientist for

APEX, DBBC development, and DiFX developer.

Michael Wunderlich - engineer, development and

testing of DBBC components.

4 Status

Experiments: In 2013 the Bonn group correlated 54

R1, six EURO, seven T2, six OHIG, 35 INT3, and

about 40 astronomical sessions (including data from

Early-Science and the first two A0-1 projects of RadioAstron).

e-VLBI: The total disk space available for e-VLBI data

storage at the correlator is about 130 TB. The Web page

that shows current active e-transfers and helps to coordinate transfer times and rates on a first come-first

served basis7, reports also the storage capacity at the

three correlators (Washington, Haystack, and Bonn).

On average ≥ 80 % of the stations do e-transfer. The

average amount of e-transferred data per week is about

8 TB, considering only the regular INT3 and R1 experiments. Most transfers are done using the UDPbased Tsunami protocol, and the achieved data rates

range from 100 Mb/s to 800 Mb/s. The upgrade of the

1 Gbps Internet connection to meet the requirements of

VLBI2010 Global Observing System (VGOS) has not

been realized yet, due to funding issues.

DiFX software correlator: The DiFX software correlator has been operated in Bonn since 2009 and is continuously updated. The stable DiFX release 2.2 was installed in 2013.

Two other branch versions of the DiFX software

correlator are available in Bonn: a DiFX version for

RFI mitigation, developed by J. Wagner, and a DiFX

version dedicated to RadioAstron (a Russian satellite

that observes in conjunction with ground-based telescopes), developed by J. Anderson.

DBBC: The Bonn group is involved in the develop7 http://www3.mpifr-bonn.mpg.de/cgi-bin/showtransfers.cgi

IVS 2013 Annual Report
The Bonn Correlator 211

Table 1 Correlator capabilities.

Playback Units

Number available 14 Mark 5 (four Mark 5A, two Mark 5B, eight Mark 5C)

Playback speed 1.5 Gbps

Formats Mark 5A, Mark 5B, VDIF

Sampling 1 bit, 2 bits

Fan-out (Mark 5A) 1:1, 1:2, 1:4

No. channels ≤ 16 USB and/or LSB

Bandwidth/channel (2, 4, 6, 8, 32) MHz

Signal Single-, dual-frequency; all four Stokes parameters for circular

and linear polarization

Correlation

Geometric model CALC 9

Phase cal Phase-cal extraction of all tones in a sub-band simultaneously

Pre-average time Milliseconds to seconds

Spectral channels Max no. of FFT tested 218

Export FITS export. Interface to Mk IV data format which enables the use of

geodetic analysis software and Haystack fringe fitting program.

Pulsar Pulsar with incoherent de-dispersion

ment and testing of the DBBC for the European VLBI

Network (EVN) and geodesy. The DBBC is designed

as a full replacement for the existing analog BBCs.

The following stations have already bought one or

more DBBCs: APEX, AuScope (Australia), HartRAO

(Africa), Effelsberg, Medicina, Onsala, Pico Veleta,

Yebes, Wettzell, and Warkworth. Recently, the HartRAO and Onsala stations switched to DBBCs also for

geodetic experiments, whereas Yebes, Medicina, and

Wettzell are still in the testing process. The remaining

stations routinely use the DBBCs.

A prototype of the next generation DBBC

(DBBC3-L) was realized, which can handle a larger

bandwidth of 4 GHz. In a second stage the DBBC3-H

will be able to sample the full frequency range of 1 to

14 GHz without performing any downconversion.

APEX: The Bonn VLBI group has equipped the

APEX telescope for VLBI observations at 1 mm. In

2013 APEX got into science operations by taking

part in the Event Horizon Telescope (EHT) campaign.

Observations were carried out at 4 Gbps, lasted about

50 hours and provided good detections for several

sources (see Figure 1 for an example).

5 Outlook for 2014

DiFX Correlator: A proposal to replace the now six

year old cluster with a more modern system is being

prepared. Two Mark 6 units with 16 Gbps recording

capability have been bought to comply with VGOS

requirements. The Mark 6 units will be installed and

tested. The RadioAstron DiFX branch versions will be

merged with the current development version of the

DiFX.

e-VLBI: Purchase of a new 80 TB RAID for RadioAstron.

DBBC: Continue testing for the stations that recently

acquired DBBCs. Wide bandwidth modes are also under test. Testing of DBBC3.

Phasing up ALMA: The group is involved in an international project to add array phasing capability to

ALMA. ALMA will record with a data rate of 64 Gbps,

thus being an extremely sensitive station in 1 mm VLBI

experiments, which will be correlated in Bonn.

IVS 2013 Annual Report
212 La Porta et al.

Mk4/DiFX fourfit 3.8 rev 805 BLLAC.xfspqo, No0002, AF

APEX - CARMAFL, fgroup B, pol LL

2

66.9

417.280

1.257

-152.8

0.0e+00

0.004822

0.005357

-0.081631

 0.00

228881.0000

0.640

a25gl

16383

2013:084

121502.56

122159.84

121830.00

2013:352:134612

2013:354:081235

2013:182:123017

22h02m43.2914s

+42 ̊16’39.980"

Fringe quality

SNR

Int time

Amp

Phase

PFD

Delays (us)

SBD

MBD

Fringe rate (Hz)

Ion TEC 

Ref freq (MHz)

AP (sec)

Exp.

Exper #

Yr:day

Start

Stop

FRT

Corr/FF/build

RA & Dec (J2000)

Fig. 1 1 mm observations of the source BL Lacertae in March 2013, baseline APEX-Combined Array for Research in Millimeterwave Astronomy (CARMA, California). The fringe spacing was 29 microarcseconds, the finest yet achieved.

IVS 2013 Annual Report
Haystack Observatory VLBI Correlator

Mike Titus, Roger Cappallo, Brian Corey, Kevin Dudevoir, Arthur Niell, Jason SooHoo, Alan Whitney

Abstract This report summarizes the activities at the

Haystack Correlator during 2013. Highlights include

the transition from Mark IV to DiFX for full time production and the decommissioning of the Mark IV in

July, enhancement of the DiFX cluster with additional

disk space for increased flexibility, and processing of

two 24-hour broadband delay experiments and new uVLBI Galactic Center observations that included several new antennas. Non-real-time e-VLBI transfers and

software support of other correlators continued.

1 Introduction

The Mark IV and DiFX VLBI correlators of the MIT

Haystack Observatory, located in Westford, Massachusetts, are supported by the NASA Space Geodesy

Program and the National Science Foundation. They

are dedicated mainly to the pursuits of the IVS, with

a smaller fraction of time allocated to processing

radio astronomy observations for the Ultra High

Sensitivity VLBI (u-VLBI) project. The Haystack

correlators serve as development systems for testing

new correlation modes, for hardware improvements

such as the Mark 6 system, and in the case of the Mark

IV, for diagnosing correlator problems encountered

at Haystack and at the identical correlator at the U.S.

Naval Observatory. This flexibility is made possible

by the presence on-site of the team that designed the

Mark IV correlator hardware and software. Some

MIT Haystack Observatory

Haystack Correlator

IVS 2013 Annual Report

software support is provided to the Max Planck

Institute for Radioastronomy in Bonn, Germany and

to the general IVS community, for DiFX processing of

IVS experiments.

2 Summary of Activities

2.1 DiFX Transition

The switch over to full-time DiFX production occurred

in early July. The first IVS experiment fully processed

on DiFX was RD1304, and all correlation is now done

on the DiFX cluster. Because our cluster setup differs

greatly from the other large installations on which our

the DiFX software suite is based, various programs had

to be modified from their default behaviors in order to

work in the Haystack production environment. A particularly critical one was genmachines, which had to

be modified to re-allocate core processors efficiently

for us. startdifx also had to be adapted, and problems

with corrupt module directories and Mark 5 playback

unit readpos errors had to be resolved. These issues

have been largely overcome, and production processing runs smoothly most of the time, but work remains

to be done to improve the flexibility of the production

environment to efficiently handle the inevitable problems that arise.

2.2 DiFX Cluster Developments

The amount of storage space was greatly increased

over the last year with the addition of two new file

213
214 Titus et al.

servers and more disks for the compute cores. The >

142 TB of additional space has made it possible to

correlate more stations from files, to supplement the

Mark 5 playback units. This, along with the increased

number of stations sending their data via e-VLBI, allows experiments with a large number of stations to be

correlated in one pass. Another file server and a new

head node are due to be added to the cluster shortly.

2.3 DiFX Software Support

Support for the community continues for difx2mark4,

fourfit, and HOPS. This support includes addition of

features requested by users, other enhancements, and

bug fixes.

2.4 USNO GUI Installation

John Spitzak of USNO visited Haystack in December

to install the USNO GUI for setting up and running

experiments. The GUI was demonstrated to work in

our environment, which is the first time it had been installed outside of USNO.

2.5 DiFX-Mark IV Correlator Comparison

of Experiment RD1208

RD1208 was processed in its entirety on DiFX in as

nearly identical a way as possible to the Mark IV in order to use it for a comprehensive comparison. Analysis

of this data is pending.

2.6 Broadband Delay

Major broadband delay experiments were conducted

in January and May. In January the 24-hour “mixed

mode” RD1301 session was observed, with the GGAO

12-m and Westford antennas recording broadband data

and seven other IVS stations recording standard S/X

data at frequencies partially in common with the broadband. But further development of “zoom mode” in

DiFX is needed before the mixed wide/narrow band

data can be processed. In May broadband data were

recorded at GGAO and Westford over 24 hours primarily as a test of amplitude calibration. Processing

of the amplitude data for the May session is complete,

and work has begun to obtain geodetic results from the

data.

2.7 DBE Testing

Various DBE testing projects were conducted during

the year. Testing RDBE-H v1.4 vs. 1.5 firmware both in

the lab and between GGAO-Wf is one example. Testing of RDBE v3.0 with complex mode format has begun.

2.8 Mark 6

A Mark 6 playback unit was added to the DiFX cluster

late in the year. Zero-baseline data of various kinds

have been obtained from the RDBEs to test Mark 6

recording, playback, and correlation. VDIF format

fixes were initially needed in order to make correlation

of this recording format work.

2.9 Galactic Center Observations

Further u-VLBI observations of the Galactic Center

and other target sources, with dual polarization at most

sites, were recorded and correlated in 2013. These included three stations in addition to those participating

last year: APEX in Chile, Pico Veleta in Spain, and

Plateau de Bure in France. In July, fringes were found

to the LMT (Large MM Telescope), a new antenna in

Mexico. This antenna will be added to Event Horizon

Telescope (EHT) observations in the future.

2.10 2013 IVS TOW

For the IVS TOW meeting in May, the Haystack DiFX

cluster was used for a “practical correlation” class. A

IVS 2013 Annual Report
Haystack Correlator 215

small computer lab was set up to give students practice

in setting up an IVS experiment for correlation.

2.11 Support for Other Correlators

There were various projects to assist other correlators.

The USNO Mark IV experienced a failure of crate

two after some maintenance. This was diagnosed as a

FIFO chip failure and repaired. Support was provided

to Bonn for help with EHT co-processing of the March

observations. Help was provided to the Seshan group

so they could reproduce one of the DBE tests conducted in October 2012 at Haystack, in order for them

to validate their DiFX installation. Similar support was

given to the ASIAA group in Taiwan to assist them in

getting started with EHT project correlation on DiFX.

2.12 e-VLBI

Non-real-time transfers have continued. Data from 17

sessions were transferred to Haystack this year from

20 stations (eight in Japan, four in Western Europe,

four in Australia, two in South America, and two

in South Africa): Kashima34, Kashima11, Koganei,

Tsukuba, Chichijima, Ishigaki, Aira, Mizusawa, Onsala, Ny-Alesund, Wetzell, Noto, Hobart, Yarragadee,  ̊

Katherine, Warkworth, Fortaleza, Concepcion (via  ́

Bonn), Hart15M and HartRAO. The number and speed

of e-VLBI transfers increased significantly this year

after an upgrade to Haystack’s Internet connectivity in

2012 enabled data transfer rates up to 1.4 Gb/sec.

3 Experiments Correlated

In 2013, 31 geodetic VLBI sessions were processed,

at least in part, consisting of 15 R&Ds, five T2s, and

11 tests of various types. The test sessions included

the broadband sessions and fringe tests and an assortment of other projects, some of which were touched

on in the summary above. As usual, smaller tests were

not included in the above count because they were too

small to warrant individual experiment numbers. Routine production (i.e., not test experiments) was perfomed full time on the Mark IV at the beginning of the

year, then switched to the the DiFX correlator in July,

as noted previously.

4 Current/Future Hardware and

Capabilities

The Mark IV hardware correlator configuration described in last year’s report has been powered down.

The DiFX cluster currently consists of six PCs, each

with dual hex core 2.66 GHz Intel Xeon processors.

Two file storage servers, which can also act as DiFX

compute nodes, provide 120 TB of file storage. These

are all connected through a 40 Gb/sec infiniband

network fabric using a Qlogic switch. Currently six

Mark 5B playback units with DiFX fully installed are

connected to the infiniband fabric. We have processed

up to 19 stations in one pass with this setup through a

combination of playback units and files.

In 2014 we plan to add more storage, more compute

nodes, and a new head node, as currently one of the

compute nodes serves in the latter role.

5 Staff

5.1 Software Development Team

• John Ball - Mark 5A/5B; e-VLBI, retired in August

2013

• Roger Cappallo - HOPS post-processing software;

Mark 6 development; DiFX software development;

correlation trouble-shooting

• Geoff Crew - DiFX correlator development, postprocessing software; Mark 6

• Kevin Dudevoir - correlation; maintenance/support; Mark 5A/5B/5C; e-VLBI;

Linux conversion; correlator software and build

system development; computer system support/development; DiFX correlator development

• Jason SooHoo - e-VLBI; Mark 5A/5B/5C/6; computer system support

• Chester Ruszczyk - e-VLBI; Mark 5A/5B/5C/6

• Alan Whitney - system architecture; Mark

5A/5B/5C/6; e-VLBI

IVS 2013 Annual Report
216 Titus et al.

5.2 Operations Team

• Peter Bolis - correlator maintenance

• Alex Burns - playback drive maintenance; Mark

5 installation and maintenance; general technical

support

• Brian Corey - experiment correlation oversight; station evaluation; technique development

• Glenn Millson - correlator operator

• Arthur Niell - technique development

• Don Sousa - correlator operator; experiment setup;

tape library and shipping

• Mike Titus - correlator operations oversight; experiment setup; computer services; software and hardware testing

• Ken Wilson - correlator maintenance; playback

drive maintenance; general technical support

6 Conclusion/Outlook

Operational correlation at Haystack has fully migrated

to the DiFX software correlator. Enhancement of our

modest cluster is expected to continue in 2014 with the

addition of a dedicated head node and additional file

servers. Efforts to improve the production environment

will continue. Testing and full integration of Mark 6

recording systems and RDBE v3.0 into operations are

underway. More broadband observations, including the

addition of the Kokee 20-m antenna with a new broadband system, are anticipated.

IVS 2013 Annual Report
IAA Correlator Center 2013 Annual Report

Igor Surkis, Voytsekh Ken, Yana Kurdubova, Alexey Melnikov, Vladimir Mishin, Dmitry Pavlov, Nadezda Sokolova,

Violet Shantyr, Vladimir Zimovsky

Abstract The activities of the six-station IAA RAS

correlator include regular processing of national

geodetic VLBI programs Ru-E, Ru-U, and Ru-F. The

Ru-U sessions have been transferred in e-VLBI mode

and correlated in the IAA Correlator Center since

2011. In addition, the new FX correlator is being

designed.

1 General Information

The IAA Correlator Center is located at and staffed by

the Institute of Applied Astronomy in St.-Petersburg,

Russia.

The IAA Correlator Center is devoted to processing geodetic, astrometric, and astrophysical observations made with the Russian national VLBI network

Quasar.

2 Component Description

The ARC (Astrometric Radiointerferometric Correlator) (Figure 1) was the main data processing device in

the IAA Correlator Center in 2013. The ARC was designed and built in the IAA RAS from 2007 - 2009.

The correlator has XF design and is based on FPGA

technology.

The ARC is a six-station, 15-baseline correlator.

It is able to process up to 16 frequency channels on

Institute of Applied Astronomy RAS

IAA Correlator

IVS 2013 Annual Report

each baseline, for a total of 240 channels. The correlator accesses two-bit VLBI signals with 32 MHz maximal clock frequency. The maximal data range from

each station is 1 Gbit per second. The correlator requires VSI-H input VLBI signals, and it is equipped

with Mark 5B playback terminals.

Since 2011, the DiFX software correlator has been

used for some astrophysical experiments. DiFX is installed at the IAA on a Sun Fire X4450 Server as a

virtual machine under the VMware.

3 Staff

• Igor Surkis — leading investigator, software developer;

• Voytsekh Ken — GPU software developer;

• Alexey Melnikov — DiFX processing, scheduler of

the Ru-sessions;

• Vladimir Mishin — software developer, data processing;

• Nadezda Sokolova — software developer;

• Yana Kurdubova — software developer;

• Dmitry Pavlov — software developer;

• Violet Shantyr — software developer, post processing;

• Vladimir Zimovsky — leading data processing;

• Ekaterina Medvedeva — data processing;

• Alexander Salnikov — leading e-VLBI data transfer;

• Ilya Bezrukov — e-VLBI data transfer.

217
218 Surkis et al.

Fig. 1 View of the six-station ARC correlator, showing four racks containing (left to right) signal distribution and synchronization

system (SDSS) and three Mark 5B playback units, two correlator crates and KVM, three correlator crates, and one more cabinet with

SDSS and three Mark 5B playback units.

4 Current Status and Activities

4.1 Ru Sessions

The ARC correlator was used for processing all of the

national geodetic VLBI observations in the IAA Correlator Center in 2013. The Ru-E and Ru-U geodetic

VLBI sessions were carried out in IAA RAS.

The three-station, 24-hour EOP determination RuE sessions were carried out once per week, as in 2012.

The two-station, one-hour UT1-UTC determination

sessions in e-VLBI mode were carried out once per

day. The Ru-U sessions were executed with frequency

channel bandwidth 8 MHz and total bitrate 256 Mbps.

The data transfer speed from stations to correlator was

improved in 2012, and near to realtime correlation processing with data bitrate 256 Mbps was achieved.

4.2 DiFX Processing

In 2013, the DiFX software correlator continued to be

the main spectral line source processing tool. Target

sources are Orion KL, W49N, W3OH, and W75. It is

used to correlate data streams of 16-64 Mbps bitrate.

Output data resolution was up to 8,192 spectral channels which allows achievement of a frequency resolution of 0.25 kHz for W3OH in L-band. 41 Ru-P experiments were scheduled and observed in 2013, including

Crab nebula observations at L-band. Several experiments to monitor RFI were conducted. One experiment

with 2 Gbps bitrate and standard wideband geodetic

frequency mode and one experiment with 2 Gbps and

512 MHz bandwidth in X-band were done. The latter

experiment is planned to be processed in early 2014.

Three experiments were done with the Effelsberg radio telescope in collaboration with the Max Planck Institute for Radioastronomy. Data were transferred from

Bonn to Saint Petersburg using tsunami protocol at data

rates up to 400 Mbps. Medicina and Noto also joined

IVS 2013 Annual Report
IAA Correlator 2013 Report 219

one experiment and e-transferred data to Saint Petersburg directly from the stations to the Correlator Center. DiFX is installed on a GNU/Linux VMware virtual

machine on a Sun Fire X4450 Server. Test installation

on a new hybrid-blade cluster was done.

4.3 FX Correlator Design

The design of a new FX software correlator intended

for the new small antenna VLBI network was started

in 2012. The correlator design is supposed to process

data streams of up to 16 Gb/s from each observatory.

VLBI data are recorded from four frequency bands

with bandwidths of up to 1024 MHz in one circular polarization or up to 512 MHz in two linear polarizations

using 2-bit sampling. The input data format is VDIF.

The correlator computes cross-spectra with a resolution of up to 4,096 spectral channels and extracts up to

32 phase calibration tones in each frequency band of

each station.

In 2013, we elaborated the correlator’s structure

and developed the two-station software prototype.

“T-Platforms” company developed and mounted the

high-performance computing cluster at IAA (Figure 2). The software was installed and successfully

tested and benchmarked.

The main conception of the correlator comes from

the DiFX correlator, although it has several distinctive features. The most significant one is the usage of

graphical processing units (GPUs) for the main computations such as bit repacking, Fourier transformation,

doppler tracking, spectra multiplication, and phase cal

extraction.

The correlator equipment includes a data transfer

system based on fiber optic cable, power supply, conditioning system, and high performance compute cluster. The correlator’s hardware is based on hybrid blade

server technology. Each blade server contains two Intel

CPUs and two Nvidia Tesla GPUs. The present hardware of the one-baseline correlator’s prototype contains five blade servers made by “T-Platforms” company, which are inserted into chassis. The cluster also

includes power supply and power distribution units,

two cache servers, one head server, data storage with

capacity of 20 TB, an infiniband data commutator and

a fiber optic commutator. The cluster’s components are

mounted in a cabinet.

Fig. 2 View of the high-performance computing cluster based on

the hybrid blade servers.

The correlator’s topology consists of head, station,

and correlation software modules. The head module

controls all interblock processes and collects the results. Each station module processes data stream from

one station and provides phase calibration signal extraction, data synchronization, delay tracking, and bit

repacking. Each correlation module provides crossand autocorrelation spectra computing for all the stations.

Pcal extraction is realized using the method proposed by S. Pogrebenko. According to this method,

data are shifted by the offset frequency, so the phase

tones are in the equidistant frequency spacing. The

IVS 2013 Annual Report
220 Surkis et al.

shifted data are divided into frames with a size of doubled pcal tones, and then all the frames are summed. As

a result, white noise from the cosmic data is averaged

to zero, and only the phase tone information remains.

Then the FFT should be accomplished to get the pcal

data.

The cross-spectra computing algorithm is realized

in the following way. The received data blocks from

the station modules are copied to the GPU’s DRAM,

where unpacking of bits to single-precision numbers

and the fringe rotation are done. Then the FFT operation is completed, and finally the obtained data are

transferred to the spectra multipliers kernel, where they

are multiplied together and averaged within the chosen

time period. The output spectra are transferred to the

head module.

For six stations with data streams of 16 Gbps, these

algorithms require 76 Fermi GPUs for near real-time

processing.

5 Future Plans

The next two years will be devoted to development of

the cluster and software for the near-real time six station correlator. “T-Platforms” company will have developed and mounted a high-performance computing

cluster which will contain 40 blade servers by June,

2014.

IVS 2013 Annual Report
Correlation Processing in NICT Kashima

Mamoru Sekido, Kazuhiro Takefuji, Masanori Tsutsumi

Abstract Correlation processing of VLBI observation data has been performed by two sorts of software

correlation systems in NICT. One is the multi-channel

‘K5/VSSP software correlator’, and the other one is the

fast wideband correlator called ‘GICO3’. These correlators are used for processing of VLBI observations

conducted for R&D experiments. This paper reports

the activities of the correlation center in NICT.

1 General Information

Software correlator has become popular at recent VLBI

correlation centers. This trend was driven by the rapid

increase of processing capabilities of computer technologies and the increase of hard disk drive capacity.

VLBI group of NICT Kashima has played the leading

role in the development of operational software correlator from early 2000 [1, 2]. VLBI group of SpaceTime Standard Laboratory (STSL) of the National Institute of Information and Communications Technology (NICT) has been working on VLBI technology

development in collaboration with domestic institutes

and universities in the fields of geodesy, astronomy,

and space science. The current mission of our group

is precise frequency comparison between atomic standards at distant locations. In this development, VLBI

experiments have been conducted for research and development (R&D) purposes, and the data have been

processed by our own software correlation systems.

NICT Space-Time Standards Laboratory/Kashima Space Technology Center

NICT Correlator

IVS 2013 Annual Report

The correlation system is located in the Kashima Space

Technology Center (KSTC), although correlation processing is performed by sharing data with the network

file system (NFS) over the local area network (LAN)

spanning between the NICT headquarters in Tokyo and

KSTC.

Fig. 1 Location of the NICT-Koganei Headquarters and

Kashima.

2 Component Description

The correlation system is composed of high performance computer servers and a data recording system

with a RAID disk system. They are not always stored

in the same racks in the computer room but are located

separately and connected via 1000BASE-T network.

221
222 Sekido et al.

2.1 K5/VSSP Correlator

Conventional 16 channel geodetic VLBI observation

data is processed with the K5/VSSP software correlator, which was developed by T. Kondo [1]. A typical processing time for 256-Mbps (32-Mbps x 16-

channels) observations for the correlation of one baseline takes about two times the real observation scan

lengths when 16 cores of the servers A and B in Table 1 are used.

Table 1 CPU Servers used for correlation processing.

Servers CPU type and Core CPU clock Memory Size

A Intel Corei7 8 cores 3.0 GHz 16 GBytes

B Intel Corei7 8 cores 1.6 GHz 12 GBytes

C Xeon E5-2680 40 cores 1.2 GHz 66 GBytes

D Intel Corei7-3960X 12 cores 1.2GHz 66 GBytes

2.2 GICO3 Correlator

Fast wideband correlation software written by

M. Kimura [3] has been used with Giga-bit data acquisition system (ADS1000, ADS3000/ADS3000+). The

data acquired at 512-MHz or 1024-MHz bandwidth

(1024-Msps or 2048-Msps x 1 or 2-bit sampling =

1024-Mbps or 2048-Mbps) are processed with GICO3.

Correlation processing has been peformed with servers

C and D in Table 1. The processing time for 2-Gbps

mode (2048-Msps x 1-bit x 2-ch) for one baseline

(Kashima 34-m - Koganei 11-m) takes aproximately

five times the real data acquisition rate at present. Its

rate is thought to be limited by the 1-Gbps network

speed at the Koganei 11-m station.

2.3 Network Connection

The Kashima 34-m antenna site and the Kashima 11-m

station are connected via 10 Gbps LAN. The network

speed between the Kashima site and the Koganei 11-m

is currently 1 Gbps (Figure 2), but this will be upgraded

to 10 Gbps soon. The 10 Gbps network connection between KSTC and the NICT Koganei headquarters is

supported by research network JGN-X (Next GeneraJGN−X

Kashima

34m

11m

Kashima

Koganei

MARBLE2

Koganei 

11m

10Gbps 1Gbps

10Gbps

Fig. 2 Network speed between the Kashima and Konganei sites.

tion Network Test bed). For correlation processing of

the Kashima — Koganei baseline, the observation data

are not transferred before processing but are shared via

network file system (NFS) over the LAN. Therefore,

data processing can be started just after the observation. That is useful for a quick fringe check and a performance test.

3 Staff

Tsutsumi Masanori: In charge of maintenance of

data processing servers and data acquisition RAID

systems.

Takefuji Kazuhiro: Uses GICO3 correlator for R&D

VLBI experiments.

Sekido Mamoru: Uses K5/VSSP correlator for conventional VLBI observations and is in charge of

overall activities.

4 Current Status and Activities

The VLBI group of NICT Kashima has been conducting R&D VLBI observations for technology development. The current mission of our group is development

of a wideband VLBI observation system (named GalaV) for precise frequency comparison between newly

developed atomic standards. The Gala-V system employs similar radio frequency coverage (3-14 GHz)

with VGOS but acquires data of four 1 GHz bandwidth signals. Currently, R&D observing for the GalaV project has been performed with a single channel in

2013, and that data processing was performed with the

GICO3 software correlator.

IVS 2013 Annual Report
Correlation in Kashima 223

Fig. 3 Servers used for corelation processing.

5 Future Plans

The VLBI correlator NICT used was for R&D experiments conducted by NICT. Following the progress of

the Gala-V project, the load for data processing will increase. Therefore, increasing processing capacity and

more systematic configuration of the system are to be

considered.

Acknowledgements

We thank the research network JGN-X and the Information System Section of NICT for supporting the network environment for e-VLBI.

References

1. T. Kondo, et al., ‘Development of the new real-time VLBI

technique using the Internet Protocol’, IVS CRL-TDC News

No. 17, pp.22-24, 2000.

2. Hiro Osaki, Tetsuro Kondo, and Moritaka Kimura, ‘Development of Versatile Scientific Sampling Processor (VSSP)-

A Practical Approach’, IVS CRL-TDC News, No.20, pp.7-

9, 2002.

3. M. Kimura, and J. Nakajima, ‘The implementation of the PC

based Giga bit VLBI system’, IVS CRL-TDC News No.21,

pp.31-33, 2002.

IVS 2013 Annual Report
Shanghai VLBI Correlator 2013 Annual Report

Fengchun Shu, Weimin Zheng, Wu Jiang, Zhong Chen, Renjie Zhu

Abstract This report summarizes the activities of the

Shanghai VLBI Correlator during 2013. We have improved the delay model accuracy and real time processing capability. We also managed to develop an offline

software function to convert the correlator output into

FITS-IDI format. Furthermore, we obtained some experience in operating an ad hoc DiFX correlator and

HOPS software.

1 Introduction

The Shanghai VLBI Correlator is hosted and operated

by the Shanghai Astronomical Observatory, Chinese

Academy of Sciences. It is dedicated to the data processing of the Chinese domestic VLBI observing programs, inclusive of the CMONOC project for monitoring the Chinese regional crustal movement, and the

Chinese deep space exploration project for spacecraft

tracking.

As shown in Figure 1, the VLBI stations near

Shanghai, Kunming, and Urumqi participate in some

domestic geodetic sessions on an annual basis, while

the Beijing station is mainly used for spacecraft data

downlink and VLBI tracking. In 2013, we began

to process the VLBI data from the Shanghai 65-m

antenna, namely the Tianma Radio Telescope. A few

fringe tests with Chinese deep space stations Kashi

and Jiamus were also performed.

Shanghai Astronomical Observatory

Shanghai Correlator

IVS 2013 Annual Report

 75oE 90oE 105oE 120oE 135oE 

 16oN 

 24oN 

 32oN 

 40oN 

 48oN 

 56oN 

SHANGHAI

KUNMING

URUMQI

KASHI

BEIJING

JIAMUS

Fig. 1 Distribution of the VLBI stations in China.

2 Component Description

Based on the FX type VLBA correlator, we have been

designing two correlators since 2003. One is the hardware correlator using the FPGA technology. The other

one is the software correlator. The first version of our

software correlator has been operational since 2006

and was installed on AMD Opteron 2200 CPU computers and later on Intel X5400 CPU computers. Because

the software correlator was much easier to modify, we

adopted the second version of the software correlator for geodetic applications. By using Message Passing Interface (MPI) and the POSIX threads APIs, the

software correlator was migrated to a computer cluster

based on blade servers to get better performance since

2010. It was formally accepted as an IVS correlator in

March 2012.

In 2013, the Shanghai VLBI data processing center

was moved to the Sheshan area, just a few kilometers

from Tianma65 and Seshan25. A new hardware plat224
Shanghai Correlator 225

form was installed at the new VLBI center. Features of

the software correlator cluster are listed below.

• DELL M1000e Blade Server with 32 computing

nodes

• Computing node configuration: a two-socket Intel

E5-2640 CPU (2.5 GHz, six cores) with 24 GB of

memory

• Five I/O nodes with 264 TB raw storage capacity

• Two redundant administration nodes with BCM

cluster management software

• 40 G Infiniband for blade internal computing network connection

• 10 G Ethernet for blade internal and external data

network connection

A summary of the capabilities of the software correlator is presented in Table 1.

3 Staff

The people involved in the development and operation

of the Shanghai Correlator are listed below.

• Weimin Zheng: group head, software correlator

development

• Xiuzhong Zhang: CDAS and other technique development

• Fengchun Shu: scheduler, experiment oversight,

CDAS evaluation

• Zhong Chen: e-VLBI, cluster administration

• Weihua Wang: lead correlator operator, automatic

correlation process development

• Juan Zhang: correlator software development and

maintenance

• Yun Yu: operator, experiment support

• Wu Jiang: operator, experiment support

• Wenbin Wang: media library, computer services

• Renjie Zhu: CDAS development

• Zhijun Xu: FPGA programming, hardware correlator development

• Yajun Wu: FPGA programming

• Li Tong: postdoctor, correlator software development and maintenance

4 Summary of Activities

4.1 Correlator Software

In order to improve the accuracy of differential VLBI

observations to the level of better than 0.1 ns, we have

incorporated more corrections such as tidal station motion and gravitational delay in the correlator model.

We compared the time series of geometric delays with

those calculated by VieVS and DiFX-Calc. Our software results agree with DiFX-Calc at the level of 50 ps

and agree with VieVS better than 15 ps.

Great effort was made to shorten the data latency

for the navigation of spacecraft. For the navigation of

the Chang’E-3 lunar mission, we have improved the

realtime ability, and the total data turnaround time can

be shorter than one minute.

We also managed to develop an offline software

function to convert the correlator output into FITS-IDI

format. Thus we can make a comparison of correlation

results between our own correlator and DiFX in AIPS.

The average fringe phase difference for a two-minute

scan is about 0.1 degree.

4.2 Development of Hardware Correlator

We have built a new hardware correlator which has

performed well for the Chang’E-3 lunar mission. The

hardware correlator can perform real time correlation

at 128 Mbps per station. It includes five FPGA boards.

Each board has the same hardware, one Xilinx Virtex-4

FX60 and four LX160 FPGAs. A new hardware correlator based on Uniboard was also under design. It can

perform real time correlation at 2 Gbps per station for

a maximum of eight stations.

4.3 Performance of CDAS

The Chinese VLBI Data Acquisition System (CDAS)

is a type of digital backend designed to replace the traditional analog BBCs. The new digital system has better bandpass and wider bandwidth. In order to demonstrate the capability of CDAS, we used 1 Gbps (16 x

32 MHz, 1bit sampling, S/X) recording mode and deIVS 2013 Annual Report
226 Shu et al.

Table 1 Correlator capabilities.

Number available 5 Mark 5B

Playback speed 1.8 Gbps

Input data formats Mark 5B

Sampling 1 bit, 2 bits

IF channels ≤ 16

Bandwidth/channel (2, 4, 6, 8, 32) MHz

Spectral points/channel ≤ 65536

Geometric model supports plane wave front and curved wave front

online averaging time 0.1s∼4s

Phase Cal extraction yes

Output CVN matrix format, FITS-IDI format, or NGS card file

tected 18 weak sources at the level of 0.1 Jy with the

VLBI method for the first time.

In addition to the DDC version currently being

used, we are also developing a PFB version of CDAS

with much more compact design. It contains two Xilinx

K7 FPGAs for data processing. The input signals are

from two IFs with 512 MHz bandwidth each or one IF

with 1024 MHz bandwidth. Comparing with the previous platform which consists of four Xilinx V4 FPGAs,

the new one not only updated the key chips for DSP but

also added two TenGiga Ethernet SFP+ ports for data

transmission. For the application, the PFB version can

be configured with 32 MHz bandwidth x 16 channels

and 64 MHz bandwidth x 16 channels.

4.4 e-VLBI

The data link between the Shanghai VLBI center, Seshan25, and Tianma65 was upgraded to 10 Gbps. The

data link to other stations is 155 Mbps for domestic

e-VLBI observations. In the Chang’E-3 lunar mission,

the data transfer performed well at 64 Mbps for each

station.

4.5 DiFX Operation

We installed the DiFX 2.1 in an ad hoc 36 Intel X5650

(2.67 GHz) core cluster. With the help of the Bonn correlator and the GSFC group, we have obtained some

experience in using DiFX, HOPS, and DBedit to generate FITS-IDI data and Mark IV database files.

4.6 Experiments Correlated

In 2013, four domestic geodetic VLBI experiments

were carried out using 16 channels allocated at S/X

band, three experiments recorded at a data rate of

256 Mbps, and one at 1024 Mbps with a 32 MHz

bandwidth in each channel. After the Mark 5 modules

were shipped to the Shanghai VLBI center, the data

correlations were done by both the domestic correlator

and the DiFX correlator. The output of the DiFX correlator was further processed with HOPS. Meanwhile,

two milli-second pulsar astrometric observations

with the Chinese VLBI network were successfully

correlated with the DiFX correlator.

The differential VLBI observations continued to

support the navigation of the Chang’E-3 spacecraft

from the trans-lunar orbit to soft landing on the moon.

The DOR (Differential One-way Range) signals

transmitted from the spacecraft were received and

processed. Data processing was performed largely in

e-VLBI mode. The post-fit RMS delay residuals of

orbit determination were as good as 0.5 ns.

5 Future Plans

We will continue to support the data correlation of Chinese domestic VLBI observations and make comparisons of correlation results between our own correlator

and DiFX at different levels of data products. A hardware platform dedicated to DiFX correlation will be installed to meet the requirements of more astronomical

VLBI experiments and VGOS technique development

in China. We will also make some efforts to provide

service for international VLBI experiments.

IVS 2013 Annual Report
Tsukuba VLBI Correlator

Shinobu Kurihara 1, Tetsuya Hara 1,2

Abstract This report summarizes the activities of the

Tsukuba VLBI Correlator during 2013. The weekend

IVS Intensive (INT2) and the Japanese domestic VLBI

observations (JADE) were regularly processed using

the K5/VSSP correlation software.

1 Introduction

The Tsukuba VLBI Correlator, located in Tsukuba,

Japan, is hosted and operated by the Geospatial Information Authority of Japan (GSI). It is fully devoted to

processing geodetic VLBI observations of the International VLBI Service for Geodesy and Astrometry. All

of the weekend IVS Intensive (INT2) for UT1-UTC (=

dUT1) determination and the Japanese domestic VLBI

observations for geodesy called JADE organized by

GSI were processed at the Tsukuba VLBI Correlator.

The K5/VSSP correlation software developed by the

National Institute of Information and Communications

Technology (NICT) is used for all processing.

1. Geospatial Information Authority of Japan

2. Advanced Engineering Service Co., Ltd.

Tsukuba VLBI Correlator

IVS 2013 Annual Report

2 Component Description

2.1 e-VLBI

The Tsukuba VLBI Correlator has been connected

to a broadband network, and most of observed VLBI

data is delivered via the network. The Tsukuba VLBI

Correlator has a 10 Gbps dedicated link to the SINET4

operated by the National Institute of Informatics (NII),

which is connected to some research networks in

the world such as Internet2 in the U.S., GEANT2 in  ́

Europe, and TEIN4 at Singapore. It enabled us to

transfer massive amounts of data between the Tsukuba

VLBI Correlator and the overseas IVS Components.

The ultra-rapid EOP experiment (see Section 4.3) is

also performed by this network.

2.2 K5/VSSP Correlation Software

The K5/VSSP correlation software consists of several

programs for the calculation of a priori values of delay

and delay rate (apri calc), for the correlation processing for all observations (fx cor or cor), and for monitoring the results of the correlation processing by performing a so-called “coarse search” (sdelay), following several utilities [1]. Komb is a bandwidth synthesis software that was developed on an HP-1000 series minicomputer by using the FORTRAN program

language when the K-3 VLBI system was being developed. It has been ported to a Linux operating system by using the C language. All these programs were

developed and have been maintained by NICT. The

K5/VSSP correlation software can be used not only for

227
228 Kurihara and Hara

Fig. 1 Processing servers and Lustre File System at the Tsukuba VLBI Correlator.

K5 data processing but also for the Mark 5 data processing by using the data format conversion program

(m5tok5).

The following are processes of the K5 correlation

and programs used in each process.

1. Transferring data from network stations to the correlator (tsunami and tsunamid).

2. Data format conversion from Mark 5 to K5 (m5tok5

or m5btok5).

3. Preparation of a priori parameter files (apri calc).

4. Fringe search to find a clock offset at each pair of

stations (fx cor or cor).

5. Running correlation processing for all observations

(fx cor or cor).

6. Coarse search for estimating residual delay and delay rate, and plotting them on a 3-D diagram (sdelay).

7. Bandwidth synthesis to derive a multi-band delay (komb), and making Mark III databases by

MK3TOOLS to be submitted to the IVS Data

Center.

We developed several management programs to run

the above processes consecutively and ultra-rapidly.

The program for the management of data transfer

rapid transfer accesses the hosts in observing stations,

executes tsunamid there, and then at the correlator

side, executes tsunami to transfer data automatically

when an observation starts. The data is converted from

Mark 5 to K5 format by a program rapid conv as

necessary. Rapid cor is a program to search for fringes

of each baseline according to the clock information

of each station written in the FS log. Once the fringe

is detected, the main correlation processing is run

sequentially with the clock offset and rate found in the

fringe search until the last observation. Rapid komb

executes komb one after another for bandwidth synthesis process. The fully automated VLBI analysis

software c5++ developed by NICT can read the komb

output files directly and derives a VLBI solution [2].

2.3 Correlator Hardware Capabilities

The hardware supporting the activities of the Tsukuba

VLBI Correlator is summarized in Table 1. All these

pieces of equipment are general purpose and commerIVS 2013 Annual Report
Tsukuba Correlator 229

Fig. 2 New high performance servers and storage at the Tsukuba VLBI Correlator.

cially available products (Figure 1). It means that no

dedicated hardware is required in the K5 correlation

processing. In the correlator, mass data storage is required. Moreover, since some executed correlation processes access a data file simultaneously, the processing

capability of correlator depends on the Read I/O of the

data storage. The Lustre File System enables us to use

numerous HDDs mounted on a lot of servers like one

partition as if it were a large virtual disk. Thus, the I/O

performance is dramatically improved compared with

NFS.

Additionally, a set of high performance servers and

huge storage was newly installed (Figure 2). The new

system was originally purchased for the new VGOS

station Ishioka, but it can be used for operational correlation processing too. The specification of the new

system is also shown in Table 1. The new system can

shorten the time of correlation processing.

3 Staff

The technical staff at the Tsukuba VLBI Correlator are

• Shinobu Kurihara — correlator/analysis chief,

management.

• Tetsuya Hara (AES) — correlator/analysis operator, software development.

4 Correlator Operations

4.1 IVS Intensive for UT1-UTC

In 2013, 72 Intensive sessions in total were processed

at the Tsukuba Correlator. The details are described in

Table 2. In April, because the Kokee Park station antenna was repaired, the Intensives on weekdays were

done as INT2 sessions with the Tsukuba—Wettzell

baseline and processed at the Tsukuba Correlator. Just

after that, we found that there was a fatal flaw in the

pedestal of the track of the Tsukuba antenna. Since

then all Intensive sessions that included the Tsukuba

station were canceled, and Kokee was substituted for

Tsukuba in the Intensives on Sunday. Wettzell, NyIVS 2013 Annual Report
230 Kurihara and Hara

Table 1 Correlator Hardware Capabilities.

Current system New System

Number of servers 43 18

- 16 for correlation processing - 16 for correlation processing

- 1 for controlling correlation processing - 2 for controlling correlation processing

- 26 for data storage

Operating System CentOS version 5.3, 5.4 or 5.5 Red Hat Enterprise Linux 6.3

CPU Intel Xeon X3360 @2.83 GHz quad CPU Intel Xeon X5687 @3.60GHz quad CPU x 2

Intel Xeon 5160 @3.00 GHz dual CPU x 2

Intel Xeon X3480 @3.07 GHz quad CPU

Intel Xeon @3.80 GHz CPU x 2

Total storage capacity Lustre File System: 24.9 Tbytes Data Direct Networks storage: 513 Tbytes

Network 10 Gbps dedicated line connected to SINET4 by NII

Alesund, and Svetloe made a baseline with Kokee al-  ̊

ternatively.

The observed data at Wettzell is transferred to the

Tsukuba Correlator in real-time with the VDIF/SUDP

protocol and is recorded on a data storage device

in the K5 format directly. The observed data at the

Tsukuba station is also transferred to the correlator

immediately. Since the whole process from data

transfer through analysis is implemented by the rapid

programs (see Section 2.2), a dUT1 solution of the

Tsukuba—Wettzell baseline can be derived within

a few minutes after the end of the last scan of the

session. In the case of the Kokee baselines, because

the observed data at Kokee was transferred via the

U.S. Naval Observatory (USNO), it took a few hours

to derive a solution.

Table 2 Intensive sessions processed at Tsukuba Correlator.

Baseline Period # of sessions

Intensive 1 TsWz Apr 22 – Apr 30 7

Intensive 2 TsWz Jan 05 – Apr 28 34

KkWz May 12 – Jul 07 19

Oct 06 – Dec 29

KkNy Jul 14 – Jul 28 9

Aug 25 – Sep 29

KkSv Aug 04 – Aug 18 3

Total 72

4.2 JADE

JADE is the domestic geodetic VLBI series involving four GSI stations (Tsukuba, Aira, Chichijima, and

Shintotsukawa), three NICT stations (Kashima 34-m,

Kashima 11-m, and Koganei 11-m), and two VERA

stations of the National Astronomical Observatory of

Japan (NAOJ) located in Mizusawa and Ishigakijima.

Nine JADE sessions were correlated in 2013.

4.3 Ultra-Rapid EOP Experiment

This experiment is the joint project with Sweden, Australia, and South Africa having been continued since

2007. Several ultra-rapid EOP experiments were implemented and processed at Tsukuba Correlator. For

details refer to the report “Tsukuba VLBI Analysis

Center” in this volume.

5 Outlook

We will continue to process the IVS Intensive and

JADE correlation. For more stable operation, we will

make further improvements to the rapid programs and

start to use the new high performance servers and storage for our routine processing.

References

1. Kondo, T., et al.: Development of the K5/VSSP System, Journal of the Geodetic Society of Japan, 54(4), 233-248, 2008.

2. Hobiger, T., et al.: Fully automated VLBI analysis with c5++

for ultra-rapid determination of UT1, Earth Planets Space,

62, 933-937, 2010.

IVS 2013 Annual Report
Washington Correlator

David M Hall, Daniel Veillette

Abstract This report summarizes the activities of the

Washington Correlator for 2013. The Washington Correlator provides up to 80 hours of attended processing

per week plus up to 40 hours of unattended operation,

primarily supporting Earth Orientation and astrometric

observations. In 2013, the major programs supported

included the IVS-R4, IVS-INT01, APSG, and CRF observing sessions.

1 General Information

The Washington Correlator (WACO) is located at and

staffed by the U.S. Naval Observatory (USNO) in

Washington, DC, USA. The correlator is sponsored

and funded by the National Earth Orientation Service (NEOS), which is a joint effort of the USNO

and NASA. Dedicated to processing geodetic and

astrometric VLBI observations, the facility spent 100

percent of its time on these sessions. All of the weekly

IVS-R4 sessions, all of the IVS-INT01 Intensives,

and the APSG and CRF sessions were processed at

WACO. The facility houses a Mark IV Correlator and

the WACO DiFX correlator.

U. S. Naval Observatory

WACO Correlator

IVS 2013 Annual Report

2 Activities during the Past Year

The Washington Correlator continues to operate 80

hours per week with an operator on duty. The correlator has continued to function well unattended, allowing another 40 hours per week, on average, of extra

processing.

The correlator staff continues the testing and repair

of Mark 5 modules.

Intensive observations from Kokee Park and

Wettzell were routinely transferred via e-VLBI during

2013. 24-hour sessions from both Hobart antennas,

Katherine, Yarragadee, Warkworth, Ny-Alesund,  ̊

Fortaleza, Yebes, Noto, HartRAO, Wettzell, Tsukuba,

Aira, Kashima, Chichijima, and Sintotu were also

transferred by high-speed networks.

The USNO’s high speed Internet capability was upgraded to a full 1 GB/s in 2013.

Table 1 lists the experiments processed during

2013.

Table 1 Experiments processed during 2013.

Number of Sessions Type

49 IVS-R4 sessions

12 CRF (Celestial Reference Frame)

4 APSG

2 AUST

228 Intensives

231
232 Hall and Veillette

3 Staff

The Washington Correlator is under the management

and scientific direction of the Earth Orientation Department of the U.S. Naval Observatory.

Table 2 Staff.

Staff Duties

David Hall Chief VLBI Operations Division and

Correlator Project Scientist

Daniel Veillette VLBI Correlator Project Manager

Bruce Thornton Lead Physical Science Technician

Roxanne Inniss Media Librarian

Maria Davis Physical Science Technician

4 Future Plans

Transition to the DiFX Software correlator began near

the end of 2013 and should be completed by mid2014.

IVS 2013 Annual Report
Data Centers

BKG Data Center

Volkmar Thorandt, Reiner Wojdziak

Abstract This report summarizes the activities and

background information of the IVS Data Center for the

year 2013. Included are information about functions,

structure, technical equipment, and staff members of

the BKG Data Center.

1 BKG Data Center Functions

The BKG (Federal Agency for Cartography and

Geodesy) Data Center is one of the three IVS Primary

Data Centers. It archives all VLBI related data of

IVS components and provides public access for the

community. The BKG Data Center is connected to the

OPAR and GSFC CDDIS Data Centers by mirroring

the OPAR and the CDDIS file stocks several times per

day. The sketch in Figure 1 shows the principle of

mirroring:

IVS components can choose one of these Data Centers to put their data into the IVS network by using its

incoming area, which each Data Center has at its disposal. The BKG incoming area is protected, and users

need to obtain a username and password to get access.

An incoming script watches the incoming area and

checks the syntax of the files sent by IVS components.

If it is okay, the script moves the files into the Data

Center directories. Otherwise the files will be sent to a

badfile area. Furthermore, the incoming script informs

the responsible staff at the Data Center by sending emails about its activities. The incoming script is part

BKG

BKG Data Center

IVS 2013 Annual Report

Fig. 1 Principle of mirroring.

of the technological unit which is responsible for managing the IVS and the Operational Data Center, and

for carrying out the first analysis steps in an automatic

manner. All activities are monitored to guarantee data

consistency and to control all analysis steps from data

arrival to delivery of analysis products to IVS.

Public access to the BKG Data Center is available

through FTP and HTTP:

ftp://ivs.bkg.bund.de/pub/vlbi/

http://ivs.bkg.bund.de/vlbi/

235
236 Thorandt and Wojdziak

Structure of BKG IVS Data Center:

vlbi/ : root directory

ivs-special/ : special CRF investigations

ivscontrol/ : controlfiles for the data center

ivsdata/ : VLBI observation files

ivsdocuments/ : IVS documents

ivs-iers/ : old IERS solutions

ivsproducts/ : analysis products

crf/ : celestial frames

trf/ : terrestrial frames

eops/ : earth orientation (24h sessions)

eopi/ : earth orientation (Intensive sessions)

daily_sinex/ : daily sinex files (24h sessions)

int_sinex/ : daily sinex files (Intensive sessions)

trop/ : troposphere

2 Technical Equipment

The BKG IVS Data Center is based on a DELL Server

(SUSE Linux operating system), disk space of 500

GBytes (Raid system), and a backup system operated

by an automatic tape library.

3 Staff Members

Volkmar Thorandt (coordination, data analysis, data

center, volkmar.thorandt@bkg.bund.de)

Reiner Wojdziak (data center, Web design,

reiner.wojdziak@bkg.bund.de)

Dieter Ullrich (data analysis, data center, dieter.ullrich@bkg.bund.de)

Gerald Engelhardt (data analysis, gerald.engelhardt@

bkg.bund.de)

IVS 2013 Annual Report
CDDIS Data Center Summary for the IVS 2013 Annual Report

Carey Noll

Abstract This report summarizes activities during the

year 2013 and future plans of the Crustal Dynamics

Data Information System (CDDIS) with respect to the

International VLBI Service for Geodesy and Astrometry (IVS). Included in this report are background information about the CDDIS, the computer architecture,

staff supporting the system, archive contents, and future plans for the CDDIS within the IVS.

1 General Information

The Crustal Dynamics Data Information System (CDDIS) has supported the archiving and distribution of

Very Long Baseline Interferometry (VLBI) data since

its inception in 1982. The CDDIS is a central facility

providing users access to data and derived products to

facilitate scientific investigation. The CDDIS archive

of GNSS (GPS, GLONASS, etc.), laser ranging, VLBI,

and DORIS data are stored on-line for remote access.

Information about the system is available via the Web

at the URL http://cddis.gsfc.nasa.gov. In addition to the

IVS, the CDDIS actively supports other IAG services

including the International GNSS Service (IGS), the

International Laser Ranging Service (ILRS), the International DORIS Service (IDS), the International Earth

Rotation and Reference Frame Service (IERS), and the

Global Geodetic Observing System (GGOS). The current and future plans for the system’s support of the

IVS are discussed below.

NASA Goddard Space Flight Center

CDDIS Data Center

IVS 2013 Annual Report

2 System Description

The CDDIS archive of VLBI data and products is accessible to the public through anonymous ftp.

2.1 Computer Architecture

The CDDIS is operational on a dedicated server, cddis.gsfc.nasa.gov. The system has over 32 Tbytes of

on-line disk storage; at this time, over 180 Gbytes are

devoted to VLBI activities. The CDDIS is located at

NASA GSFC and is accessible to users 24 hours per

day, seven days per week.

3 Archive Content

The CDDIS has supported GSFC VLBI and IVS

archiving requirements since 1979.

The IVS Data Center content and structure is

shown in Table 1 (a figure illustrating the flow of information, data, and products between the various IVS

components was presented in the CDDIS submission

to the IVS 2000 Annual Report). In brief, dedicated

ftp-only accounts have been established on the CDDIS

incoming computer, cddisin.gsfc.nasa.gov. Using

specified filenames, Operation and Analysis Centers

deposit data files and analyzed results to appropriate

directories within their ftp-only accounts. Automated

archiving routines, developed by GSFC VLBI staff,

peruse the directories and move any new data to the appropriate public disk area. These routines migrate the

data based on the filename to the appropriate directory

237
238 Noll

as described in Table 1. Index files in the main subdirectories under ftp://cddis.gsfc.nasa.gov/pub/vlbi

are updated to reflect data archived in the filesystem.

Furthermore, mirroring software was installed on the

CDDIS host computer, as well as all other IVS Data

Centers, to facilitate equalization of data and product

holdings among these Data Centers. At this time,

mirroring is performed between the IVS Data Centers

located at the CDDIS, the Bundesamt fur Kartographie  ̈

und Geodasie in Leipzig, and the Observatoire de  ̈

Paris.

The public file system in Table 1 on the CDDIS

computer, accessible via anonymous ftp, consists of

a data area, which includes auxiliary files (e.g., experiment schedule information, session logs, etc.) and

VLBI data (in both database and NGS card image formats). A products disk area was also established to

house analysis products from the individual IVS Analysis Centers as well as the official combined IVS products. A documents disk area contains format, software,

and other descriptive files.

4 Data Access

During 2013, nearly 1,200 distinct hosts accessed the

CDDIS on a regular basis to retrieve VLBI related files.

These users, which include other IVS Data Centers,

successfully downloaded over 158 Gbytes of data and

products (1.2 M files) from the CDDIS VLBI archive

last year.

5 Future Plans

The CDDIS staff will continue to work closely with the

IVS Coordinating Center staff to ensure that our system is an active and successful participant in the IVS

archiving effort.

The CDDIS staff is currently assessing the system hardware architecture and near-term requirements.

Plans are to procure new server hardware in mid-2014

to expand on-line storage and ensure system reliability

for the next few years.

IVS 2013 Annual Report
CDDIS 2013 Report 239

Table 1 IVS Data and Product Directory Structure

Directory Description

Data Directories

vlbi/ivsdata/db/yyyy VLBI database files for year yyyy

vlbi/ivsdata/ngs/yyyy VLBI data files in NGS card image format for year yyyy

vlbi/ivsdata/aux/yyyy/ssssss Auxiliary files for year yyyy and session ssssss;

these files include: log files, wx files, cable files, schedule files, correlator notes

Product Directories

vlbi/ivsproducts/crf CRF solutions

vlbi/ivsproducts/eopi EOP-I solutions

vlbi/ivsproducts/eops EOP-S solutions

vlbi/ivsproducts/daily sinex Daily SINEX solutions

vlbi/ivsproducts/int sinex Intensive SINEX solutions

vlbi/ivsproducts/trf TRF solutions

vlbi/ivsproducts/trop Troposphere solutions

Project Directories

vlbi/ivs-iers IVS contributions to the IERS

vlbi/ivs-pilotbl IVS Analysis Center pilot project (baseline)

Other Directories

vlbi/ivscontrol IVS control files (master schedule, etc.)

vlbi/ivsdocuments IVS document files (solution descriptions, etc.)

vlbi/raw Raw VLBI data

vlbi/dserver dserver software and incoming files

IVS 2013 Annual Report
Italy INAF Data Center Report

Monia Negusini, Pierguido Sarti

Abstract This report summarizes the activities of the

Italian INAF VLBI Data Center. Our Data Center is

located in Bologna, Italy and belongs to the Institute of

Radioastronomy, which is part of the National Institute

of Astrophysics.

1 Introduction

The main analysis activity and storage is concentrated in Bologna, where we store and analyze single

databases, using CALC/SOLVE software.

The IRA started to store geodetic VLBI databases

in 1989, but the databases archived in Bologna mostly

contain data including European antennas from 1987

onward. In particular most of the databases available

here have VLBI data with at least three European stations. However we also store all the databases with the

Ny-Alesund antenna observations. In 2002 we decided  ̊

to store the complete set of databases available on the

IVS Data Centers, although we limited the time span

to the observations performed from 1999 onwards. All

the databases were processed and saved with the best

selection of parameters for the final arc solutions. In

order to perform global solutions, we have computed

and stored the superfiles for all the databases.

In some cases we have introduced GPS-derived wet

delays into the European databases (1998 and 1999

EUROPE experiments, for the time being), as if they

were produced by a WVR. These databases are availIstituto di Radioastronomia INAF, Bologna

INAF Data Center

IVS 2013 Annual Report

able and stored with a different code from the original

databases. In order to produce these databases, we have

modified DBCAL, and this new version is available to

external users.

2 Computer Availability and Routing

Access

To date, the main computer is a Linux workstation, on

which Mark 5 Calc/Solve version 10 was installed and

to which all VLBI data analysis was migrated. The Internet address of this computer is sarip.ira.inaf.it. Since

2011, a new server with a storage capacity of 5 TB

has been available, and, therefore, all experiments performed in the previous years were downloaded and

archived, thus completing the catalog. The older experiments will be analyzed in order to perform global

long term analysis. At present, the databases are stored

in the following directories:

1 = /data2/dbase2

2 = /geo1/dbase1

3 = /geo1/dbase

4 = /geo1/dbase3

The superfiles are stored in:

/data1/super1

The list of superfiles is stored in the file

/data2/mk5/save files/SUPCAT. The username for

accessing the databases is geo. The password

may be requested by sending an e-mail to negusini@ira.inaf.it.

240
Data Center at NICT

Ryuichi Ichikawa 1, Mamoru Sekido 2

Abstract The Data Center at the National Institute of

Information and Communications Technology (NICT)

archives and releases the databases and analysis results

processed at the Correlation Center and the Analysis

Center at NICT. Regular VLBI sessions of the Key

Stone Project VLBI Network were the primary objective of the Data Center. These regular sessions continued until the end of November 2001. In addition to the

Key Stone Project VLBI sessions, NICT has been conducting geodetic VLBI sessions for various purposes,

and these data are also archived and released by the

Data Center.

1 General Information

The IVS Data Center at National Institute of Information and Communications Technology (NICT) archives

and releases the databases and analysis results processed by the Correlation Center and the Analysis Center at NICT. Major parts of the data are from the Key

Stone Project (KSP) VLBI sessions [1], but other regional and international VLBI sessions conducted by

NICT are also archived and released. Since routine observations of the KSP network terminated at the end

of November 2001, there have been no additional data

from the KSP regular sessions since 2002.

On March 11th, 2011, the devastating megaquake

(Mw 9.0) hit our antennas. The azimuth track and one

1. National Institute of Information and Communications Technology (NICT)

2. Kashima Space Research Center, NICT

NICT Data Center

IVS 2013 Annual Report

azimuth wheel of the Kashima 34 m were damaged as

a consequence of the megaquake. The antenna repair

was finished in March 2013. On the other hand, the 11-

m antennas at Kashima and Koganei were not damaged

by the earthquake. We have carried out 20 VLBI experiments using the 11-m antennas including time and

frequency transfer experiments, international and domestic geodetic experiments, and astrophysical experiments.

The analysis results in SINEX (Solution INdependent EXchange) format as well as in other formats

are available on the WWW server. Database files of

non-KSP sessions, i.e. other domestic and international geodetic VLBI sessions, are also available on

the WWW server. Table 1 lists the WWW server

locations maintained by the NICT Data Center. In the

past, an FTP server was used to provide data files, but

it was decided to terminate the FTP service because of

the security risks of maintaining an anonymous FTP

server. Instead, the www3.nict.go.jp WWW server was

prepared to provide large size data files.

The responsibility for the maintenance of these

server machines was moved from the VLBI research

group in 2001 to a common division which handles all

institutional network service of the laboratory in order

to improve the network security of these systems.

2 Activities during the Past Year

2.1 KSP VLBI Sessions

The KSP VLBI sessions were performed with four

KSP IVS Network Stations at Kashima, Koganei,

Miura, and Tateyama on a daily or bi-daily basis

241
242 Ichikawa and Sekido

Table 1 URL of the WWW server systems.

Service URL

KSP WWW pages http://ksp.nict.go.jp/

IVS WWW mirror pages http://ivs.nict.go.jp/mirror/

Database files http://www3.nict.go.jp/aeri/sts/stmg/database/

e-VLBI Sessions http://www2.nict.go.jp/aeri/sts/stmg/research/e-VLBI/UT1/

until May 1999. The high-speed ATM (Asynchronous

Transfer Mode) network line to the Miura station

became unavailable in May 1999, and real-time

VLBI observations with the Miura station became

impossible. Thereafter, the real-time VLBI sessions

were performed with the three other stations. Once

every six days (every third session), the observed

data were recorded to the K4 data recorders at three

stations, and the Miura station participated in the

sessions with the tape-based VLBI technique. In this

case, the observed data at the three stations other than

the Miura station were processed in real-time, and

the analysis results were released promptly after the

observations completed. A day later, the observed

tapes were transported from the Kashima, Miura, and

Tateyama stations to the Koganei station for tape-based

correlation processing with all six baselines. After

the tape-based correlation processing was completed,

the data set produced with the real-time VLBI data

processing was replaced by the new data set.

In July 2000, unusual site motion of the Tateyama

station was detected from the KSP VLBI data series,

and the frequency of the sessions was increased from

bi-daily to daily on July 22, 2000. The daily sessions

were continued until November 11, 2000, and the site

motions of the Tateyama and Miura stations were monitored in detail. During the period, it was found that

Tateyama station moved about 5 cm to the northeast

direction. The Miura station also moved about 3 cm to

the north. The unusual site motions of these two stations gradually settled, and the current site velocities

seem to be almost the same as the site velocities before June 2000. The investigation into the time series

of the site positions shows that the unusual site motion started sometime between the end of June 2000

and the beginning of July 2000. At the same time, volcanic and seismic activities near the Miyakejima and

Kozushima Islands began. These activities are believed

to have caused the regional crustal deformation in the

area, explaining the unusual site motions at Tateyama

and Miura.

2.2 Other VLBI Sessions

In recent years, we have carried out time and frequency

transfer experiments using VLBI. In addition, domestic

and international geodetic and astronomical VLBI sessions were conducted by NICT in cooperation with the

Geospatial Information Authority of Japan (GSI), the

National Astronomical Observatory (NAO), and other

organizations. These sessions are listed in Table 2. The

recent observed data of these sessions were mainly processed by the K5 software correlator at NICT either at

Koganei or at Kashima or by using a real-time hardware correlator developed by NAO.

3 Current Status

The repair of the Kashima 34-m antenna was finished

in March 2013, and the antenna participated in various

experiments until now.

4 Future Plans

The IVS Data Center at NICT will continue its service and will archive and release the analysis results

accumulated by the Correlation Center and the Analysis Center at NICT. In addition, a number of VLBI

sessions will be conducted for the purposes of various

technology developments.

References

1. Special issue for the Key Stone Project, J. Commun. Res.

Lab., Vol. 46, No. 1, March 1999.

IVS 2013 Annual Report
Data Center at NICT 243

Table 2 VLBI sessions conducted by NICT (since 2005). In 2012, all experiments were carried out using the 11-m antennas at

Kashima and Koganei since the 34-m antenna was under repair to recover from the earthquake damage. At the end of March 2013,

the repair of the 34-m antenna was finished.

Year exp. names sessions

2005 Geodetic c0505 (CONT05, partial participation), GEX13

Hayabusa 14 sessions

2006 Geodetic GEX14, viepr2, CARAVAN (three sessions)

Spacecraft Geotail: one session

Pulsar one session

2007 Ultra Rapid e-VLBI 15 times, 29 sessions

Time Transfer four sessions, 12 days in total

Cs-Gas-Cell one session

Spacecraft Hayabusa: one session

2008 Ultra Rapid e-VLBI eight times, 33 sessions

Time Transfer 26 sessions

Variable Star e-VLBI 31 sessions

2009 e-VLBI 15 sessions, 90.5 hours in total

IVS 12 sessions, 332 hours in total

Time Transfer nine sessions, 72 hours in total

VERA 16 sessions, 149 hours in total

Survey 26 sessions, 276 hours in total

2010 IVS 38 sessions, 442 hours in total

Radio astronomy 34 sessions, 324 hours in total

Spacecraft (IKAROS, UNITEC-1, QZSS) 33 sessions, 259 hours in total

Domestic geodetic 13 sessions, 94 hours in total

Time Transfer nine sessions, 86 hours in total

e-VLBI nine sessions, 27 hours in total

2011 IVS two sessions, 48 hours in total

Radio astronomy 100 hours in total

earthquake damage investigation 216 hours in total

2012 IVS nine sessions, 216 hours in total

Radio astronomy (Sgr-A⋆) 13 sessions, 28 hours in total

Domestic geodetic three sessions, 72 hours in total

International fringe test (New Zealand and Korea) two sessions, 16 hours in total

International geodetic (New Zealand) one session, 24 hours in total

Time transfer 11 sessions, 264 hours in total

2013 IVS five sessions, 120 hours in total

Radio astronomy (including Sgr-A⋆ obs.) 71 sessions, 266 hours in total

Domestic geodetic 14 sessions, 213 hours in total

Time transfer two sessions, 46 hours in total

International fringe test (New Zealand and Korea) two sessions, 16 hours in total

Pulsar 39 session, 274 hours in total

IVS 2013 Annual Report
Paris Observatory (OPAR) Data Center

Christophe Barache, Sebastien Lambert

Abstract This report summarizes the OPAR Data Center activities in 2013. Included is information about

functions, architecture, status, future plans, and staff

members of OPAR data center.

1 General Information

The Paris Observatory (OPAR) has provided a Data

Center for the International VLBI Service for Geodesy

and Astrometry (IVS) since 1999. The OPAR as well as

CDDIS and BKG is one of the three IVS primary Data

Centers. Their activities are done in close collaboration

for collecting files (data and analysis files), and making them available to the community as soon as they

are submitted. The three Data Centers have a common

protocol and each of them:

• has the same directory structure (with the same control file),

• has the same script,

• is able to receive all IVS files (auxiliary, database,

products, and documents),

• mirrors the other ones every three hours, and

• gives free FTP access to the files.

This protocol gives the IVS community a transparent access to a Data Center through the same directory,

and a permanent access to files in case of a Data Center

breakdown.

Observatoire de Paris/SYRTE – CNRS – UMPC – GRGS

OPAR Data Center

IVS 2013 Annual Report

2 Architecture

To be able to put a file in a data center, operational and

analysis centers have to be registered by the IVS Coordinating Center. The file names have to conform to the

name conventions. A script checks the file and puts it

in the right directory. The script undergoes permanent

improvement and takes into account the IVS components’ requests. The structure of the IVS Data Centers

is detailed in Table 1.

3 Current Status

The OPAR Data Center is operated on a PC server

(PowerEdge 2800 - Xeron 3.0 GHz) located at the Paris

Observatory and running the Fedora Linux operating

system. To make all IVS products available on-line,

the disk storage capacity was significantly increased,

and the server is equipped now with a RAID 3 TB disk

extensible up to 4.7 TB.

The OPAR server is accessible 24 hours a day,

seven days per week through Internet connection with

2 Mbit/s rate. Users can get the IVS products by using

the FTP protocol. Access to this server is free for users.

FTP access: ftp ivsopar.obspm.fr

username : anonymous

password : your e-mail

cd vlbi (IVS directory)

This year, the OPAR successfully used the new mirroring method based on lftp. The OPAR Web statis244
OPAR Data Center 245

Table 1 Directories of the IVS Data Center.

RECENT used for the new mirroring method

ivscontrol control files needed by the Data Center (session code, station code, solution code...)

ivsdocuments documents about IVS products

ivsdata files related to the observations

aux auxiliary files (schedule, log...)

db observation files in database CALC format

ngs observation files in NGS format

sinex observation files in SINEX format

ivsproducts results from analysis centers

eopi Earth orientation parameters, Intensive sessions

eops Earth orientation parameters, 24-h sessions

crf celestial reference frames

trf terrestrial reference frames

daily sinex 24-hour time series solutions of Earth orientation and site positions in SINEX FORMAT

int sinex daily Intensive solution in SINEX format, mainly designed for combination

trop tropospheric time series (starting July 2003)

tics increased in 2013 — about 4,000 different visitors

reached the server in 2013. They viewed 33,500 pages

and downloaded three Go. The OPAR staff will continue to work with the IVS community and in close

collaboration with the two other primary Data Centers

in order to provide public access to all VLBI related

data. To obtain information about the OPAR Data Center please e-mail ivs.opa@obspm.fr.

IVS 2013 Annual Report

Analysis Centers

Analysis Center of Saint Petersburg University

Dmitriy Trofimov, Veniamin Vityazev

Abstract This report briefly summarizes the activities

of the Analysis Center of Saint Petersburg University

during 2013. The current status, as well as our future

plans, are described.

1 General Information

The Analysis Center of Saint Petersburg University

(SPU AC) was established in the Sobolev Astronomical Institute of the SPb University in 1998. The main

activity of the SPU AC for the International VLBI Service before 2007 consisted of routine processing of 24-

hour and one-hour observational sessions for obtaining

Earth Orientation Parameters (EOP) and rapid UT1-

UTC values, respectively. In 2008 we began submitting

the results of 24-hour session processing.

2 Activities during the Past Year

• In 2013, the routine estimation of the five Earth Orientation Parameters was performed. The OCCAM

software package (version 6 2) was used for current processing of VLBI data [1]. The time series

is named spu00004.eops. It includes data obtained

by the IRIS-A, NEOS-A, R1, R4, RDV, and R&D

observing programs, and it covers 25 years of observations (from January 2, 1989 until the end of

2013). The total number of experiments processed

Sobolev Astronomical Institute of Saint Petersburg University

AI SPbU Analysis Center

IVS 2013 Annual Report

at the SPU AC is about 1960, of which about 100

VLBI sessions were processed in 2013. Our experience and the equipment of the Analysis Center

was used for giving lectures and practical work on

the basics of radio interferometry to university students. We use our original manual on the training

in modern astrometry and in particular VLBI [2].

In 2013, the work of the SPU AC was performed

within the projects “Acquisition and analysis of

time-series in astronomy and study of astronomical catalogs” and “GLONASS, GPS and VLBI observations as the basis of astronomical, gravimetric,

and geodynamic studies” (SPU grants for fundamental research 6.0.161.2010 and 6.37.110.2011).

• All parameters were adjusted using the Kalman filter technique. For all stations (except the reference

station), the wet delay, clock offsets, clock rates,

and troposphere gradients were estimated. Troposphere wet delay and clock offsets were modeled

as a stochastic process such as a random walk. The

clock rates and the troposphere gradients were considered to be the constant parameters.

• The main details of the preparation of the EOP time

series spu00004.eops are summarized below:

– Data span: 1989.01–2013.12

– CRF: fixed to ICRF-Ext.2

– TRF: VTRF2005 was used as an a priori TRF

– Estimated parameters:

1. EOP: x, y,UT1−UTC,dψ,dε;

2. Troposphere: troposphere gradients were estimated as constant parameters, and wet troposphere delays were modeled as a random

walk process;

3. Station clocks were treated as follows: offset

as a random walk process, rate as a constant.

249
250 Trofimov and Vityazev

– nutation model: IAU 1980

– mapping function: VMF1

– technique: Kalman filter

– software: OCCAM v.6 2

3 Current Status

The assistant professor of Saint Petersburg University,

Dmitriy Trofimov, was in charge of the routine processing of the VLBI observations. General coordination and support for the activities of the SPU AC at

the Astronomical Institute was performed by Professor

Veniamin Vityazev.

4 Future Plans

In 2014, we are going to continue our regular processing of the VLBI sessions as well as giving lectures and

practical training for students in a special course on radio astrometry. This course is a part of the systematic

curriculum of astronomical education at SPb University.

References

1. O. Titov, V. Tesmer, J. Boehm. OCCAM v. 6. 0 Software

for VLBI Data Analysis, In International VLBI Service for

Geodesy and Astrometry 2004 General Meeting Proceedings, N. R. Vandenberg and K. D. Baver (eds.), NASA/CP2004-212255, pp. 267-271, 2004.

2. V. Vityazev, I. Guseva, V. Kiyaev, M. Mishchenko, O. Titov,

A. Tsvetkov. Celestial and Terrestrial Coordinates (In Russian), Manual on Astrometry, p. 301, SPb University, 2011.

IVS 2013 Annual Report
Geoscience Australia Analysis Center 2013 Annual Report

Oleg Titov

Abstract This report gives an overview of the activities of the Geoscience Australia IVS Analysis Center

during 2013.

1 General Information

The Geoscience Australia (GA) IVS Analysis Center

is located in Canberra within the National Geospatial

Reference System Section, Mineral and Natural Hazard Division (MNHD).

2 Activities during the Past Year

Several celestial reference frame (CRF) solutions have

been prepared using the OCCAM 6.2 software. The latest solution was uploaded in September 2013. VLBI

data consisting of 4,353 daily sessions from 25-Nov1979 to 03-September-2013 have been used to compute several global solutions with different sets of reference radio sources. This includes 5,927,370 observational delays from 2,950 radio sources having three or

more observations.

Station coordinates were also estimated using

No-Net-Rotation (NNR) and No-Net-Tranlation

(NNT) constraints. The long-term time series of the

station coordinates have been used to estimate the

corresponding velocities for each station. The tectonic

motion for the Gilcreek VLBI site after the Denali

Geoscience Australia

GA Analysis Center

IVS 2013 Annual Report

earthquake was modeled using an exponential function

typical of post-seismic deformation. The tectonic

motion of the Tigoconc (2010) and Tsukub32 (2011)

VLBI sites after recent strong earthquakes is currently

under study.

The adjustment was made by least squares collocation, which considers the clock offsets, wet troposphere

delays, and tropospheric gradients as stochastic parameters with a priori covariance functions. The gradient

covariance functions were estimated from GPS hourly

values.

Our first CRF solution, aus2013a.crf, was not imposed by the NNR constraints. The second CRF solution, aus2013b.crf, was imposed by NNR constraints.

This second solution is consistent with the CRF solutions submitted by other Analysis Centers.

In 2013, all three new AuScope 12-meter radio telescopes were actively working in different IVS geodetic

and astrometric programs. Two other Australian radio

telescopes – Hobart26, operated by the University of

Tasmania (UTAS), and Parkes, operated by the Australia Telescope National Facility (ATNF) — participated in the geodetic VLBI programs occasionally.

A program for optical identification and spectroscopy of the reference radio sources continued in

collaboration with the Australian Telescope National

Facility, University of Sydney and Nordic Optical

Telescope. A paper that includes redshifts of 126

reference radio sources has been published.

New observing runs at Gemini North, Gemini

South (service mode) and New Telescope Technology

(ESO) (visitor mode) were ongoing in 2013.

251
252 Titov

3 Staff Changes

Dr. Laura Stanford was actively involved in all the programs during the year and left this job in October 2013.

Acknowledgements

This report was published with the permission of the

CEO, Geoscience Australia.

IVS 2013 Annual Report
Report for 2013 from the Bordeaux IVS Analysis Center

Patrick Charlot, Antoine Bellanger, Romuald Bouffet, Geraldine Bourda, Arnaud Collioud, Alain Baudry  ́

Abstract This report summarizes the activities of the

Bordeaux IVS Analysis Center during the year 2013.

The work focused on (i) regular analysis of the IVSR1 and IVS-R4 sessions with the GINS software package, also extending our present solution back to 2002;

(ii) systematic VLBI imaging of the RDV sessions and

calculation of the corresponding source structure index and compactness values; (iii) investigation of the

correlation between astrometric position instabilities

and source structure variations; (iv) continuation of

our VLBI observational program to identify opticallybright radio sources suitable as transfer sources to align

the International Celestial Reference Frame (ICRF)

and the future Gaia frame; and (v) assessment of the

current IVS observing scheme for those Gaia transfer

sources comprised in ICRF2. Also to be mentioned is

the organization of a joint workshop with the Korean

Space Science Institute and participation in meetings

of the Working Group on the next ICRF realization.

1 General Information

The Laboratoire d’Astrophysique de Bordeaux (LAB),

formerly Bordeaux Observatory, is located in Floirac,

near Bordeaux, in the southwest of France. It is funded

by the University of Bordeaux and the Centre National

de la Recherche Scientifique (CNRS). VLBI activities

are primarily developed within the Metrologie de  ́

l’espace, Astrodynamique, Astrophysique (M2A) team.

Laboratoire d’Astrophysique de Bordeaux

Bordeaux Analysis Center

IVS 2013 Annual Report

The contribution of the Bordeaux group to the IVS

has been mostly concerned with the maintenance, extension, and improvement of the International Celestial

Reference Frame (ICRF). This includes regular imaging of the ICRF sources and evaluation of their astrometric suitability, as well as developing specific VLBI

observing programs for enhancing the celestial frame.

In addition, the group is in charge of the VLBI component in the multi-technique GINS software package [1] as part of a collaborative effort within the

French Groupe de Recherches de Geod  ́ esie Spatiale  ́

(GRGS) to combine VLBI and space geodetic data

(SLR, GPS, and DORIS) at the observation level. This

effort also involves institutes in Toulouse, Nice, and

Paris.

2 Description of Analysis Center

The Bordeaux IVS group routinely analyzes the

weekly IVS-R1 and IVS-R4 sessions with the GINS

software package. During the past year, weekly

normal equations for all such sessions in 2013 (with

six-hour EOP resolution) have been produced and

integrated in the multi-technique solutions derived by

the GRGS. We also worked at extending our solution

to the past, analyzing all IVS-R1 and IVS-R4 sessions

back to 2002. This extension was motivated by the

goal of producing test solutions combining all space

geodetic data at the observation level for the upcoming

ITRF2013.

The group is also focused on imaging the ICRF

sources on a regular basis by systematic analysis of the

data from the RDV sessions which are conducted six

times a year. This analysis is carried out with the AIPS

253
254 Charlot et al.

and DIFMAP software packages. The aim of such regular imaging is to characterize the astrometric suitability of the sources based on the so-called “structure index” and to compare source structural evolution and

positional instabilities. Such studies are essential for

identifying sources of high astrometric quality, which

is required, i.e., for the future Gaia link.

3 Scientific Staff

During the past year, there were no changes in the IVS

staff. In all, six individuals contributed to one or more

of our IVS analysis and research activities during 2013.

A description of what each person worked on, along

with the time spent on it, is given below.

• Patrick Charlot (20%): person with overall responsibility for Analysis Center work and data processing. His research interests include the ICRF densification, extension, and link to the Gaia frame, studies of radio source structure effects in astrometric

VLBI data, and astrophysical interpretation.

• Antoine Bellanger (100%): engineer with a background in statistics and computer science. He is

tasked to process VLBI data with GINS and to develop procedures and analysis tools to automate

such processing. He is also the M2A Web master.

• Romuald Bouffet (30%): Ph. D. student from University of Bordeaux whose thesis is focused on

the study of the relationship between radio source

structure and position instabilities. He is using astrometric data and VLBI images from IVS sessions.

• Geraldine Bourda (50%): astronomer in charge of  ́

developing the VLBI part of GINS and responsible for the analysis results derived from GINS. She

is also leading a VLBI observational program for

linking the ICRF and the future Gaia optical frame.

• Arnaud Collioud (100%): engineer with a background in astronomy and interferometry. His tasks

are to image the sources in the RDV sessions using

AIPS and DIFMAP, to develop the Bordeaux VLBI

Image Database and IVS Live tool, and to conduct

simulations for the next generation VLBI system.

• Alain Baudry (10%): radioastronomy expert with

specific interest in radio source imaging and astrometric VLBI. He is a Professor Emeritus and has

a part-time ESO contract to work on the ALMA

phasing for ultra-high resolution millimeter VLBI

science.

4 Analysis and Research Activities in 2013

As noted above, a major part of our activity consists

of imaging the sources observed during the RDV sessions on a systematic basis. During 2013, two such

sessions were processed (RDV90 and RDV92), resulting in 347 VLBI images at either X- or S-band for

161 different sources. The imaging work load has been

shared with USNO since 2007 (starting with RDV61);

the USNO group processes the odd-numbered RDV

sessions while the Bordeaux group processes the evennumbered ones. The VLBI images are used in a second

stage to derive structure correction maps, and visibility maps along with values for structure indices and

source compactness (see [2, 3] for a definition of these

quantities) in order to assess astrometric source quality. All such information is made available through the

Bordeaux VLBI Image Database (BVID)1. At present,

the BVID comprises a total of 3,691 VLBI images

for 1,126 different sources (with links to an additional

7,851 VLBI images from the Radio Reference Frame

Image Database of USNO) along with 11,542 structure

correction maps and as many visibility maps.

In addition to such regular imaging, studies aimed

at characterizing correlations between astrometric position instabilities and source structural variations were

pursued further. Moving from qualitative comparisons,

we calculated correlation coefficients between time series of source positions and brightness centroid motions (as derived from the available VLBI images) for

our previously selected set of 68 sources. Based on

this calculation, an overall positive correlation coefficient was found, indicating that on average source position instabilities and structural variations are linked [4].

However, the comparison also revealed that a fraction

of the sources show a negative correlation. Possible explanations for such discrepancies include misidentification of the core components over the epochs in the

successive VLBI maps and effects of the S-band data

which have not been considered in this work. Further

investigations are continuing through a careful exami1 The Bordeaux VLBI Image Database may be accessed at

http://www.obs.u-bordeaux1.fr/BVID.

IVS 2013 Annual Report
Bordeaux AC Report for 2013 255

nation of every individual source and assessment of the

significance of the calculated correlation coefficients.

Another major project carried within the group is

the identification and characterization of appropriate

radio sources to align the ICRF and the future Gaia

optical frame. To this end, two complementary directions are followed: (i) the identification of such sources

within ICRF2, and (ii) the search for additional sources

(outside of ICRF2) to increase the pool of transfer

sources. As noted in our 2012 IVS report, the examination of ICRF2 led to the identification of 195 transfer

sources. These were further characterized as 89 sources

which are sufficiently observed in current IVS programs (i.e., at least once a month), 62 sources which

are not observed well enough in these programs (i.e.,

less than once a month), 20 sources which have a

proper position accuracy but were only occasionally

observed, and 24 sources which have a poor position

accuracy, requiring further observations and improvement in accuracy to qualify as transfer sources. Following this analysis and previously proposed observations,

the IVS has now begun to insert some of these sources

into the regular IVS observing programs. The second

direction (i.e. searching for new sources) has led to the

identification of an additional 119 sources [5], all of

which were observed during a dedicated 72-hour astrometric VLBI session conducted with the combined

Very Long Baseline Array and European VLBI Network in May 2012. These data are now correlated

and are awaiting analysis. Also to be mentioned in

this framework is the extension of our work to the

southern hemisphere with the submission of a proposal

to the Australian Long Baseline Array (supplemented

with additional VLBI stations) to characterize potential

transfer sources in the south.

Most of this work (source imaging, assessment

of structural effects, identification of Gaia transfer

sources, etc.) naturally fits within the tasks of the

newly formed IAU Working Group on the next ICRF

realization which was set up at the 2012 IAU General

Assembly. As such, we contributed to the first two

meetings of this Working Group, held on 7 March

2013 in Espoo (Finland) and 18 September 2013 in

Paris.

5 Dissemination and Outreach

A joint VLBI astrometry workshop was organized

by the Bordeaux and KASI (Korean Astronomy

and Space Science) VLBI groups as part of bilateral agreements between France and Korea. The

workshop was held in Bordeaux on 24-25 October

2013. Sessions were devoted to radio interferometry

techniques, high-resolution astrometry, radio sources

and reference frames, as well as to time and frequency

standards. Dissemination activities also included a talk

given by P. Charlot at the Bureau des Longitudes in

Paris on 6 November 2013, highlighting recent VLBI

developments and the next generation VLBI system.

The IVS Live Web site [6], dedicated to monitoring IVS sessions and viewing VLBI images of the observed sources, was updated on a regular basis during 2013. It now includes 5,825 IVS sessions (with 68

stations participating) and 1,736 sources. Monitoring

of the connections indicates that there were 866 visits from around the world (40 countries, 286 locations)

during 2013, with 70% originating from different individuals. On the other hand, the Bordeaux VLBI Image

Database was accessed from 85 different locations in

33 countries. In all, there were 547 connections, with

one-third originating from different individuals.

6 Outlook

Our plans for the coming year are focused on moving

towards operational analysis of the IVS-R1 and IVSR4 sessions with the GINS software package. Imaging

of the RDV sessions and evaluation of the astrometric suitability of the sources will continue along the

same lines. On the observational side, the immediate

plan will be to analyze the astrometric data that we acquired on the 119 Gaia transfer sources identified from

our program (see Section 4). We also expect the IVS

to continue and expand observations of the 195 ICRF2

transfer sources now that Gaia has been launched and

is soon to begin operations. In this respect, it would

be desirable to schedule VLBI observations that are simultaneous with Gaia so that time series of radio and

optical positions can be compared on a detailed basis.

Depending on the outcome of our southern hemisphere

proposal, observations in the south should also begin

to develop. Finally, we expect to contribute to the work

IVS 2013 Annual Report
256 Charlot et al.

towards the next realization of the ICRF in line with

the plans that were set up during the initial meetings of

the IAU Working Group in charge of this task.

Acknowledgements

We would like to thank the Observatoire Aquitain des

Sciences de l’Univers (OASU) for supporting IVS activities in Bordeaux.

References

1. Bourda, G., Charlot, P., Biancale, R.: 2007, GINS: A New

Tool for VLBI Geodesy and Astrometry, 18th EVGA Working Meeting, Eds. J. Bohm, A. Pany, and H. Schuh, IGG  ̈

Vienna, p. 59–63.

2. Fey, A. L., Charlot, P.: 1997, VLBA Observations of Radio

Reference Frame Sources. II. Astrometric Suitability Based

on Observed Structure, ApJS, 111, pp.95–142.

3. Charlot, P.: 2008, Astrophysical Stability of Radio Sources

and Implication for the Realization of the Next ICRF, 5th

IVS General Meeting, St Petersburg, Eds. A. Finkelstein and

D. Behrend, p. 345–354.

4. Bouffet, R., Charlot, P., Lambert, S.: 2013, Correlation between source structure evolution and VLBI position instabilities, Proceedings of the 21st Meeting of the European

VLBI Group for Geodesy and Astrometry, Eds. N. Zubko

and M. Poutanen, Report of the Finnish Geodetic Institute,

p. 185–188.

5. Bourda, G., Collioud, A., Charlot, P., Porcas, R., Garrington, S.: 2012, Towards an Accurate Alignment of the VLBI

Frame and the Future Gaia Optical Frame: Global VLBI

Imaging Observations of a Sample of Candidate Sources

for this Alignment, IVS 2012 General Meeting Proceedings,

Eds. Dirk Behrend and Karen D. Baver, NASA/CP-2012-

217504, p. 334–338.

6. Collioud, A.: 2011, IVS Live: All IVS on your deskstop,

Proceedings of the 20th Meeting of the European VLBI

Group for Geodesy and Astronomy, Eds. W. Alef, S.

Bernhart, and A. Nothnagel, Universitat Bonn, Institut f  ̈ ur ̈

Geodasie und Geoinformation, Schriftenreihe 22, p. 14–18.  ̈

IVS 2013 Annual Report
BKG/DGFI Combination Center Annual Report 2013

Sabine Bachmann 1, Michael Losler  ̈

1

, Linda Messerschmitt 1, Ralf Schmid 2, Mathis Bloßfeld 2, Daniela Thaller 1

Abstract This report summarizes the activities of the

BKG/DGFI Combination Center in 2013 and outlines

the planned activities for 2014. The main focus in 2013

was on the inclusion of source positions in the combination process and the preparation for the IVS contribution to ITRF2013.

1 General Information

The BKG/DGFI Combination Center was established

in October 2008 as a joint effort of the Federal Agency

for Cartography and Geodesy (Bundesamt fur Kar-  ̈

tographie und Geodasie, or BKG) and the German  ̈

Geodetic Research Institute (Deutsches Geodatisches  ̈

Forschungsinstitut, or DGFI). The participating institutions, as well as the tasks and the structure of the

IVS Combination Center, are described in [1]. The

tasks comprise quality control and a timely combination of the session-based intermediate results of the

IVS Analysis Centers into a final combination product

(e.g., Earth orientation parameters, EOP). In coordination with the IVS Analysis Coordinator, the combination results are released as official IVS products. The

Combination Center is also expected to contribute to

the generation of the official IVS input to any ITRF

activities.

1. Federal Agency for Cartography and Geodesy (BKG), Frankfurt/Main, Germany

2. German Geodetic Research Institute (DGFI), Munich, Germany

BKG/DGFI Combination Center

IVS 2013 Annual Report

The BKG/DGFI Combination Center performs a

combination of session-based results of the IVS Analysis Centers on an operational basis. The strategy for

the combination is based on the combination of normal

equations and was adopted from the combination process as developed and performed by the IVS Analysis

Coordinator (cf. [2], [3]). At BKG, the following tasks

are performed:

• Quality control of the Analysis Center results:

checking the format of the results and their

suitability for combination, identification, and

reduction of outliers, comparison of the Analysis

Centers’ results with each other, and comparison

of the results with external time series provided by

IERS or IGS.

• Feedback to the Analysis Centers: quality control

results are available at the BKG IVS Combination

Center Web page [5].

• Generation of high-quality combination products

and timely archiving and distribution: combination

products are created by using the combination part

DOGS-CS of DGFI’s software package DOGS

(DGFI orbit and geodetic parameter estimation

software) [4].

• Submission of official IVS combination products to

the IERS: the products are submitted to the responsible IERS components to be used for IERS product

generation (e.g., EOP rapid products and the EOP

series IERS C04).

• Generation of the official IVS input to the ITRF: the

combined session products (from 1984 to present)

are submitted for ITRF computation in the form of

normal equations in SINEX format. This work is

also supported by the staff of the IERS Central Bureau, hosted by BKG.

257
258 Bachmann et al.

• Final results are archived in the BKG Data Center

and mirrored to the IVS Data Centers at Observatoire de Paris (OPAR) and Goddard Space Flight

Center (GSFC). This work is assisted by the staff

of the BKG Data Center in Leipzig.

The inclusion of new Analysis Centers has continued, a newly designed Web page was brought online,

and the Web-based analysis tools have been enhanced.

DGFI is in charge of the following Combination

Center functions:

• DGFI is developing state-of-the-art combination

procedures. This work, as well as the following

item, is also related to the ITRS Combination

Center at DGFI and DGFI’s efforts within the

IERS WG on Combination at the Observation

Level (COL).

• The software DOGS-CS is updated by implementing and documenting the developed state-of-the-art

combination procedures.

• Adhering to IERS Conventions: the DGFI DOGS

software package is continuously updated to be in

accordance with the IERS Conventions.

2 Activities During the Past Year

At BKG, the following activities were performed during 2013:

• Generation of a combined solution of IVS 24h rapid

sessions twice a week.

• Generation of a combined long-term (quarterly) solution of IVS 24h sessions every three months.

• Further development of the IVS Combination Center’s Web sites [5].

• Refinements of the combination procedure and implementation of source parameter combination.

• Development of an alternative combination procedure using the Bernese GNSS Software; implementation of the basic VLBI combination functions and

preprocessing routines in cooperation with the University of Bonn.

• Participation in a pilot project on digital object

identifiers (DOI) for data in cooperation with

R. Heinkelmann (Deutsches GeoForschungsZentrum, Germany); feasibility investigation for

providing data and meta data.

• A guideline for potential Analysis Centers that

intend to contribute to the combined solution

has been drafted in cooperation with R. Heinkelmann (GFZ). This guideline is available at

http://ccivs.bkg.bund.de/bid.

Figure 1 shows an example plot of the differences

in declination and right ascension for selected sources

between combined source positions and their ICRF2

position. The differences are in the range of ±0.4 mas.

0003−066 0014+813 0048−097 0059+581 0104−408 0106+013 0119+115 0133+476 0201+113 0235+164 0336−019 0458−020 0528+134 0537−441 0552+398 0556+238 0602+673

−1.2

−1

−0.8

−0.6

−0.4

−0.2

0

0.2

0.4

0.6

0.8

Di erences w.r.t. ICRF2 [mas]

Right Ascension

Declination

Fig. 1 Difference in right ascension (+) and declination (*) between combined and ICRF2 source positions.

At DGFI the following activities were performed

during 2013:

• Application of tidal corrections to UT1 according

to IERS Conventions (2010) by DOGS-CS.

• Development of an EOP routine to switch between

piecewise linear (offsets at 0h) and offset+drift representation.

• Improved realization of observation epochs in

DOGS-CS with 8-byte precision.

• Handling of radio source position parameters with

DOGS-CS.

2.1 Staff

The list of the staff members of the BKG/DGFI Combination Center in 2013 is given in Table 1.

Figure 2 shows the VLBI and IERS group at BKG

in Frankfurt. From left to right: Ole Roggenbuck (DFG

project on reference frames; combination at the observation level), Dr. Wolfgang Dick (IERS Central Bureau), Michael Losler (IVS combination; replaced by  ̈

IVS 2013 Annual Report
BKG/DGFI Report 2013 259

Table 1 Staff members of the BKG/DGFI Combination Center.

Name Affiliation Function E-Mail

Michael Gerstl DGFI Software maintenance gerstl@dgfi.badw.de

Ralf Schmid DGFI Combination strategies schmid@dgfi.badw.de

Mathis Bloßfeld DGFI Combination strategies blossfeld@dgfi.badw.de

Sabine Bachmann BKG Combination procedure development sabine.bachmann@bkg.bund.de

Linda Messerschmitt1 BKG Operational Combination /Web site maintenance linda.messerschmitt@bkg.bund.de

Michael Losler  ̈

2 BKG Operational Combination /Web site maintenance michael.loesler@bkg.bund.de

Linda Messerschmitt), Sabine Bachmann (IVS combination) and Dr. Daniela Thaller (head of section).

Fig. 2 IVS combination and IERS group at BKG in Frankfurt.

More details on the IVS Combination Center at

BKG can be found in an interview for the IVS Newsletter [6].

3 Current Status

In 2013, six IVS Analysis Centers (BKG, DGFI,

GSFC, IAA, OPA, and USNO) contributed to the

IVS combined product (see [5]). The rapid solutions

contain only R1 and R4 sessions, and new data points

are added twice a week as soon as the SINEX files

of at least four IVS Analysis Centers are available.

1 Linda Messerschmitt joined the BKG Combination Center in

October 2013.

2 Michael Losler left the BKG Combination Center in July 2013.  ̈

Long-term series are generated quarterly and include

every 24h session since 1984. The quarterly series

include long-term EOP, station positions, and velocities. Furthermore, a VLBI TRF is generated and

published. The preprocessing to read and write source

positions was implemented, and the software was

extended to process source parameters. The results

of the combination process are archived by the BKG

Data Center in Leipzig. The combined rapid EOP

series, as well as the results of the quality control of

the Analysis Center results, are also available directly

at the BKG/DGFI Combination Center Web page [5]

or via the IVS Analysis Coordinator Web site.

4 Future Plans

In 2014, the work of the BKG/DGFI Combination Center will focus on the following aspects:

• Generation of the IVS contribution to ITRF2013:

input data investigation, combination strategy and

evaluation of the combined EOP and station coordinate time series as well as the comparison of the

individual contributions of the Analysis Centers.

• Investigation into combination of source coordinates for time series of source coordinates and

generation of a combined celestial reference frame

based on VLBI intra-technique combination.

• Establish the digital object identifier (DOI) for

combined VLBI products in cooperation with

GFZ.

References

1. Schwegmann, W., Gerstl, M., Heinkelmann, R., BKG/DGFI

Combination Center Annual Report 2008, in: International

VLBI Service for Geodesy and Astrometry Annual Report

IVS 2013 Annual Report
260 Bachmann et al.

2008, NASA/TP-2009-214183, D. Behrend and K. D. Baver

(eds.), 250–252, 2009.

2. Nothnagel, A., Bockmann, S., Artz, T.,  ̈ Analysis Coordinator Report, in: International VLBI Service for Geodesy and

Astrometry 2007 Annual Report, NASA/TP-2008-214162,

D. Behrend and K. D. Baver (eds.), 16-17, 2008.

3. Nothnagel, A., Bockmann, S., Artz, T.,  ̈ Analysis Coordinator Report, in: International VLBI Service for Geodesy and

Astrometry Annual Report 2009, NASA/TP-2010-215860,

D. Behrend and K. D. Baver (eds.), 45–47, 2010.

4. http://ilrs.dgfi.badw.de/fileadmin/dogs/cs manual.ps

DOGS-CS software manual (German version only).

5. http://ccivs.bkg.bund.de/ BKG Combination Center Web

page.

6. Hase, H., BKG/DGFI Combination Center at Frankfurt, IVS

Newsletter 36, 2-3, 2013. http://ivscc.gsfc.nasa.gov/publications/newsletter/issue36.pdf.

IVS 2013 Annual Report
Matera CGS VLBI Analysis Center

Roberto Lanotte

Abstract This paper reports the VLBI data analysis

activities at the Space Geodesy Center (CGS) Matera,

from January 2013 through December 2013, and the

contributions that the CGS intends to provide for the

future as an IVS Analysis Center.

1 General Information

The Matera VLBI station became operational at the

Space Geodesy Center (CGS) of the Italian Space

Agency (ASI) in May 1990. Since then, it has been

active in the framework of the most important international programs. The CGS, operated by e-geos (a

Telespazio/ASI company) on behalf of ASI, provides

full scientific and operational support using the main

space geodetic techniques: VLBI, SLR, and GPS.

2 Activities during the Past Year

During 2013, the following activities were performed

at CGS:

• Global VLBI Solution cgs2013a

The main VLBI data analysis activities at the CGS

in the year 2013 were directed towards the realization of a global VLBI solution, named cgs2013a,

using the CALC/SOLVE software (developed at

Centro di Geodesia Spaziale (CGS) - e-geos SpA

CGS Analysis Center

IVS 2013 Annual Report

NASA/GSFC). The main and final characteristics

of this solution are:

– Data span:

1984.01.04 - 2012.12.27 (4356 sessions)

– Estimated Parameters:

· Celestial Frame: Right ascension and declination as global parameters for 845 sources,

· Terrestrial Frame: Coordinates and velocities for 81 stations as global parameters, and

· Earth Orientation: Unconstrained X pole, Y

pole, UT1, Xp rate, Yp rate, UT1 rate, dpsi,

and deps.

• IVS Tropospheric Products

Regular submission of tropospheric parameters

(wet and total zenith path delays, and east and

north horizontal gradients) for all VLBI stations

observing in the IVS R1 and R4 sessions continued

during 2013. Currently, 1,205 sessions have been

analyzed and submitted, covering the period from

2002 to 2013. The results are available at the IVS

products ftp site.

• CGS Contribution to IERS EOP Operational Series

Since 2008, CGS has been delivering IERS R1 and

R4 session EOP estimates as a regular contribution to the IERS EOP operational series. The whole

cgs2007a solution, available when the contribution

started, has been delivered to IERS as a reference

series updated by periodic EOP solution submissions.

261
262 Lanotte

2.1 Staff at CGS Contributing to the IVS

Analysis Center

• Dr. Giuseppe Bianco, responsible for CGS/ASI

(primary scientific/technical contact).

• Dr. Rosa Pacione, responsible for scientific activities, e-geos.

• Dr. Roberto Lanotte, geodynamics data analyst, egeos.

3 Future Plans

• Continue and improve the realization of our global

VLBI solution, providing its regular update on

time.

• Continue to participate in the IVS analysis projects.

• Start to contribute to the “Daily Solution Files

(DSNX)” project of the IVS, providing the

datum-free normal equations.

IVS 2013 Annual Report
DGFI Analysis Center Annual Report 2013

Ralf Schmid, Michael Gerstl, Manuela Seitz, Detlef Angermann

Abstract This report presents the activities of the

DGFI Analysis Center during 2013. Besides the

regular IVS submissions, DGFI started to reprocess

24-hour sessions including the estimation of source

positions. DOGS-RI, the new VLBI analysis software

to be used at DGFI, is near completion.

1 General Information and Component

Description

The DGFI Analysis Center (AC) is located at the German Geodetic Research Institute (Deutsches Geoda- ̈

tisches Forschungsinstitut, or DGFI) in the city center

of Munich in Germany. DGFI is an autonomous and independent research institution affiliated with the Bavarian Academy of Sciences and Humanities (BAdW) and

funded by the Free State of Bavaria.

Research performed at DGFI covers many different

fields of geodesy (geometric techniques, gravity field,

Earth system modeling, etc.) and includes the contribution to national and international scientific services

and research projects as well as various functions in

scientific organizations (see http://www.dgfi.badw.de).

DGFI closely cooperates with BAdW and the Technische Universitat M ̈ unchen (TUM, including person-  ̈

nel at the Geodetic Observatory Wettzell) within the

framework of the Center of Geodetic Earth System Research (CGE).

Deutsches Geodatisches Forschungsinstitut (DGFI)  ̈

DGFI Analysis Center

IVS 2013 Annual Report

DGFI has been acting as an IVS AC since the establishment of the IVS in 1999. Since November 2008,

DGFI has been an operational AC regularly submitting

constraint-free normal equations for 24-hour sessions

in the SINEX format. Since 2008, DGFI has also been

involved in the BKG/DGFI Combination Center.

2 Staff

In 2013, the DGFI AC had to cope with a rather low

number of personnel. After Robert Heinkelmann left

DGFI in autumn 2012 to become the head of the VLBI

group at the German Research Centre for Geosciences

(GFZ) in Potsdam, Julian Andres Mora-Diaz joined his

group in early 2013. And since spring 2013, Manuela

Seitz has been on maternity leave.

Table 1 Staff members and their main areas of activity.

Dr. Detlef Angermann Group leader

Dr. Michael Gerstl Development of the analysis

software DOGS-RI

Mr. Julian Andres Routine data analysis

Mora-Diaz (now at GFZ)

Dr. Ralf Schmid Routine data analysis, combination

of different space geodetic

techniques

Dr. Manuela Seitz CRF/TRF combination, ICRF3,

(currently on combination of different space

maternity leave) geodetic techniques

As all these vacancies could not be filled in the

meantime, the activities of the DGFI AC were more

or less limited to the routine analysis of 24-hour sessions which has been performed by Ralf Schmid since

263
264 Schmid et al.

the end of May 2013. In addition, Michael Gerstl is engaged in the development of a new VLBI analysis software called DOGS-RI (DGFI Orbit and Geodetic Parameter Estimation Software - Radio Interferometry).

Table 1 lists the staff members and their main areas

of activity.

3 Current Status and Activities

Analysis Activities

The DGFI AC tries to analyze all 24-hour sessions

for which a database file of at least version 4 is available using the VLBI analysis software OCCAM. Since

the end of 2012, source positions are among the estimated parameters contained in the normal equations

that are submitted to the IVS Combination Center. Before, source positions were fixed to their a priori values.

In June 2013, the handling of the cable calibration

data changed. Since then, the cable calibration of certain stations is turned off in case it degrades the solution. Before, the database settings were applied. Therefore, in the case of an extreme degradation, stations

sometimes had to be excluded from the solution.

At the same time, the DGFI AC started to reanalyze

sessions in the case in which recorrelated data considering additional stations become available. As recorrelated sessions are usually stored at the IVS Data Centers with the same name as the original database file,

updated sessions are not automatically detected. If a

recorrelation is announced via IVSmail, the download

is started manually.

In order to have consistent SINEX files, a reprocessing was started in autumn 2013 including the estimation of source positions, the proper handling of cable calibration data, and the consideration of recorrelated observation files. At the end of December 2013,

consistent DGFI normal equations were available from

July 2011 to December 2013.

If operational and reprocessed solutions are

summed up, in 2013 DGFI analyzed 325 sessions altogether from four different years (2008 and 2011-13)

and submitted the corresponding daily SINEX files

to IVS. Among them were 124 IVS-R1, 123 IVS-R4,

19 IVS-R&D, 15 CONT11, 11 EUROPE, ten VLBA,

eight IVS-T2, six IVS-OHIG, five CONT08, and

four APSG sessions (see Table 2).

Table 2 Sessions analyzed in 2013.

Session type 2008 2011 2012 2013 Total

APSG – 1 2 1 4

CONT08 5 – – – 5

CONT11 – 15 – – 15

EUROPE – 2 4 5 11

IVS-OHIG – 1 4 1 6

IVS-R1 – 24 52 48 124

IVS-R4 – 23 52 48 123

IVS-R&D – 3 9 7 19

IVS-T2 – 1 4 3 8

VLBA – 3 3 4 10

Total 5 73 130 117 325

Software Development

In order to follow IERS 2010 Conventions, OCCAM is

refined to become part of DOGS. The theoretical models for the group delay need time derivatives and, in

case of the delay rate, also the second time derivatives

of the input parameters. The former approach to approximate these derivatives by divided differences with

a fixed time step of two seconds was superseded.

Parameter and observation models were expanded

to provide analytically calculated first and second

time derivatives. This conversion is complete except

for some routines calculating the equinox-based

transformation matrix from the nutation parameters

∆ψ and ∆ε. Thus, only the branch based on XCIP,

YCIP, and the celestial intermediate origin is operative.

The correlations between (XCIP, YCIP) and (xpol, ypol)

are not yet theoretically modeled; condition equations

to prevent subdiurnal retrograde motions are missing.

4 Future Plans

In 2014, we would like to keep on reprocessing 24-hour

sessions backward from July 2011 besides our operational contributions to IVS. Apart from that, detailed

comparisons between DOGS-RI and OCCAM will be

necessary, before we can switch to the new software.

Acknowledgements

We would like to thank Robert Heinkelmann for his

continued support of the DGFI AC activities.

IVS 2013 Annual Report
GFZ Analysis Center 2013 Annual Report

Robert Heinkelmann 1, Maria Karbon 1, Li Liu 1,2, Cuixian Lu 1, Julian A. Mora-Diaz 1, Tobias J. Nilsson 1,

Virginia Raposo-Pulido 1,3, Benedikt Soja 1, Minghui Xu 1,2, Harald Schuh 1

Abstract This report briefly provides general information and a component description of the recently established IVS Analysis Center at GFZ and outlines the

planned activities.

1 General Information

Helmholtz Center Potsdam, GFZ German Research

Center for Geosciences is the national research center

for Earth sciences in Germany. The main tasks of GFZ

according to its website (www.gfz-potsdam.de) are:

System Earth—Research Focus of the GFZ German Research Center for Geosciences

The Earth is a dynamic planet. Under the influence of

external and internal forces, it is continuously changing.

The solid Earth, the atmosphere, the hydrosphere and the

things living within them are always interacting. In short,

the Earth is a complex system, with forces and interactions between many different partners. To understand the

world in which we live, from our regional environment

to the entire planet, it is necessary to understand how the

System Earth works in all details. In the analysis, we have

to include the activities of mankind and their influence on

the natural processes in this complex, nonlinear system,

which in turn affects the environment we live in.

The overarching research aim of the GFZ is one of developing strategies and demonstrating practical options,

e.g. to preserve natural resources and to exploit them in

1. Helmholtz Center Potsdam, GFZ German Research Center for

Geosciences

2. Shanghai Astronomical Observatory, Chinese Academy of

Sciences

3. Instituto Geografico Nacional, Centro Nacional de Infor-  ́

macion Geogr  ́ afica  ́

GFZ Analysis Center

IVS 2013 Annual Report

an environmentally friendly way, to guard against natural catastrophes, to assess changes in the climate and the

environment and man’s impact on these, and to research

and utilise our world below ground, all based on a comprehensive understanding of systems and processes.

At this research facility within Department 1

’Geodesy and Remote Sensing’ and its Section

1.1 ‘GPS/GALILEO Earth Observation,’ a VLBI

group was established in November 2012.

2 Component Description

Since December 2012, GFZ has been an associate

Analysis Center (AC) of IVS. We are installing and

automating our VLBI analysis process in preparation

for becoming an operational AC. We will analyze

all incoming geodetic/astrometric types of sessions

and provide interim results in the SINEX format

within 24 hours after the provision of database files

of version 4 or higher at IVS Data Centers. At the

end of 2013 we started a complete re-processing

of all available IVS databases to get prepared for a

contribution to ITRF2013. We are also performing as

an IVS Combination Center for tropospheric products.

In 2013 the IVS rapid combination product was

determined at GFZ, while results and written output

were still provided via the Deutsches Geodatisches  ̈

Forschungsinstitut (DGFI) webpage. In 2014, we

will finish the migration of the IVS troposphere

Combination Center from DGFI to GFZ.

265
266 Heinkelmann et al.

3 Staff

At the GFZ IVS AC, the operational work is done

by Robert Heinkelmann, Tobias Nilsson, and Julian

Mora-Diaz. In addition, Maria Karbon and Benedikt

Soja work within project VLBI-ART about the application of Kalman filtering to VLBI analysis, and Virginia Raposo-Pulido works on the ICRF and related

systematic effects. Liu Li and Minghui Xu are guest

PhD students from Shanghai, China, and Cuixian Lu is

a guest PhD student from Wuhan, China. Harald Schuh

is managing our group and, as long as his schedule allows, he is still very active for the IVS. A photo of us

is shown in Figure 1.

Fig. 1 The GFZ VLBI group in October 2013.

4 Current Status and Activities

• IVS Associate Analysis Center at GFZ

At GFZ we use VieVS for VLBI data analysis starting at DB version 4 or higher. Together with the

IVS Analysis Center at the Department of Geodesy

and Geoinformation, Vienna University of Technology, we develop VieVS.

• Space applications

Our scientific work focuses on VLBI applications

in space, on GNSS observations using VLBI antennas, and on co-location in space of the various

space geodetic techniques (VLBI, GNSS, SLR, and

DORIS). One of the next steps will be the development of the differential VLBI (D-VLBI) method

and its application for geodetic purposes.

• VLBI data analysis using Kalman filtering

Within the project VLBI-ART (VLBI Analysis in

Real-Time, [1]) we plan to implement a Kalman filter solution in the Vienna VLBI Sotware (VieVS)

[2], as an alternative to the classical least squares

solution (LSQ). The aim of the Kalman filter solution is that it should be able to analyze VLBI data

in near real-time. Thus, the software will be ready

for a possible future scenario where the VLBI observations are available with a much shorter latency

than today.

An advantage of a Kalman filter is that the parameters can be modeled as stochastic processes instead

of with the piece-wise linear parametrization normally used in the LSQ solution. This allows better

modeling of the random variations in e.g. the tropospheric delays. Furthermore, a Kalman filter requires less computer memory compared to the LSQ

method, what will be an advantage for VLBI2010

where the amount of data will increase by several

magnitudes. We will also investigate the possibility

of including data from other sensors in the Kalman

filter. These could for example be data on geophysical excitations of Earth rotations (e.g. from numerical weather prediction models), tropospheric delays

from water vapor radiometers or GNSS, or Earth

rotation parameters from GNSS and ring laser gyroscopes.

As a first step we have performed various investigations in which we applied Kalman filtering for

combining VLBI results (produced with the LSQ

solution in VieVS) with results from other techniques. For example we made several tests combining VLBI data with atmospheric excitations from

numerical weather prediction models. Furthermore,

we combined hourly EOP estimated from VLBI

and GNSS [3].

An interesting possibility is to use a Kalman filter

to combine UT1-UTC parameters estimated from

the VLBI Intensive sessions with Length of Day

(LOD) data obtained from GNSS [4]. The LOD

from GNSS provides precise information about the

short term (one week or less) UT1-UTC variations,

while the VLBI Intensives have the long-term stability. In addition, other parameters common to

both VLBI and GNSS can be combined in the

Kalman filter, i.e. polar motion, station coordinates,

IVS 2013 Annual Report
GFZ 2013 Report 267

and tropospheric delays. Because correlations between the VLBI UT1-UTC estimates and errors of

other parameters exist, this will additionally help to

improve the UT1-UTC results. As an example, Figure 2 shows UT1-UTC from 2008-2010 estimated

when also combining the tropospheric delays in the

Kalman filter, compared to when not doing this.

We found that the WRMS differences relative to

the UT1-UTC values estimated from normal IVSR1/R4 sessions slightly decreased from 27.1 μs to

26.1 μs.

2008 2008.5 2009 2009.5 2010 2010.5 2011

−200

−150

−100

−50

0

50

100

150

200

Year

 UT1−UTC [μs]

Kalman filter ERP

Kalman filter ERP+Trop

Fig. 2 UT1-UTC estimated from a Kalman filter combination

of the results of the VLBI Intensive sessions and the GNSS

LOD estimates, relative to estimates from the IVS-R1/R4 sessions. Shown are the results obtained when combining the UT1-

UTC/LOD and polar motion, as well as the case when also combining the tropospheric delay estimates.

• Long-term troposphere combined product

It is planned to generate a new updated version of

the long-term tropospheric combination product including the most recent observational data.

5 Future Plans

• IVS Operational Analysis Center at GFZ

At GFZ we would like to become an operational

Analysis Center of IVS. Therefore we are installing

and automating the standard VLBI data processing using VieVS in least squares estimation mode.

Once we have finished a complete re-processing of

all available IVS databases of version 4 or higher,

we will submit our solution to IVS, applying to become operational.

Acknowledgements

The VLBI-ART project is funded by the Austrian Science Fund (FWF), project number P24187-N21.

References

1. M. Karbon, T. Nilsson, C. Tierno Ros, R. Heinkelmann,

and H. Schuh. VLBI-Art: VLBI analysis in real-time. In

N. Zubko and M. Poutanen, editors, Proceedings 21th Meeting of the European VLBI Group for Geodesy and Astrometry, pages 95–97, Espoo, Finland, 2013.

2. J. Bohm, S. B  ̈ ohm, T. Nilsson, A. Pany, L. Plank, H. Spi-  ̈

cakova, K. Teke, and H. Schuh. The new Vienna VLBI software. In S. Kenyon, M. C. Pacino, and U. Marti, editors, IAG

Scientific Assembly 2009, number 136 in International Association of Geodesy Symposia, pages 1007–1011, Buenos

Aires, Argentina, 2012. Springer.

3. T. Nilsson, M. Karbon, and H. Schuh. A Kalman filter for

combining high frequency Earth rotation parameters from

VLBI and GNSS. In N. Zubko and M. Poutanen, editors,

Proceedings 21th Meeting of the European VLBI Group for

Geodesy and Astrometry, pages 117–120, Espoo, Finland,

2013.

4. T. Nilsson, M. Karbon, B. Soja, V. Raposo-Pulido,

R. Heinkelmann, J. Mora-Diaz, C. Lu, L. Liu, and H. Schuh.

Rapid UT1 estimation by combining VLBI Intensives with

GNSS. In Proceedings of the IAG Scientific Assembly, Potsdam, Germany, 2013. submitted.

IVS 2013 Annual Report
The BKG/IGGB VLBI Analysis Center

Volkmar Thorandt 1, Axel Nothnagel 2, Gerald Engelhardt 1, Dieter Ullrich 1, Thomas Artz 2, Sebastian Halsig2,

Andreas Iddink2, Judith Leek 2

Abstract In 2013, the activities of the BKG/IGGB

VLBI Analysis Center, as in previous years, consisted

of routine computations of Earth orientation parameter (EOP) time series and of a number of research topics in geodetic VLBI. The VLBI group at BKG continued its regular submissions of time series of tropospheric parameters and the generation of daily SINEX

(Solution INdependent EXchange format) files. Quarterly updated solutions were computed to produce terrestrial reference frame (TRF) and celestial reference

frame (CRF) realizations. The analysis of all Intensive

sessions for UT1–UTC estimation was continued. Additionally, the a priori pole coordinates were recorded

in the Intensive time series. The VLBI group at BKG

developed a procedure to get meteorological data from

a numerical weather model for stations with missing

meteorological data in the station log file. At IGGB,

the emphasis has been placed on individual research

topics.

1 General Information

The BKG/IGGB VLBI Analysis Center was established jointly by the analysis groups of the Federal

Agency for Cartography and Geodesy (BKG), Leipzig,

and the Institute of Geodesy and Geoinformation of

the University of Bonn (IGGB). Both institutions cooperate intensely in the field of geodetic VLBI. The responsibilities include both data analysis for generating

1. BKG

2. IGGB

BKG/IGGB Analysis Center

IVS 2013 Annual Report

IVS products and special investigations with the goal

of increasing accuracy and reliability. BKG is responsible for the computation of time series of EOP and

tropospheric parameters, for the generation of SINEX

files for 24-hour VLBI sessions and one-hour Intensive

sessions, and for the generation of quarterly updated

global solutions for TRF and CRF realizations. Besides

data analysis, the BKG group is also responsible for

writing schedules for the Int2 UT1-UTC observing sessions. Details of the research topics of IGGB are listed

in Section 3.

2 Data Analysis at BKG

At BKG, the Mark 5 VLBI data analysis software system Calc/Solve, release 2010.05.21 [1], has been used

for VLBI data processing. It is running on a Linux operating system. As in the previous releases, the Vienna

Mapping Function (VMF1) has been implemented in a

separate Solve version. This modified version was used

for all data analysis. The VMF1 data were downloaded

daily from the server of the Vienna University of Technology. Additionally, the technological software environment for Calc/Solve was refined to link the Data

Center management with the pre- and post-interactive

parts of the EOP series production and to monitor all

Analysis and Data Center activities.

• Processing of correlator output

The BKG group continued the generation of calibrated databases for the sessions correlated at the

MPIfR/BKG Astro/Geo Correlator at Bonn (e.g.,

EURO, OHIG, and T2) and submitted them to the

IVS Data Centers.

268
BKG/IGGB VLBI Analysis Center 269

• Scheduling

BKG continued scheduling the Int2 Intensive

sessions, which are observed on the TSUKUBAWETTZELL baseline. Altogether, 41 schedule

files for this baseline were created in 2013. Due

to maintenance combined with the shutdown

of the TSUKUBA antenna from the middle of

2013, 22 schedule files for baseline KOKEEWETTZELL, nine schedule files for baseline

KOKEE-NYALESUND, and three schedule files  ̊

for baseline KOKEE-SVETLOE were also made

available.

• BKG EOP time series

The BKG EOP time series bkg00013 was continued. The main features of this solution were

not changed. But the station coordinates of three

VLBI sites in Australia (HOBART12, KATH12M,

and YARRA12M) and one site in New Zealand

(WARK12M) were estimated as global parameters

because of an observation period of up to three

years for each station. Furthermore the fact of unavailable meteorological data in station log files

could be compensated by the use of meteorological data from European Centre for Medium-Range

Weather Forecasts (ECMWF) contained in VMF1

data files. This procedure was integrated into the

technological process of EOP series generation.

Each time after the preprocessing of any new

VLBI session (correlator output database version

1), a new global solution with 24-hour sessions

since 1984 was computed, and the EOP time

series bkg00013 was extracted. Altogether, 4,540

sessions were processed. The main parameter

types in this solution are globally estimated station

coordinates and velocities together with radio

source positions. The datum definition was realized

by applying no-net-rotation and no-net-translation

conditions for 25 selected station positions and

velocities with respect to VTRF2008a and a

no-net-rotation condition for 295 defining sources

with respect to ICRF2. The station coordinates of

the telescopes AIRA (Japan), CHICHI10 (Japan),

CTVASTJ (Canada), DSS13 (USA), HART15M

(South Africa), KASHIM34 (Japan), KOGANEI

(Japan), PT REYES (USA), SEST (Chile), SINTOTU3 (Japan), TIGOCONC (Chile), TSUKUB32

(Japan), UCHINOUR (Japan), WIDE85 3 (USA),

VERAISGK (Japan), VERAMZSW (Japan), and

YEBES40M (Spain) were estimated as local

parameters in each session.

• BKG UT1 Intensive time series

Regular analysis of the UT1-UTC Intensive time

series bkgint09 was continued. Moreover, reporting was extended to also list the a priori pole coordinates in each session. The series bkgint09 was

generated with fixed TRF (VTRF2008a) and fixed

ICRF2. The a priori EOP were taken from final

USNO series [2]. The estimated parameter types

were only UT1-TAI, station clock, and zenith troposphere.

The algorithms of the semi-automatic process for

handling the Intensive sessions Int2/3 with station

TSUKUBA after the Japan earthquake [3] was

further used; i.e. before the regular analysis can

be started, the most probable station positions of

TSUKUBA for the epochs of the Int2/3 sessions

have to be estimated.

A total of 4,584 UT1 Intensive sessions were analyzed for the period from 1999.01.01 to 2013.12.31.

• Quarterly updated solutions for submission to

IVS

In 2013 one quarterly updated solution was computed for the IVS products TRF and CRF. There

are no differences in the solution strategy compared to the continuously computed EOP time series bkg00013. The results of the radio source positions were submitted to IVS in IERS format. The

TRF solution is available in SINEX format, version

2.1, and includes station coordinates, station velocities, and radio source coordinates together with the

covariance matrix, information about constraints,

and the decomposed normal matrix and vector.

• Tropospheric parameters

The VLBI group of BKG continued regular submissions of long time series of tropospheric parameters to the IVS (wet and total zenith delays and

horizontal gradients) for all VLBI sessions since

1984. The tropospheric parameters were extracted

from the standard global solution bkg00013 and

transformed into SINEX format.

• Daily SINEX files

The VLBI group of BKG also continued regular

submissions of daily SINEX files for all available

24-hour sessions for the IVS combined products

and for the IVS time series of baseline lengths. In

addition to the global solutions, independent session solutions were computed for the station coorIVS 2013 Annual Report
270 Thorandt et al.

dinates, radio source coordinates, and EOP parameters including the X,Y-nutation parameters. The a

priori datum for TRF is defined by the VTRF2008a,

and ICRF2 is used for the a priori CRF information.

• SINEX files for Intensive sessions

The parameter types are station coordinates, pole

coordinates and their rates, and UT1-TAI and

its rate. But only the normal equations stored in

the SINEX files are important for further intratechnique combination or combination with other

space geodetic techniques.

3 Research Topics at IGGB

• Delay correction model for gravitational deformations of the Effelsberg radio telescope

After having carried out and analyzed terrestrial

laser scanner observations of the main reflector of

the Effelsberg 100-m radio telescope, we have embarked on the construction of a full delay correction

model for the gravitation deformations. The main

effect is a bending of the support beam which holds

the vertex of the paraboloid. The second largest effect is a variation of the position of the sub-reflector

along the line of sight. With only a small impact, the

variations in the focal length enter the path length

variations. At the same time, the illumination function has to be taken into account and serves as a

weighting function for the path lengths depending

on the distance of the rays from the optical axis.

The total effect would range from zero to -100 mm

if observations at zero and 90 degrees elevation

are compared. The complete delay model for Effelsberg was prepared for publication in Journal of

Geodesy.

• Development of an automatic scheduling procedure

The automatic scheduling method developed

at IGGB has been extended by useful steering

parameters to create flexible observing plans. The

simulation tool for assessment and evaluation

was further developed and improved. Various

observing scenarios of Intensives including twin

radio telescopes were examined and compared with

one other. Furthermore, the software has been extended to schedule typical 24-hour multi-baseline

sessions. An additional option to use artificial

satellites as possible sources was implemented.

Finally, the question of whether a cluster analysis

of observed source positions can be used to classify

and compare different VLBI observing plans has

been investigated [4].

• Studies on VLBI observations of satellites

The observation of artificial Earth orbiting satellites with VLBI telescopes is one of the major challenges in the near future. In initial studies, this

was addressed at IGGB. Starting with considerations about the signals’ characteristics and necessary adaptations of the correlator model, scheduling of VLBI sessions including satellite observations have been performed. The scheduling was

performed with the NASA/GSFC scheduling package SKED [5] as well as the IGGB scheduling approach mentioned above. For the scheduled observations, clock noise, and atmospheric noise as well

as baseline dependent noise terms were added to

generate realistic observations [6]. Finally, geodetic parameters as well as simplistic orbit parameters were estimated by using the VLBI Time Delay

library [7].

• Application of inequality constraints

Refractivity variations in the neutral atmosphere

contribute considerably to the error budget of

VLBI. Generally, the tropospheric delay parameters are divided into two components; the

hydrostatic a priori information is taken into account by applying an adequate model whereas the

wet delay is estimated within the VLBI analysis.

Sometimes, the standard VLBI analysis leads to

negative tropospheric parameters, which do not

reflect actual meteorological and physical conditions. For this purpose, an Inequality Constrained

Least Squares adjustment from the field of convex

optimization has been used to constrain these

parameters to non-negative values. This methodology has been applied to VLBI data analysis to

improve the parameter estimation. However, as

the hydrostatic a priori information is not always

perfect, the approach is currently not applicable on

a routine basis.

• Modification of the stochastic model

Besides long periodic variations, micro-scale phenomena also affect geodetic observations and therefore the tropospheric parameters. Such turbulent

processes can be best described stochastically using the widely accepted Kolmogorov turbulence

IVS 2013 Annual Report
BKG/IGGB VLBI Analysis Center 271

theory. However, the correlations between observations are generally not considered in the standard

VLBI analysis, leading to deficiencies in modeling the stochastic properties of the observations. In

order to receive a more reliable stochastic model,

the additional stochastic properties are now incorporated into the VLBI analysis. That means that the

standard variance-covariance matrix is enhanced by

the additional stochastic information derived from

different turbulence models.

• Determination of a combination approach to derive the next generation of the ICRF

The currently existing realizations of the International Celestial Reference System (ICRS), the International Celestial Reference Frame 1 (ICRF1)

and ICRF2, are based on solutions estimated by a

single VLBI group. In contrast, the International

Terrestrial Reference Frame (ITRF) is based on

a multi-technique combination with contributions

from different geodetic space techniques. Furthermore, these individual technique-specific solutions

are generated in an intra-technique combination. To

overcome the shortcomings of the past ICRF determination, one of the main goals for the upcoming realizations of the ICRS and ITRS is an entirely consistent and simultaneous computation of

both frames. This includes inter- as well as intratechnique combinations. Focusing on consistency

between different VLBI solutions is the first necessary step before passing on to multiple space techniques. For this purpose, a concept for the generation of a VLBI intra-combined CRF was developed. This includes the identification of the requirements, difficulties, and individual steps of the

intra-technique combination procedure. Based on

the knowledge that has been gained, the combination software BonnSolutionCombination (BoSC)

has been gradually developed. This software supports the combination on the level of normal equation systems and contains several special analysis and settings features. These features will become indispensable for any upcoming CRF investigations dealing with combinations. Preliminary results confirm the proper functioning of the combination procedure and the corresponding software

developed at the IGG.

4 Personnel

Table 1 Personnel at BKG/IGGB Analysis Center

Thomas Artz IGGB +49-228-733563 artz@igg.uni-bonn.de

Gerald Engelhardt BKG +49-341-5634438 gerald.engelhardt@bkg.bund.de

Sebastian Halsig IGGB +49-228-732623 halsig@igg.uni-bonn.de

Andreas Iddink IGGB +49-228-732623 iddink@igg.uni-bonn.de

Judith Leek IGGB +49-228-733565 judith.leek@igg.uni-bonn.de

Axel Nothnagel IGGB +49-228-733574 nothnagel@uni-bonn.de

Volkmar Thorandt BKG +49-341-5634285 volkmar.thorandt@bkg.bund.de

Dieter Ullrich BKG +49-341-5634328 dieter.ullrich@bkg.bund.de

Reiner Wojdziak BKG +49-341-5634286 reiner.wojdziak@bkg.bund.de

References

1. GSFC, NASA (2010): Release of Mark 5 VLBI Analysis

Software Calc/Solve from May 21, 2010 (Web reference:

http://gemini.gsfc.nasa.gov/solve).

2. USNO (2013): Earth orientation parameters series from finals USNO series 2013, (Web reference:

http://gemini.gsfc.nasa.gov/500/oper/solve apriori files/usno

finals.erp).

3. Engelhardt G., Thorandt V., Ullrich D. (2013): Rapid UT1

Estimation Derived from Tsukuba VLBI Measurements after 2011 Earthquake. In: Proceedings of the 21st Meeting

of the European VLBI Group for Geodesy and Astronomy

2013, edited by N. Zubko and M. Poutanen, pages 85-87,

Kirkkonummi 2013, Finland.

4. Leek J., Artz T., Nothnagel A.. (2013): Assessment of VLBI

Intensive Schedules by Means of Cluster Analysis. In: Proceedings of the 21st Meeting of the European VLBI Group

for Geodesy and Astronomy 2013, edited by N. Zubko and

M. Poutanen, pages 211-215, Kirkkonummi 2013, Finland.

5. J. Gipson (2012): GSFC VLBI SKED

Software Package,(Web reference:

http://lupus.gsfc.nasa.gov/software sked.htm), 2012.

6. Artz T., Nothnagel A., La Porta, L. (2013): VLBI Observations of Geostationary Satellites. In: Proceedings of the 21st

Meeting of the European VLBI Group for Geodesy and Astronomy 2013, edited by N. Zubko and M. Poutanen, pages

217-221, Kirkkonummi 2013, Finland.

7. Petrov L. (2013): Library VTD for computation of VLBI

time delay from October 10, 2013 (Web reference:

http://astrogeo.org/vtd).

IVS 2013 Annual Report
GSFC VLBI Analysis Center Report

David Gordon 2, Chopo Ma 1, Dan MacMillan 2, John Gipson 2, Sergei Bolotin 2, Karine Le Bail 2, Karen Baver 2

Abstract This report presents the activities of the

GSFC VLBI Analysis Center during 2013. The GSFC

VLBI Analysis Center analyzes all IVS sessions,

makes regular IVS submissions of data and analysis products, and performs research and software

development aimed at improving the VLBI technique.

1 Introduction

The GSFC VLBI Analysis Center is located at NASA’s

Goddard Space Flight Center in Greenbelt, Maryland.

It is part of a larger VLBI group which also includes

the IVS Coordinating Center, the CORE Operation

Center, a Technology Development Center, and a

Network Station. The Analysis Center participates in

all phases of geodetic and astrometric VLBI analysis,

software development and research. We maintain a

Web site at http://lupus.gsfc.nasa.gov. We provide a

pressure loading service to the geodetic community

at http://gemini.gsfc.nasa.gov/results/aplo and a new

ray tracing service. We provide additional services

for hydrology loading, nontidal ocean loading, and

meteorological data. These services can be found by

following the links on the GSFC VLBI group Web

site: http://lupus.gsfc.nasa.gov/dataresults main.htm.

1. NASA Goddard Space Flight Center

2. NVI, Inc./NASA Goddard Space Flight Center

GSFC Analysis Center

IVS 2013 Annual Report

2 Analysis Activities

The GSFC VLBI Analysis Center analyzes all IVS

sessions using the Calc/Solve and νSolve systems,

and performs the fourfit fringing and Calc/Solve

analysis of the VLBA-correlated RDV sessions. The

group submits the analyzed databases to IVS for all

R1, RDV, R&D, APSG, AUST, INT01 and INT03

sessions. During 2013, GSFC analyzed 163 24-hour

sessions (52 R1, 50 R4, six RDV, ten R&D, five AUST,

three APSG, seven EURO, five T2, five OHIG, eight

CRF, five CRDS, and seven JADE) and 333 one-hour

UT1 sessions (243 INT01, 53 INT02, and 37 INT03),

and we submitted updated EOP and daily Sinex files

to IVS immediately following analysis.

3 Research Activities

• Intensive (IVS-INT01) Scheduling: We continued

to study the Uniform Sky Strategy (USS), an alternative INT01 scheduling strategy proposed and

tested in 2009/2010 and used for the INT01s on

alternating days since mid-2010. We focused on

refining the USS to address ways in which it underperforms the original scheduling strategy. We

investigated the effects of schedule characteristics

(e.g., temporal distribution of the observations) on

schedule metrics (e.g., protection against random

noise). We also investigated changing the schedule characteristics, and in turn the metric values, by

passing new parameter values to program sked.

• Source Monitoring: Together with USNO we

continued monitoring all ICRF2 defining sources

and all good geodetic sources, and this year we

272
GSFC Analysis Center 273

added the Gaia transfer sources. The goal is to

observe all geodetic and Gaia transfer sources

12 times/year and the remaining ICRF2 defining

sources five times/year. The R1, R4, and RDV

sessions participate in the source monitoring

program.

• Good Geodetic Source Catalog: Good geodetic

sources are scarce. In 2011, many were removed

because of time variability of their positions

(special handling sources). In 2013, there were 266

geodetic sources in the good geodetic catalog. To

search for additional sources, we used an approach

similar to that described by Jing Sun (Shanghai

Astronomical Observatory) in her PhD thesis.

Our criteria was as follows: a structure index (SI)

less than or equal to 2.5 (701 sources in IERS

Technical Note No 35, Table 1) and an X-band flux

greater than 0.25 Jy (658 sources in flux.cat). Of

the 152 sources meeting both criteria, 105 were

already in the good list and 47 were not. We wrote

a proposal to observe these 47 sources in R&D

sessions to verify if they could be detected and

to measure their fluxes. They were observed in

RD1302, RD1303, and RD1304. After analysis, 35

were found to be suitable and were added to the

good geodetic source catalog.

• Gaia Transfer Sources: In preparation for linking

the future ICRF3 and Gaia optical reference

frames, four lists of transfer sources (quasars that

should be visible by both systems) were compiled

by Observatory of Bordeaux personnel. Class

4, with 24 sources, had the weakest and least

observed sources. We scheduled these 24 sources

in R&D and RDV sessions. Some were detected

in the R&Ds, and all were detected in the RDVs.

Their fluxes were added to the sked flux catalog.

These will be re-observed occasionally in future

R&D and/or RDV sessions.

• Thermal Deformation Modeling: Thermal expansion can affect a VLBI antenna’s height by as much

as 20 mm. In Le Bail et al. (2013), we investigated

the impact of thermal expansion, as well as the optimal time lags for steel telescope structures and concrete foundations, using the Nothnagel model (J.

Geodesy, 83, pages 787–792, 2009). We compared

different solutions of the R1 and R4 sessions from

January 2002 to March 2011 with and without the

thermal expansion model and with different time

lags. Thermal deformation modeling significantly

improved the VLBI solutions, improving the baseline length repeatability on more than 75% of the

baselines by more than 1 mm on average, and reducing the WRMS per station. The time lag for the

steel structures was optimal when set to zero, one,

or two hours. However, for concrete foundations,

no sensitivity to time lag was found. We believe

this is because the concrete foundations are much

smaller than the steel structures. Also, preliminary

results show significant correlations between 1) the

maximum WRMS improvement and the height of

the foundation, 2) the maximum WRMS improvement and the distance from the movable axis to the

antenna vertex, and 3) the optimal time lag for the

antenna and the antenna diameter.

• Nutation Analysis: We rehabilitated nutkal2012.f, a

Fortran routine that uses the Kalman filter to regularize the nutation time series. The model is defined

by a linear trend and specified harmonics, and the

program includes an indicator of the quality of the

estimate (goodness of fit).

• Analysis of LOD Time Series with the SSA: Variations in the temporal length-of-day (LOD) contain

information on phenomena related to the continuous evolution of Earth processes: tidal energy dissipation and core-mantle coupling (decadal and secular) and meteorological and solar-lunar tide effects

(annual and semiannual). We studied an LOD time

series obtained from VLBI and extracted its principal components using Singular Spectrum Analysis

(SSA) (Le Bail et al., 2014). After removing the

long-term trend which explains 73.8% of the signal, three remaining components explain a further

22.0% of the signal: an annual and a semi-annual

signal as well as a second trend. Using the complex demodulation method, we obtained the variations in the amplitudes of the annual and semiannual components. We compared the Multivariate

ENSO index (MEI) with these series and with the

second trend obtained by the SSA. The correlations

are significant: 0.58 for the annual component, -

0.48 for the semi-annual component and 0.46 for

the second trend.

• Troposphere Raytracing: We wrote a paper on the

calculation of troposphere raytrace delays and the

application of raytraced delay corrections. It will be

submitted to the Journal of Geophysical Research.

These delays were calculated by raytracing 3D refractivity fields computed from the NASA/GSFC

IVS 2013 Annual Report
274 Gordon et al.

GEOS 5.9.1 numerical weather model. Repeatabilities were reduced for 70% of CONT11 baseline

lengths and for 84% of CONT11 vertical site coordinates. We set up a raytracing service that provides

raytrace delays for all VLBI sessions since 2000 at

http://lacerta.gsfc.nasa.gov/tropodelays.

• Hydrology Loading: We wrote a paper on hydrology loading entitled, “Continental hydrology loading observed by VLBI measurements”, which was

submitted to Journal of Geodesy. It discusses the

VLBI analysis results due to applying a hydrology

loading series calculated from either 1) the GSFC

GLDAS hydrology model or 2) GRACE (Gravity

Recovery and Climate Experiment) mascons. We

obtained a reduction in 1) baseline length repeatabilities for 80% of baselines, 2) site vertical repeatabilities for 80% of the sites, and 3) annual site

vertical amplitudes for 90% of the sites.

• Space Geodesy Project Simulations: We are working with Erricos Pavlis (UMBC) to optimize the

choice of a global network of co-located technique

sites and specifically to decide where NASA

should establish new sites. We have provided the

VLBI observations and solution setup input for

Geodyn SLR+VLBI+GPS combination solutions.

Simulated observed VLBI delays consist of troposphere turbulence, clock, and observation noise

contributions. We have done simulations of current

observing networks of legacy antennas and are

working on the simulations for future networks of

broadband antennas, which are expected to grow to

15-20 antennas by around 2018.

• Second Epoch VCS Observations: A proposal to reobserve up to 2400 VCS (VLBA Calibrator Survey)

sources was submitted to the VLBA and approved.

The investigators are D. Gordon (PI), C. Ma, six

other IVS members and two NRAO astronomers.

This project was granted eight 24-hour sessions and

will use the RDBE system at X- and S-bands with

16 32-MHz channels. The observations will run in

2014.

4 Software Development

The GSFC VLBI Analysis Center develops and

maintains the Calc/Solve analysis system, a package

of ∼120 programs and 1.2 million lines of code.

During 2013, modifications were made to enable

Calc/Solve to be compiled, loaded, and run on 64-bit

machines. Additional modifications to allow it to be

compiled with gfortran, instead of the Intel compiler,

are underway.

Program calc was updated to version 11 for compliance with the IERS 2010 Conventions. Calc11 uses

the IAU2006/2000 Precession/Nutation model, a new

ocean loading model (Hardisp) with 342 constituent

tides, an ocean pole tide loading model, and improved

high frequency EOP corrections. We also began work

on a specialized version, dcalc, for use with the difx

software correlator. Dcalc also contains a near-field

delay model, based on the model of Sekido and Fukishima (J. Geodesy, 80, pages 137–149, 2006), to allow better correlation of Earth satellites and planetary

probes.

We continued development of the νSolve analysis

program. The vgosDB part of the I/O module was improved and redesigned. Also, essential parts of the software were optimized to improve performance. Numerous comparisons of interactive Solve and νSolve have

shown the two to be comparable. νSolve is now the

standard tool for processing the IVS-R4 and IVS-INT

sessions at GSFC.

We continued to develop and refine the vgosDB

data format to store VLBI data. This year we concentrated on programs to reproduce all stages of the processing of Mark III databases. vgosDBmake takes correlator output and knits the files together into the new

format. vgosDBcalc is analogous to calc in that it adds

theoretical and partials to the vgosDB session. vgosDBcal reads the log files and adds cable cal and met

data. Since νSolve can read the vgosDB format, we are

now able to perform all stages of analysis starting with

correlator output. We also developed the utilities vgosDBview to view and modify data in this format, and

vgosDBcompare which will compare files in the new

format and find the differences.

It is well known that the scatter of baseline length is

larger than it should be, based on the formal errors of

the Solve solutions. One possible explanation for this

is the presence of unmodeled station dependent noise.

We developed software to determine this noise. The

software takes as input baseline length measurements

from some set of sessions, for example CONT11. It

then adds station-dependent-noise to the formal errors

until the chi-square of the baseline scatter is approximately equal to 1.

IVS 2013 Annual Report
GSFC Analysis Center 275

Table 1 Staff members and their main areas of activity.

Ms. Karen Baver Intensive analysis, monitoring, and improvement; software development; Web site development;

quarterly nuvel updates.

Dr. Sergei Bolotin Database analysis, νSolve development, ICRF3.

Dr. John Gipson Source monitoring, high frequency EOP, parameter estimation, new data structure, station dependent noise.

Dr. David Gordon Database analysis, RDV analysis, ICRF3, astronomical source catalogs, calc/dcalc development,

quarterly ITRF updates.

Dr. Karine Le Bail Time series statistical analysis (EOP, nutation, source positions), database meteorological data

analysis.

Dr. Chopo Ma ICRF3, CRF/TRF/EOP, VGOS development.

Dr. Daniel MacMillan CRF/TRF/EOP, mass loading, antenna deformation, VGOS and SGP simulations,

VLBI/SLR/GPS combinations.

Mr. David Eriksson Mass loading, troposphere raytracing (intern).

Mr. Tobias Forsberg Station stabilities, vgosDB development (intern).

Ms. Julia Ringsby vgosDB development (intern).

Mr. Ronny Videkull vgosDB development (intern).

Ms. Emma Woxlin Station stabilities, vgosDB development (intern).

5 Staff

During 2013, the Analysis Center staff consisted of

one GSFC civil servant, Dr. Chopo Ma, six NVI,

Inc. employees who work under contract to GSFC,

and five temporary student interns from Chalmers

University of Technology (Sweden). Dr. Ma oversees

the GSFC VLBI project for GSFC and is also the

IVS co-representative to the IERS. Dr. John Gipson is

the GSFC VLBI Project Manager as well as the IVS

Analysis Coordinator. Table 1 lists the staff members

and their main areas of activity.

6 Future Plans

Plans for the next year include ICRF2 maintenance,

second epoch VCS observations, preparations for

ICRF3, participation in VGOS development, continued development of νSolve and the new vgosDB data

format, upgrade of program dcalc, and further research

aimed at improving the VLBI technique.

References

1. K. Baver and J. Gipson, “Refining the Uniform Sky Strategy for IVS-INT01 Scheduling”, Proceedings of the 21st

Meeting of the EVGA, N. Zubko and M. Poutanen (Editors), pages 205–209, 2013.

2. S. Bolotin, K. Baver, J. Gipson, D. Gordon, D. MacMillan,

“Status of nuSolve”, Proceedings of the 21st Meeting of the

EVGA, N. Zubko and M. Poutanen (Editors), pages 77-80,

2013.

3. K. Le Bail, J. M. Gipson, J. Juhl, D. S. MacMillan, “Optimal time lags to use in modeling the thermal deformation

of VLBI Antennas”, Proceedings of the 21st Meeting of the

EVGA, N. Zubko and M. Poutanen (Editors), pages 165–

168, 2013.

4. K. Le Bail, J. M. Gipson, D. S. MacMillan, “Quantifying

the correlation between the MEI and LOD variations by decomposing LOD with Singular Spectrum Analysis”, Proceedings of the IAG General Assembly, Melbourne, Australia, June 28–July 2, 2011; IAG Symposia, Vol. 139; Rizos, Chris; Willis, Pascal (Editors), pages 473-480, 2014.

5. David Gordon, Chopo Ma, Dan MacMillan, Sergei Bolotin,

Karine Le Bail, and John Gipson, “Effects of ICRF2 on the

TRF, CRF, and EOP”, Reference Frames for Applications in

Geosciences, IAG Symposia, Vol. 138; Z. Altimimi and X.

Collilieux (Editors), pages 175-180, 2013.

6. C. Ma, D. MacMillan, S. Bolotin, K. Le Bail, D. Gordon,

and J. Gipson, “Comparison of Realizations of the Terrestrial Reference Frame”, Reference Frames for Applications

in Geosciences, IAG Symposia, Vol. 138; Z. Altimimi and

X. Collilieux (Editors), pages 51-56, 2013.

IVS 2013 Annual Report
Haystack Observatory Analysis Center

Arthur Niell, Roger Cappallo, Brian Corey, Jason SooHoo, Mike Titus

Abstract Analysis activities at Haystack Observatory are directed towards improving the accuracy of

geodetic measurements, whether these are from VLBI,

GNSS, SLR, or any other technique. Those analysis

activities that are related to technology development

are reported elsewhere in this volume. In this report

we present some preliminary results of an analysis of

a 24-hour broadband VGOS session from May 22,

2013. The data were calibrated to obtain correlated

flux densities at X-band for a subset of the sources,

and a geodetic solution was obtained. Both analyses

led to improvements in the DiFX correlator and the

post-correlation software.

1 Introduction

The broadband instrumentation for the next generation

geodetic VLBI system, previously called VLBI2010

but now referred to as VGOS (for VLBI2010 Global

Observing System), was implemented on a new 12-m

antenna at the Goddard Space Flight Center near Washington, D.C., USA, and on the Westford 18-m antenna

at Haystack Observatory near Boston, Massachusetts,

USA. In October 2012 the first geodetic observing sessions were conducted using the broadband system. Results from these sessions were described in last year’s

Analysis Center Annual Report. In this report we highlight the procedures for obtaining correlated flux denMIT Haystack Observatory

Haystack Analysis Center

IVS 2013 Annual Report

sities and baseline results for a 24-hour session on May

22, 2013.

The features of the VGOS system are repeated here

for reference:

• four bands of 512 MHz each, rather than the two (S

and X) for standard IVS sessions

• dual linear polarization in all bands

• multitone phase cal delay for every channel in both

polarizations

• simultaneous estimation of the total electron content difference (dTEC) between sites along with

the ionosphere-free group delay using the phases

across all four bands spanning 3.2 GHz to approximately 8.8 GHz for this session.

The features indicated in the last three bullets have

required changes to the analysis of the geodetic delays, and these have been implemented in the postcorrelation software difx2mark4 and fourfit.

2 The Observations

The main objective of the 24-hour session on May 22,

2013 was to validate the quality of the calibration of

correlated flux densities on the GGAO12M-Westford

baseline. Since the largest number of potential comparison values is from the S/X observations of the geodetic

VLBI program, the highest frequency band was chosen

to lie within the range of the geodetic X-band, covering approximately 8.3 – 8.8 GHz. The frequencies of

the other three bands were the same as used in October

2012, covering 512 MHz beginning at 3.2, 5.2, and 6.3

GHz. S-band was not observed because the presence

276
Haystack Analysis Center 277

of RFI was likely to severely limit the validity of any

calibration.

The schedule was generated using sked. Because

sked does not yet have the capability to account for the

broadband parameters, the SEFDs at both S-band and

X-band for the two antennas were adjusted to allow

use of the R1 session parameters. The 100 strongest

sources were selected from the catalog of good geodetic sources. A minimum scan length of 30 seconds was

set, and the minimum SNR was 15 for both bands. The

minimum elevation was set to 5◦, and a cone about

the SLR site to the southwest of the GGAO antenna

was masked out to avoid potential damage to the LNAs

by the SLR aircraft avoidance radar. The average scan

length observed was 31 seconds, and the average number of scans per hour was 48.

The signal chain consisted of a QRFH feed, low

noise amplifiers, and phase calibration injection in the

payload near the focus for both antennas, and four UpDown Converters, RDBE-Hs, and Mark 5C recorders

in the control room. These are described more completely in Niell et al (2012).

3 Correlated Flux Density Measurements

The correlated flux density Sc for each observation was

obtained from the correlation coefficient ρ as:

Sc = b ∗ ρ ∗

p

(SEFD1 ∗ SEFD2) (1)

where

• b= 1.13 for DiFX correlator (Cappallo, private

communication)

• SEFD1,2 = System Equivalent Flux Density for

GGAO and Westford at the time of the observations.

The SEFDs in the 8 GHz band (X-band) were obtained for each scan by scaling the on-source power

level at the time of each observation to the on-source

minus off-source power difference for CasA. The measurements for CasA were made before, after, and near

the middle of the session. However, the elevations of

the source at the beginning and end were too low for

useful measurements, so only the mid-session value

was used for calibrating the correlated flux densities.

The CasA power was corrected for partial resolution of

CasA because the angular size is not negligible compared to the half-power beamwidths of the two antennas. This method of estimating the SEFD is valid provided the system gain does not vary between the observation epoch and the CasA measurement epoch, so

that system power tracks system temperature. Analysis

of the phase cal amplitudes at the two stations showed

that the gain variations were small.

The weather was stormy at Westford, and the system power varied by more than a factor of two during

the first ten hours. Water on the Westford radome was

largely responsible for the higher power levels. Besides

affecting system temperature, variations in the thickness of the radome water layer or in atmospheric attenuation at either site can also cause variations in signal

transmission loss from quasar to antenna feed. Corrections to the correlation coefficients were made for this

latter effect.

Instead of displaying the correlated flux densities,

we show, for twelve of the strongest sources and for

the vertical polarization (V-pol), the ratios between the

correlation coefficient for each scan of each source and

the median value for that source using all of the data for

the 24 hours (Figure 1). The three frames are for a) the

observed correlation coefficients directly from the correlator; b) the same but multiplied by the square root

of the product of the (equivalent of the) system temperature; c) and further corrected for absorption by the

atmosphere and by a radome water layer using a simple

model. The larger scatter for the first ten hours exhibited in 1c) is thought to be due to incomplete correction

for variations in system temperature and absorption by

the radome. For the last 14 hours, except possibly for

the source 3C418 (blue crosses), the ratios are consistent with the sources being unresolved (no change in

correlated flux density with baseline orientation). Because this is expected for good geodetic sources on this

short baseline, the result is supportive of the calibration

procedure.

4 Geodetic Analysis

The four bands were correlated independently

and were first analyzed separately with the delayestimation program fourfit to verify that the correlation

was correct before being combined into one data set.

Phase cal was applied using the ‘multitone’ option in

IVS 2013 Annual Report
278 Niell et al.

Fig. 1 The correlation coefficient ratios to the median values

at X-band for twelve sources: a) correlation coefficients from

the correlator; b) correlation coefficients corrected for on-source

power; c) furthur correction for atmospheric and radome loss.

fourfit which calculates the delay for each 32 MHz

channel from the six or seven tones spaced 5 MHz

apart. The four bands, each having two polarizations,

were then combined into one file using fourmer; then

fourfit was used to coherently estimate the group delay

for all four bands and to obtain the coefficient of the

inverse frequency dependence of the phase which is

attributed to the differenced Total Electron Content

(dTEC) between the two stations. With the application

of multitone phase cal delay, there were no cycle

ambiguities.

In order to process the observed delays through calc

to obtain the observed-minus-model residuals, it was

necessary to modify the program dbedit (D. Gordon,

private communication) to accept delays obtained from

64 channels and from which the dispersive term had

already been removed. The data were then analyzed

using the program nuSolve which is in development

by Sergei Bolotin to serve initially as a preprocessor

for batch-mode solve processing but ultimately as a replacement for solve.

For the nuSolve analysis, because this is only a single 24-hour session, the model parameterization was

relatively simple. Only the clock behavior at GGAO,

the position of GGAO for the day, and the atmosphere

zenith delays and gradients at both stations were estimated. The clock and atmospheres were modeled as

stochastic processes using the default process values

from nuSolve. Tests were made for comparison using

piecewise linear functions with intervals of ten minutes and longer, but the fits were not as good after reweighting.

Short of having a series of observations on different

days with which to assess the repeatability of observations with the two antennas, a similar comparison can

be made with independent segments within a session.

Therefore the 24-hour session was separated into independent six-hour segments. With the high observed

scan rate, there were still over 250 useful observations

in each segment. This is comparable to the number of

scans per station for a full 24 hours in an IVS session.

The length estimates for the full 24 hours and for

each of the six hour segments are shown in Figure 2.

Independent measurements of this baseline were

made in two six-hour sessions in October 2012 (Niell

et al.). The agreement for successive days for the independent polarizations was at the millimeter level.

While it would be tempting to compare the baseline

length of this May 2013 session, there is reason to refrain: measurements of the phase cal delay obtained

from the multitone phase cal processing for both sessions showed a strong dependence of delay on azimuth

for the Westford antenna, although the range of variation was different by a factor of about two. For the May

2013 data, the range of delay was about 50 psec, while

for October 2012 it was about 25 psec.

Since an uncorrected variation of azimuthal instrumental delay would be interpreted in the estimation

process as an apparent error in the horizontal position

of the antenna, it is not useful to compare the baseline

lengths for the 2012 and 2013 sessions. In the future a

cable delay measurement system will be deployed at

the sites to reduce these errors to a negligible value

(see the Technology Development Center Report for

Haystack Observatory, Beaudoin et al, this volume).

5 Outlook

Observations using the 12 m and Westford are expected to become more frequent beginning in mid2014. The correlation and data analysis chain (correlator/fourfit/solve) for the stand-alone broadband VGOS

IVS 2013 Annual Report
Haystack Analysis Center 279

Fig. 2 Baseline length between Westford and GGAO12M on

2013 May22. Red square: solution for all 24 hours of data; blue

diamonds: independent six hour segment analyzed with the same

parameterization as the full 24-hour solution.

observations and for the mixed broadband-Mark IV observations needs to be developed and made operational.

As a first step in facilitating these developments nuSolve has been installed at Haystack and was used for

most of the geodetic analysis described in this report.

A next step will be to begin to use the vgosDB format,

followed by installation of the full calc/solve/nuSolve

suite of programs.

Acknowledgements

We thank the Broadband Development group for their

efforts in constructing, implementing, and operating

the systems at GGAO and at Westford and for assisting

in the testing and observations; John Gipson for guidance in getting sked to work; David Gordon for getting the broadband output into databases; and Sergei

Bolotin for developing nuSolve, getting it to work with

the new broadband observable, and providing some of

the solutions.

References

1. Niell et al., “First Broadband Results with a VLBI2010 System”, IVS 2012 General Meeting Proceedings, edited by D.

Behrend and K. Baver, NASA-CP-2012-217504, pages 13-

17.

IVS 2013 Annual Report
IAA VLBI Analysis Center Report 2013

Elena Skurikhina, Sergey Kurdubov, Vadim Gubanov, Daniil Shigaev

Abstract This report presents an overview of the IAA

VLBI Analysis Center activities during 2013 and the

plans for the coming year.

1 General Information

The IAA IVS Analysis Center (IAA AC) is located

at the Institute of Applied Astronomy of the Russian

Academy of Sciences in St. Petersburg, Russia. The

IAA AC contributes to IVS products, such as daily

SINEX files, TRF, CRF, rapid and long-term series

of EOP, baseline lengths, and tropospheric parameters.

EOP, UT1, and station positions were estimated from

domestic observation programs Ru-E and Ru-U. The

IAA AC generates NGS files.

2 Activities during the Past Year

2.1 Software Development for VLBI

Processing

The QUASAR software is capable of calculating all

types of IVS products. The possibility of outputing

source positions to DSNX files was realized.

Institute of Applied Astronomy of RAS

IAA Analysis Center

IVS 2013 Annual Report

2.2 Routine Analysis

During 2013 the IAA AC continued to submit daily

SINEX files for the IVS-R1 and IVS-R4 sessions as

rapid solution (iaa2010a.snx) and SINEX files based

on all 24-hour experiments for the quarterly solution.

The routine data processing was performed with the

OCCAM/GROSS software using a Kalman Filter. The

IAA AC operationally processed the “24h” and Intensive VLBI sessions and submitted the results to the

IERS and IVS on a regular basis. Processing of the

Intensive sessions is fully automated. The EOP series

iaa2007a.eops and iaa2005a.eopi and troposphere parameters iaa2007a.trl were continued. Long-term series of station coordinates, baseline lengths, and tropospheric parameters (ZTD and gradients) were computed with the station position catalog ITRF2005.

2.3 Global Solution

iaa2012crf and iaa2012trf were submitted to IVS. A

new global solution was calculated using all available data from 1980 until 2012 (through the end of

September 2012 we had 5,654 sessions). A total of

6,912,198 delays were processed. The CRF was fixed

by NNR constraints to 212 radio sources. The TRF

was fixed by NNR and NNT constraints to the station positions and velocities of 15 stations: MATERA,

KOKEE, WETTZELL, FORTALEZA, WESTFORD,

ALGOPARK, NYALES20, ONSALA60, HARTRAO,

BR-VLBA, FD-VLBA, HN-VLBA, KP-VLBA, LAVLBA, and NL-VLBA. Stochastic signals were estimated by means of the least-squares collocation technique. The radio source coordinates, station coordi280
IAA AC 2013 AR 281

nates, and corresponding velocities were estimated as

global parameters. EOP, WZD, troposphere gradients

and station clocks were estimated as arc parameters for

each session. 6,690 global parameters were estimated:

3,635 source positions, and the positions of the velocities of 156 VLBI stations.

2.4 EOP Parameter Calculation from

Domestic “Quasar” Network

Observations

VLBI observations using the “Quasar” network for

EOP monitoring are carried out in the framework of

two domestic programs: Ru-E and Ru-U.

The purpose of the Ru-E program is to provide EOP

results on a regular basis from 24-hour sessions using

three-station network: “Svetloe” – “Zelenchukskaya” –

“Badary”.

The purpose of the Ru-U program is to provide

UT1-UTC results on a regular basis from Intensive sessions using one baseline “Badary” – “Zelenchukskaya”

(“Badary” – “Svetloe”).

Correlation analysis is performed using the IAA

ARC correlator.

Observational data from 1-hour Ru-U sessions

are transmitted to the correlator using e-VLBI data

transfer. Calculation of UT1 time series is performed

automatically. The result is a UT1-UTC time series

available at ftp://quasar.ipa.nw.ru/pub/EOS/IAA/eopiru.dat.

Since April 2013 we have used e-VLBI data transfer for the data of 24-hour observations from “Badary”

and “Zelenchukskaya”. Data of 24-hour sessions are

shipped to the IAA correlator on disk modules only

from “Svetloe” observatory. The EOP time series is

available at ftp://quasar.ipa.nw.ru/pub/EOS/IAA/eopsru.dat.

During 2013, 48 Ru-E and 356 Ru-U sessions were

observed. AC IAA performed analysis of these observations. The accuracy obtained in 2013 for EOPs in

comparison to the IAA EOP 08 C04 series is presented

in Table 1.

Table 1 RMS differences with EOP IERS 08 C04.

EOP Nsess Bias RMS

Xp, mas 48 0.45 0.97

Yp, mas 48 -0.67 1.23

UT1-UTC,μs 48 -15 35

Xc,mas 48 -0.13 0.34

Yc, mas 48 -0.19 0.33

UT1-UTC Int., μs 356 25 67

2.5 CONT11 Data Analysis

Secondary treatment of the CONT11 program’s observations was carried out using software package OCCAM/GROSS. In the calculation of diurnal EOP, 15

daily sessions were combined into one 15-day session (consisting of 16,430 scans and 145,214 delays),

which was processed using package OCCAM/GROSS

using the forward run of the Kalman filter to estimate

the stochastic parameters. As stochastic parameters are

considered EOP (pole coordinates and universal time),

the date, time, wet component of the tropospheric delay

at the zenith (WZD).

Diurnal variations of Xpol, Ypol, and dUT1 were

compared with the model of diurnal variations from the

EOP IERS Conventions (2003) model of subdaily EOP

variations (designated here as “model”). The results are

presented in Figure 1. RMS differences between EOP

and the model are presented in Table 2.

Table 2 CONT11: RMS differences between EOP and “model”.

EOP Npoint RMS

Xp, μas 16123 167

Yp, μas 16123 164

dUT1,μs 16123 18

The values of Tropospheric Total Zenith Delay

(TZD) obtained during CONT11 from VLBI are

in good agreement with data obtained from GPS

observations. The results are presented in Figure 2.

IVS 2013 Annual Report
282 Skurikhina et al.

-100

 0

 100

 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

dUT1, μs

CONT11 day number (MJD - 55819.0)

dUT1 error

dUT1

model

-1

 0

 1

Yp, mas

Yp error

Yp

model

-1

 0

 1

Xp, mas

Xp error

Xp

model

Fig. 1 EOP intra-day variations from CONT11.

2.6 Study of Systematic Errors of

Reference Frames

First, directly from the data processing of VLBI observations from about 30 years and using systematic

errors obtained from the QUASAR software, coordinates for ICRF2 radio sources were calculated as twodimensional maps of distributions of radio source position errors on the celestial sphere and orthonormal

expansion in spherical harmonics up to the ninth order.

At some areas, the value of the errors is about 1 mas.

Radio source and station position variations were then

analyzed to study reference frame stability.

3 Current Status

The IAA AC performs data processing of all kinds of

VLBI observation sessions. For VLBI data analysis,

we use the QUASAR and the OCCAM/GROSS software packages. All reductions are performed in agreement with IERS Conventions (2010). Both packages

use NGS files as input data.

The IAA AC submits to the IVS Data Center all

kinds of products: daily SINEX files for EOP and EOPrates and station position estimates, TRF, CRF, baseline length, and tropospheric parameters.

The QUASAR and the OCCAM/GROSS software

packages are supported and being developed.

 2000

 2200

 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

CONT11 day number (MJD - 55819.0)

Zelenchukskaya, rms TZD(VLBI-GPS) = 7,4 mm, bias = -3.3 mm

 2100

 2200

 2300

Yebes, rms [TZD(VLBI-GPS)] = 5,5 mm, bias = -4.7 mm

 2200

 2400 Wettzell, rms [TZD(VLBI-GPS)] = 4,6 mm, bias = -1.0 mm

 2400

 2600 Westford, rms [TZD(VLBI-GPS)] = 5,4 mm, bias = -2.0 mm

 2300

 2400

Concepcion, rms [TZD(VLBI-GPS)] = 4,4 mm, bias = -2.4 mm

 2400

 2600

Tsukuba, rms [TZD(VLBI-GPS)] = 5,6 mm, bias = -1.2 mm

 2300

 2400

Ny Alesund, rms [TZD(VLBI-GPS)] = 4,6 mm, bias = -1.2 mm

 2300

 2500 Onsala, rms [TZD(VLBI-GPS)] = 4,7 mm, bias = -1.4 mm

 2100

 2200 Kokee, rms [TZD(VLBI-GPS)] = 2,8 mm, bias = 0.3 mm

 2300

 2400

Hobart12, rms [TZD(VLBI-GPS)] = 2,5 mm, bias = 0.2 mm

 2000

 2200 Hartebeeshoek, rms [TZD(VLBI-GPS)] = 1,7 mm, bias = 0.3 mm

 2150

 2250 Badary, rms [TZD(VLBI-GPS)] = 1,3 mm, bias = 0.1 mm

Fig. 2 TZD intra-day (VLBI compared with GPS) variations

from CONT11.

4 Future Plans

We plan to:

• Continue to submit all types of IVS product contributions.

• Continue investigations into VLBI estimation of

EOP, station coordinates, and tropospheric parameters, and comparison with satellite techniques.

• Further improve algorithms and software for processing VLBI observations.

• Contribute to ICRF3 Working Group study.

IVS 2013 Annual Report
Italy INAF Analysis Center

Monia Negusini, Pierguido Sarti

Abstract This report summarizes the activity of the

Italian INAF VLBI Analysis Center. Our Analysis

Center is located in Bologna, Italy and belongs to the

Institute of Radio Astronomy (IRA), which is part of

the National Institute of Astrophysics (INAF). IRA

runs the observatories of Medicina and Noto, where

two 32-m twin VLBI AZ-EL telescopes are located.

This report contains the AC’s VLBI data analysis

activities and illustrates the local surveys carried out in

2013 at IRA observatories.

1 Current Status and Activity

The ITRF2013 Call for Participation (CfP) was issued

at the end of March 2013. According to the call, “the

owners of co-location sites are solicited and highly encouraged to consider conducting new local tie surveys

using the most up to date survey methods. The results

of least squares adjustments of the survey observations

should be provided to the ITRS Center in the form of

SINEX format, with full variance-covariance information.” The submission of the new tie vectors linking the

co-located space geodetic instruments was due as early

as possible and no later than the end of February 2014.

The CfP and its deadline induced us to plan new

local tie surveys at both Medicina and Noto by the

summer of 2013. In particular, the tie vector at the

Medicina site was surveyed during June 2013 (from

June 11th until June 14th) and the tie vector at Noto

Istituto di Radioastronomia INAF, Bologna

INAF Analysis Center

IVS 2013 Annual Report

was surveyed during three full days from July 10th until July 12th, 2013. The method that was adopted to

conduct the surveys is based on the well-established

protocol described in several papers [1, 2]. As usual,

the surveys were carried out in close cooperation with

the Department of Civil, Chemical, Environmental, and

Material Engineering (DICAM) of the University of

Bologna. Three high quality total stations from Leica (TDA5005, TS30, and TCA2003, http://www.leicageosystems.com) were contemporarily used to minimize the observation time and increase the total number of measurements available to estimate the conventional reference point of the VLBI telescopes. Following the ITRF2013 CfP requirements, the GPS antennas

were not removed to avoid undesirable possible discontinuity in the position time series when the antenna

is restored back to its original marker. This was easily

achieved following the GPS choke ring antenna survey

approach described in detail in [1].

The surveys and the computation of the tie vectors

at both sites were performed as part of a ten-week internship project agreed upon between the IRA and the

IGN School in Geomatic Sciences, Ecole Nationale des

Sciences Geographiques (ENSG) in Marne la Vall  ́ ee,  ́

France. The internship involved Mr. Clement Iphar, a  ́

student of the school interested in geodesy and in the

applications of terrestrial geodetic techniques for the

computation of the ITRF.

The alignment of the tie vectors into the ITRF from

the local topocentric frame was achieved using a set

of points surveyed with both terrestrial techniques and

GPS. The tie vectors were submitted in September

2013 to the ITRS Center in Paris and are now available

for the computation of the new ITRF2013.

It is worth mentioning that the 2013 survey in

Medicina confirms the general trends reported in

283
284 Negusini and Sarti

[3], with a striking stability of the tie vector Up

component. The details and the results of the surveys

will be summarized and discussed in two reports that

will be submitted to the ITRS Center.

2 Data Analysis and Results

The IRA started to analyze VLBI geodetic databases in

1989, using a CALC/SOLVE package on the HP1000

at the Medicina station. In subsequent years, the same

software was installed first on an HP360 workstation

and later on an HP715/50 workstation. In more recent

years, two HP785/B2600 workstations and an HP282

workstation were used. In 2007, a new Linux workstation was set up for the migration of all the VLBI data

analysis, and Mark 5 Calc/Solve was installed. During

2013, our Analysis Center continued its participation

in the IVS TROP Project on Tropospheric Parameters.

Tropospheric parameters (wet and total zenith delay

and horizontal gradients) of all IVS-R1 and IVS-R4

24-hour VLBI sessions were regularly submitted.

3 Outlook

We will continue with the regular submission of INAF

tropospheric parameters to the IVS Data Center. We

are also going to monitor the GPS-VLBI tie vectors at

our sites on a regular basis, possibly every second year,

to continue the investigations into the local movements

and into the local site stability.

References

1. Sarti, P., Sillard, P., Vittuari, L. (2004) Surveying colocated space geodetic instruments for ITRF computation.

J Geodesy 78(3):210–222, doi: 10.1007/s00190-004-0387-

0.

2. Sarti, P., Abbondanza, C., Vittuari, L. (2009) Gravity dependent signal path variation in a large VLBI telescope modelled with a combination of surveying methods. J Geodesy

83(11):1115–1126, doi: 10.1007/s00190-009-0331-4.

3. Sarti, P., C. Abbondanza, J. Legrand, C. Bruyninx, L. Vittuari, J. Ray. (2013) Intrasite motions and monument instabilities at Medicina ITRF co-location site. Geophys J Int

192:1042–1051, doi: 10.1093/gji/ggs092.

IVS 2013 Annual Report
JPL VLBI Analysis Center Report for 2013

Christopher S. Jacobs

Abstract This report describes the activities of the

JPL VLBI Analysis Center for the year 2013. Highlights for the year include the start of operations for the

combined NASA-ESA Ka-band network, installation

of our Digital Back Ends enabling 1024–2048 Mbps

operations, and our first installation of a Ka-band phase

calibrator. We continue to support VLBI-based navigation using our combined spacecraft, celestial reference frame, terrestrial reference frame, earth orientation, and planetary ephemeris VLBI systems.

1 General Information

The Jet Propulsion Laboratory (JPL) Analysis Center is

in Pasadena, California. Like the rest of JPL, the center

is operated by the California Institute of Technology

under contract to NASA. JPL has done VLBI analysis

since about 1970. We focus on spacecraft navigation,

including:

1. Celestial Reference Frame (CRF) and Terrestrial

Reference Frame (TRF), which are efforts that provide infrastructure to support spacecraft navigation

and Earth orientation measurements.

2. Time and Earth Motion Precision Observations

(TEMPO), which measures Earth orientation

parameters based on single baseline semi-monthly

measurements. These VLBI measurements are then

combined with daily GPS measurements as well as

other sources of Earth orientation information. The

Jet Propulsion Laboratory, California Institute of Technology

JPL Analysis Center

IVS 2013 Annual Report

combined product provides Earth orientation for

spacecraft navigation.

3. Delta differenced one-way range (∆DOR), which

is a differential VLBI technique that measures

the angle between a spacecraft and an angularly

nearby extragalactic radio source. This technique

thus complements the radial information from

spacecraft doppler and range measurements

by providing plane-of-sky information for the

spacecraft trajectory.

2 Technical Capabilities

The JPL Analysis Center acquires its own data and supplements it with data from other centers. The data we

acquire are taken using NASA’s Deep Space Network

(DSN).

1. Antennas: Most of our work uses 34-m antennas

located near Goldstone (California, USA), Madrid

(Spain), and Tidbinbilla (Australia). These include

the following Deep Space Stations (DSS): the

“High Efficiency” subnet comprised of DSS 15,

DSS 45, and DSS 65 which has been the most

often used set of JPL antennas for VLBI. More

recently, we have been using the DSN’s beam

waveguide (BWG) antennas: DSS 13, DSS 24,

DSS 25, DSS 26, DSS 34, DSS 54, and DSS 55.

Less frequent use is made of the DSN’s 70-m

network (DSS 14, DSS 43, and DSS 63). Typical

X-band system temperatures are 35K on the HEF

antennas. The 70-m and BWGs are about 20K.

Antenna efficiencies are typically well above 50%

at X-band.

285
286 Jacobs

2. Data acquisition: We use ROACH-based Digital

Back Ends with Mark 5C VLBI recorders. These

units are now in the field and are expected to become fully operational in 2014. In addition, we

have JPL-unique systems called the VLBI Science

Recorder (VSR) and the Wideband VSRs (WVSR)

which have digital baseband converters and record

directly to hard disk. The data are later transferred

via network to JPL for processing with our software

correlator.

3. Correlators: The JPL VLBI Correlator has been exclusively based on the SOFTC software which handles the ∆DOR, TEMPO, and CRF correlations as

well as tests of antenna arraying.

4. Solution types: We run several different types

of solutions. For ∆DOR spacecraft tracking we

make narrow field (≈ 10◦) differential solutions.

The TEMPO solutions typically have a highly

constrained terrestrial (TRF) and celestial frame

(CRF) as a foundation for estimating Earth orientation parameters. These reference frames are

produced from global solutions which then provide

the framework needed for use by TEMPO and

∆DOR.

3 Staff

Our staff are listed below along with areas of concentration. Note that not all of the staff listed work on

VLBI exclusively as our group is involved in a number of projects in addition to VLBI.

• Durgadas Bagri: TEMPO and Ka-band phase calibrators.

• James Border: ∆DOR spacecraft tracking.

• Cristina Garc ́ıa-Miro: Madrid data acquisition,  ́

NASA-ESA southern declination collaboration,

and educational outreach.

• Shinji Horiuchi: Canberra data acquisition and

NASA-ESA southern declination collaboration.

• Chris Jacobs: NASA-ESA southern declination collaboration, X/Ka CRF, TRF, and S/X CRF.

• Christina King: source stability studies.

• Peter Kroger: ∆DOR spacecraft tracking.

• Gabor Lanyi: MODEST, Fringe fitting and correlation support, ∆DOR, and TRF.

• Steve Lowe: Software correlator, fringe fitting software, and ∆DOR.

• Walid Majid: pulsars, ∆DOR, and VLBA phase referencing.

• Chuck Naudet: NASA-ESA southern declination

collaboration and source stability studies.

• Andres Romero-Wolf: ∆DOR, CRF and TRF.

MODEST scripts. Source stability studies.

• Lawrence Snedeker: Goldstone data acquisition.

NASA-ESA southern declination collaboration.

• Ojars Sovers: S/X, and X/Ka CRFs and TRF. Maintains MODEST analysis code.

• Alan Steppe: TEMPO and TRF.

4 Current Status and Activities

The TEMPO task’s EOP measurements continue.

Our S/X CRF work is being downsized in favor of

X/Ka-band (8.4/32 GHz) CRF which continues to

make major strides forward. In particular, in 2013,

ESA’s Malargue, Argentina antenna became a regular  ̈

part of our Ka-band network adding much needed

southern coverage, and DSN operations moved to

1024 to 2048 Mbps.

VLBI spacecraft tracking continues to provide

measurements of angular position in support of

mission navigation and planetary ephemeris development. The New Horizons trajectory toward Pluto was

verified with a series of Delta-DOR measurements

in June-August 2013. Delta-DOR data were used to

assure the Earth-flyby targeting for Juno in October

2013. Dawn is being supported with Delta-DOR

during its low thrust cruise from Vesta to Ceres.

Monthly Delta-DOR measurements of MRO and Mars

Odyssey continue to improve the ephemeris of Mars.

Delta-DOR measurements have begun on both the

NASA mission Maven and the ISRO mission MOM to

support navigation during their cruise to Mars.

5 Future Plans

In 2014, we hope to improve our VLBI system by making our Digital Back End, the DVP, compatible with the

JIVE and DiFX correlators, thereby enabling broader

calibrations. We hope to deploy operational Ka-band

phase calibrators at our overseas sites. We expect the

combined NASA-ESA deep space network to reach

IVS 2013 Annual Report
JPL Analysis Report 287

sub-nanoradian (200 μas) Ka-band CRF results over

the south polar cap (−90◦ < δ < −45◦

). On the spacecraft front, we plan to continue supporting a number

of operational missions while further improving techniques for using VLBI for spacecraft tracking.

Acknowledgements

Research described herein done in part at the Jet

Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics

and Space Administration. Government sponsorship acknowledged. Copyright 
c 2014. All Rights

Reserved.

References

1. A. Bertarini, A de Witt, C.S. Jacobs, J. McCallum, T. Jung,

J. Quick, S. Horiuchi, J. Lovell, B. Won Sohn, R. Ojha,

‘Extending the K-band Celestial Frame with Emphasis on

the Southern Hemisphere,’ Journees Syst  ́ emes de R ` ef ́ erence  ́

Spatio-Temporels, Paris, 16 Sept. 2013.

syrte.obspm.fr/journees2013/powerpoint/bertarini jsr13.pdf

2. David W. Curkendall and James S. Border, ‘Delta-DOR:

The One-Nanoradian Navigation Measurement System of

the Deep Space Network: History, Architecture, and Componentry,’ Interplanetary Network Progress Report, vol. 42-

193, Jet Propulsion Laboratory, Pasadena, CA, pp. 1–46,

May 15, 2013.

http://ipnpr.jpl.nasa.gov/progress report/42-193/193D.pdf

3. A. de Witt, A. Bertarini, C.S. Jacobs, J. McCallum, T. Jung,

J. Quick, S. Horiuchi, J. Lovell, B. Won Sohn, R. Ojha,

‘Experimental plan for improving the K-band Celestial

Frame,’ Journees Syst  ́ emes de R ` ef ́ erence Spatio-Temporels,  ́

Paris, 16 Sept. 2013.

syrte.obspm.fr/journees2013/powerpoint/dewitt poster

jsr13.pdf

4. R. Gaume, C.S. Jacobs, and ICRF-3 working group, ICRS

Product Center and IAU ICRF-3 WG Update, IERS directing board meeting #57, San Francisco, 8 Dec 2013.

5. R. Heinkelmann, C.S. Jacobs and ICRF-3 working group

‘The ICRF-3: A Proposed Roadmap to the next generation International Celestial Reference Frame,’ IAG, Potsdam, Germany, 1-6 Sept 2013.

http://www.iag2013.org/IAG 2013/Potsdam.html

6. S. Horiuchi, J.E. Clark, C. Garc ́ıa-Miro, C.S. Jacobs, R.  ́

Madde, M. Mercolino, L.G. Snedeker, I. Sotuela, L.A. `

White ‘X/Ka Celestial Frame,’ Asia-Pacific Radio Science

Conference, Tapei, Taiwan, 3-7 Sept. 2013.

http://aprasc13.ntu.edu.tw/Program2/AdvanceProgram.

asp#J1b

7. C.S. Jacobs, ‘Celestial Reference Frames,’ overview lecture

for the 1st EVGA School, Aalto University, Otaniemi,

Espoo, Finland, 5 March 2013.

http://www.evga.org/teaching/VLBI school 2013/VLBIschool-2013 16 Jacobs.pdf

8. C.S. Jacobs, J.E. Clark, J. de Vicente, M. Dugast, C.

Garc ́ıa-Miro, C.E. Goodhart, S. Horiuchi, S.T. Lowe,  ́

R. Madde, M. Mercolino, C.J. Naudet, L. G. Snedeker, `

I. Sotuela, L.A. White, ‘Extending the X/Ka Celestial

Reference Frame to the South Polar Cap: Results from

Combined NASA-ESA Baselines to Malargue, Argentina,’  ̈

21st EVGA Symposium, Espoo, Finland, 7 March 2013.

http://evga.fgi.fi/sites/default/files/u3/Jacobs XKa EVGA2013.pdf

http://adsabs.harvard.edu/abs/2013evga.confE...1J

9. C.S. Jacobs, J. Bohm, P. Charlot, and the joint IAU ICRF-3  ̈

working group and IAG sub-comission 1.4 ‘ICRF-3: An Assessment of Needs and Plans for the Future,’ ICRF-3 joint

IAU/IAG splinter meeting to 21st EVGA Symposium, Espoo, Finland, 7 March, 2013.

http://evga.fgi.fi/node/9

10. C.S. Jacobs, R. Gaume, C. Ma, and ICRF-3 working group,

‘ICRF-3 Overview,’ IERS Directing Board Retreat, Paris,

France, 23 May 2013

11. C.S. Jacobs and the ICRF-3 working group, ‘The ICRF-3:

Proposed Roadmap to the Next Generation International Celestial Reference Frame,’ Journees Syst  ́ emes de `

Ref ́ erence Spatio-Temporels, Paris, 16 Sept. 2013.  ́

http://syrte.obspm.fr/journees2013/powerpoint/jacobs jsr13

.pdf

12. C.S. Jacobs, ‘Celestial Reference Frames,’ Journees 2013,  ́

Tutorial session, Paris, 15 Sept 2013.

syrte.obspm.fr/jsr/journees2013//powerpoint/Tutorial CRF

Jacobs jsr13.pdf

13. M. Soriano, C. Jacobs, R. Navarro, C. Naudet, S. Rogstad,

L. White, S. Finley, C. Goodhart, E. Sigman, J. Trinh, J.

Lobo Garcia, C. Garc ́ıa-Miro, M. Mercolino, R. Madd  ́ e,`

‘Improved Spacecraft Tracking and Navigation Using a

Portable Radio Science Receiver,’ IEEE, Big Sky Montana,

2-9 March 2013.

doi: 10.1109/AERO.2013.6496851

http://adsabs.harvard.edu/abs/2013aero.confE...1S

http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=

649685

IVS 2013 Annual Report
KASI Combination Center 2013 Annual Report

Younghee Kwak, Jungho Cho

Abstract This report presents the activities of the

Korea Astronomy and Space Science Institute (KASI)

Combination Center during 2013 and outlines the

planned tasks for 2014. In 2013, we focused on

coordinate time series and a VLBI terrestrial reference

frame using seven-year IVS products. During the

combination using Bernese GNSS Software Version

5.0, we found restrictions on combining products. We

report those and desirable features.

1 General Information

KASI is a government-funded research institute for Astronomy and Space Science. Thus, it has a wide range

of research areas observing the Earth, the Sun, stars,

and galaxies based on various instruments. For Earth

observation, space geodesy is one of the important research fields of KASI. KASI operates GNSS, VLBI,

and SLR stations and analyzes their observation data.

2 Component Description

KASI is in charge of operating an IVS Combination

Center. KASI has rich experience in GNSS data processing and analysis using Bernese GNSS Software

(hereafter Bernese). Bernese, especially the subprogram ADDNEQ2, supports stacking of normal equations and estimation of parameters [1]. We adopted

Korea Astronomy and Space Science Institute

KASI Combination Center

IVS 2013 Annual Report

Bernese to combine the sessionwise VLBI products of

the IVS Analysis Centers (ACs) at the normal equation

level. We modified the software, which was developed

for GNSS data processing and analysis, to handle IVS

products properly. The inputs to Bernese are the normal

equation matrices and vectors from the daily SINEX

files of the individual ACs (Table 1). The outputs are

daily SINEX files including combined station coordinates and Earth orientation parameters (EOPs). The

missions of the KASI Combination Center are creation

of high quality combination products, mutual verification with the BKG/DGFI Combination Center, quality

control of the ACs’ results, provision of feedback to the

Analysis Centers, and adherence to the IERS Conventions.

Table 1 IVS ACs which KASI combined.

AC Time span Software Number of sessions

BKG 2003.0-2010.0 CALC/SOLVE 938

DGFI 2003.0-2010.0 OCCAM 891

GSFC 2003.0-2010.0 CALC/SOLVE 939

OPA 2003.0-2010.0 CALC/SOLVE 928

USNO 2003.0-2010.0 CALC/SOLVE 802

3 Staff

The staff members of the KASI Combination Center

are listed below.

288
KASI 2013 Report 289

Table 2 Personnel of the KASI Combination Center.

Jungho Cho +82-42-865-3234 jojh@kasi.re.kr

∗ Younghee Kwak +82-42-865-2031 bgirl02@kasi.re.kr

∗ until March 21, 2014

4 Current Status and Activities

(1) Coordinate Time Series

The station position coordinates for each session

were combined and estimated using the normal equations of each IVS AC summarized in Table 1 in order to

verify the VLBI combination capability of Bernese. In

total, 43 station coordinates were estimated. Figures 1,

2 and 3 show the examples of the time series for the latitude, longitude, and height of three of the 43 stations

(Westford, Wettzell, and Kokee). In the figures, the red

(darker) line represents the estimated values, and the

green (lighter) line shows the a priori values based on

ITRF2008. In each plot, a single tick mark of the vertical axis corresponds to about 1 m. It is obvious that

the errors of the longitude components are relatively

larger than those of the latitude and height components.

For 43 stations, the root mean square (RMS) errors of

the latitude and longitude components are 15.6 mm and

37.7 mm, respectively, and the error of the height component is 30.9 mm, with respect to ITRF2008 (a priori

value).

Most VLBI results provide UT1-TAI values,

while Bernese, which is the software for GNSS, can

process only UT1-UTC values at the moment. For the

normal equations of some ACs (BKG, GSFC, OPA,

and USNO), which were entered in the software, the

difference (leap seconds) between the UT1-TAI and

UT1-UTC values was included. UT1 is a parameter

that represents the rotation of the Earth, and it is

correlated with longitude that has the same direction.

Consequently, the UT1 errors of some ACs were

included in the results of the longitude, and thus the

longitude component showed a larger RMS error than

the latitude and height components. In the future,

the software needs to be improved regarding UT1

correction.

(2) VLBI TRF

We estimated TRF by combining the normal equations of five ACs (Table 1) during seven years (2003-

Fig. 1 Coordinate time series of Westford during 2003-2009.

2009) as one normal equation. Figure 4 shows the velocity vectors of the combined TRF (red arrows) by

KASI and the ITRF2008 (blue arrows). ITRF2008 is

the result that combined the data from the four space

geodetic techniques (GNSS, VLBI, SLR, and DORIS)

which had been accumulated for 25 years (1984-2008).

Thus, the stations, which had performed observations

up to 2003, exist only on ITRF2008. The YEBES staIVS 2013 Annual Report
290 Kwak and Cho

Fig. 2 Coordinate time series of Wettzell during 2003-2009.

tion in Spain dismantled the 14-m antenna that had

been used from 1995 to 2003. Accordingly, as for the

data from the YEBES station used for the combined

TRF, the observation period was very short (less than

one year), and thus the estimation of a proper velocity

vector was not available. Therefore, it had a completely

different magnitude and direction, compared to the velocity vector from ITRF2008, and it was excluded from

Fig. 3 Coordinate time series of Kokee during 2003-2009.

Figure 4. The velocity vector of the remaining 42 stations excluding the YEBES station showed a magnitude difference of 7.3 mm/yr (30.2%) and a direction

difference of 13.8◦(3.8%), with respect to ITRF2008.

Those errors are thought to be due to the longitude

component error mentioned above. As there is a large

error in the longitude component, the Helmert transformation, which represents the relation between TRFs, is

IVS 2013 Annual Report
KASI 2013 Report 291

180 ̊

180 ̊

210 ̊

210 ̊

240 ̊

240 ̊

270 ̊

270 ̊

300 ̊

300 ̊

330 ̊

330 ̊

0 ̊

0 ̊

30 ̊

30 ̊

60 ̊

60 ̊

90 ̊

90 ̊

120 ̊

120 ̊

150 ̊

150 ̊

180 ̊

180 ̊

−60 ̊ −60 ̊

−30 ̊ −30 ̊

0 ̊ 0 ̊

30 ̊ 30 ̊

60 ̊ 60 ̊

2 cm/y

Fig. 4 Velocity map of ITRF2008 (blue/slightly darker) and combined TRF (red) by KASI.

not meaningful at the moment. Thus, it was not considered in this report.

5 Future Plans

In 2014 and beyond, we will focus on the following

tasks:

• Proper UT1 correction in Bernese

• Combining whole period IVS products (1984-

present)

• Outlier rejection

• Weighting the individual solutions

• Comparing with BKG/DGFI Combination Center

[2], IERS 08C04 [3], and IGS solutions [4]

• Providing IVS EOP format solutions [2] (Rapid and

Quarterly)

• Providing VLBI TRF

References

1. Dach, R., Hugentobler, U., Fridez, P., and Meindl, M. (eds.),

Bernese GPS Software Version 5.0 User manual, Astronomical Institute, Universtiy of Bern, 2007

2. http://ccivs.bkg.bund.de

BKG/DGFI Combination Center Web page

3. http://hpiers.obspm.fr/eop-pc

IERS Earth Orientation Center Web page

4. http://igscb.jpl.nasa.gov/components/prods.html

IGS Products Table

IVS 2013 Annual Report
KTU-GEOD IVS Analysis Center Annual Report 2013

Emine Tanır Kayıkc ̧ı 1, Kamil Teke 1,2

Abstract This report summarizes the activities of

the KTU-GEOD IVS Analysis Center (AC) in 2013

and outlines the planned activities for the year 2014.

Determination of optimal weights of constraints on

VLBI auxiliary parameters as well as estimation interval lengths have been our specific interests in 2013.

1 General Information

KTU-GEOD IVS Analysis Center (AC) is located at

the Department of Geomatics Engineering, Karadeniz

Technical University, Trabzon, Turkey.

2 Staff at KTU-GEOD Contributing to the

IVS Analysis Center

The staff who are contributing to the research at the

KTU-GEOD IVS Analysis Center (AC) in 2013 are

listed in Table 1 with their working location.

3 Current Status and Activities

During 2013, we focused on determining estimation

intervals and the optimal weights of constraints on

1. Karadeniz Technical University, Department of Geomatics

Engineering

2. Hacettepe University, Department of Geomatics Engineering

KTU-GEOD Analysis Center

IVS 2013 Annual Report

Table 1 Staff.

Name Working Location

Emine Tanır Karadeniz Technical University,

Kayıkc ̧ı Dept. of Geomatics Engineering,

Trabzon, Turkey.

Kamil Teke Hacettepe University,

Dept. of Geomatics Engineering,

Ankara, Turkey.

the estimated VLBI auxiliary parameters. The main

part of this study was conducted during the research

stay of AC member Dr. Tanır Kayıkc ̧ı at HelmholtzZentrum Potsdam Deutsches GeoForschungsZentrum

GFZ from July to September 2013. The first results of

this study were presented at the International Association of Geodesy (IAG) Scientific Assembly held at

Potsdam from 1st to 6th of September 2013 [4]. The

proceedings paper of this report was submitted to the

International Association of Geodesy Symposia Series

(still under review process).

The variety of the parameterizations in VLBI analysis causes significant differences in the estimates even

if the same observations (sessions) are involved (c.f.

[2]). The space geodetic technique specific parameters in a least-squares adjustment are not standardized

— e.g., several reduction models are recommended by

the IERS Conventions 2010 ([3]). The current version

of Vienna VLBI Software (VieVS, [1]) in the leastsquares adjustment mode uses a standard parameterization for the auxiliary parameters, i.e., a piece-wise

linear offset representation with a default temporal resolution of e.g. 60 minutes for clocks and zenith wet

delays (ZWD) and six hours for troposphere horizontal north and east gradients (NGR and EGR). From the

physical point of view, the interval length should be

292
KTU-GEOD Annual Report 2013 293

as short as possible to optimally represent the behaviors of the underlying processes: from the mathematical point of view, however, the interval length should

be long enough to achieve an appropriate redundancy

of observations required to obtain a stable (regular)

normal equation system. In this study, three different

approaches are investigated for achieving optimized

parameterizations of the auxiliary parameters per station for each session. The performance of the three approaches is investigated by analyzing VLBI data with

the least-squares adjustment model of VieVS.

3.1 Approach1: Solution Intervals

Considering the Time Dependent

Behaviours of the Parameters

In the standard VLBI least-squares solution, the estimation intervals of the auxiliary parameters are usually set to be constant for the sake of simplicity, because there is no a priori information about the variability of the modelled phenomena, e.g. troposphere.

Consequently, our first optimization (approach1) realizes the idea of a flexible parameter estimation interval depending on the behavior of the parameters determined with a prior estimation featuring an equally

spaced standard parameterization. Thus, if the variation is relatively large, the parameter estimation interval will be decreased to allow for a larger degree of

freedom for this specific parameter over an appropriate

duration. With this approach it is possible to flexibly

handle the parameter estimation interval according to a

first standard solution while keeping the overall number of parameters constant. It would also be possible

to repeat the application of approach1 in an iterative

way whenever the session is reanalyzed. This iterative

optimization will be considered in future, but it is not

treated in this report.

3.2 Approach2: Solution Intervals

Considering Data Gaps

There is a usual time difference of several minutes or

more between successive VLBI observations. A significant number of VLBI sessions show gaps between

successive observations at certain stations. For example, during the CONT08 session WETTZELL stopped

and performed an Intensive VLBI session of about one

hour duration together with another network station

(see Figure 1). In our investigation, we consider a time

difference of at least 45 minutes between successive

observations at a station as a data gap. With our second approach (approach2), in the case of a data gap

between observations, our method considers the observation data in two subsets, the one before and the one

after the data gap while leaving the data gap empty.

0 100 200 300 400

0

0.5

1

1.5

2

VLBI observations at WETTZELL during 24th of August 2008 (CONT08)

total number of observations

observation time differences in hours

Fig. 1 Time differences in hours between successive observations at station WETTZELL during a daily CONT08 session,

08AUG24.

3.3 Approach3: Solution Intervals

Considering the Total Number of

Observations

We determine the estimation intervals depending on

the number of observations in our third approach (approach3). This approach ensures an equal redundancy

for each auxiliary parameter. Figures 2 and 3 show

how much the total number of observations supporting

an auxiliary parameter can vary, in the case of having

equally spaced time intervals for auxiliary parameter

estimation by the standard parameterization. The number and geometry of observations in equally spaced estimation intervals of a VLBI station, specific parameter

should be optimized when, for example, scheduling a

session or the estimation intervals for a specific parameter at each antenna should be optimized considering

the number and geometry of observations when analyzing a session.

IVS 2013 Annual Report
294 Tanır Kayıkc ̧ı and Teke

1000 1500 2000 2500

0

10

20

30

40

50

60

70

80

90

minutes elapsed since MJD 52583.00

number of observations per estimation interval

Estimated parameter: clock offsets

GILCREEK

KOKEE 

TSUKUB32

SESHAN25

URUMQI 

HOBART 26

Fig. 2 Total number of observations per clock offset estimation

interval: 60 minutes (as a standard parameterization) during session 02NOV05.

720 1080 1440 1800 2160 2520

0

50

100

150

200

250

300

350

400

450

minutes elapsed since MJD 52583.00

number of observations per estimation interval

Estimated parameter: troposphere north gradients

GILCREEK

KOKEE 

TSUKUB32

SESHAN25

URUMQI 

HOBART 26

Fig. 3 Total number of observations per troposphere gradient

offset estimation interval: 360 minutes (as a standard parameterization) during session 02NOV05.

4 Future Plans

Our preliminary results show that approach1 and approach3 provide better results for VLBI single session analysis than the standard parameterization. The

next step will be to practically assess the approach2.

Thereafter we will develop an optimized parameterization for auxiliary parameters in VLBI single session

least-squares analysis probably based on all three approaches.

Acknowledgements

We are thankful to all the Directing Board of IVS.

We are grateful to Karadeniz Technical University for

their financial support of KTU-GEOD IVS AC research activities. One of the co-authors, Emine TANIR

KAYIKC ̧ I, acknowledges Council of Higher Education

of Turkey (YOK) for the financial support of her research stay at GFZ.

References

1. J. Bohm, S. B  ̈ ohm, T. Nilsson, A. Pany, L. Plank, H. Spi-  ̈

cakova, K. Teke, H. Schuh, The new Vienna VLBI Software VieVS. Geodesy for Planet Earth, Proceedings of the

2009 IAG Symposium, Buenos Aires, Argentina, 31 August

— 4 September 2009, International Association of Geodesy

Symposia Series, 136, 1007–1011, edited by Steve Kenyon,

Maria Christina Pacino, Urs Marti.

2. R. Heinkelmann, J. Bohm, S. Bolotin, G. Engelhardt,  ̈

R. Haas, R. Lanotte, D. S. MacMillan, M. Negusini,

E. Skurikhina, O. Titov, H. Schuh, VLBI-derived troposphere parameters during CONT08, Journal of Geodesy, 85,

7, 377–393.

3. G. Petit, B. Luzum, IERS Conventions 2010, IERS Technical Note 36, Frankfurt am Main: Verlag des Bundesamts fur ̈

Kartographie und Geodasie, 179, ISBN 3-89888-989-6.  ̈

4. E. Tanır Kayıkc ̧ı, R. Heinkelmann, M. Karbon, T. Nilsson,

V. Raposo-Pulido, B. Soja, H. Schuh, Optimal size of constraints and interval lengths for VLBI auxiliary parameters,

IAG Scientific Assembly 2013, September 1-6, 2013, Potsdam.

IVS 2013 Annual Report
Analysis Center at National Institute of Information and

Communications Technology

Thomas Hobiger, Mamoru Sekido

Abstract This report summarizes the activities of the

Analysis Center at National Institute of Information

and Communications Technology (NICT) for 2013.

1 General Information

The NICT Analysis Center is operated by the spacetime standards group of NICT and is located in

Kashima, Ibaraki; its headquarters are in Koganei,

Tokyo. The Analysis Center focuses on the processing

of VLBI experiments which are related to NICT’s

research goals. Effort is spent on developing new

VLBI technology for time and frequency transfer, the

development of a modern multi-technique analysis

software package, prototyping of a compact VLBI

system, real-time EOP determination, and atmospheric

path delay studies.

2 Staff

Members who are contributing to the Analysis Center

at the NICT are listed below (in alphabetical order, with

working locations in parentheses):

• HOBIGER Thomas (Koganei, Tokyo): analysis

software development and atmospheric modeling

• ICHIKAWA Ryuichi (Koganei, Tokyo): coordination of activities

NICT, Japan

NICT Analysis Center

IVS 2013 Annual Report

• KONDO Tetsuro (Bangkok, Thailand and

Kashima): software correlator development

• SEKIDO Mamoru (Kashima): development of

VLBI systems, coordination of activities

3 Activities during the Past Year

3.1 Development of a Multi-technique

Space-geodetic Analysis Software

Package



	
















Fig. 1 The basic concept of c5++ allows processing of singleand multi-technique space geodetic observations by taking advantage of the usage of identical geophysical models (from [4]).

Driven by the need to update existing space geodetic analysis software and motivated by the demanding

goals of GGOS, a new analysis package named “c5++”

was developed. In contrast to the prior version, which

was written in Java, the new software was coded in

C++, which led to its naming. In doing so, the software

was designed to support combination of space geodetic data from Satellite Laser Ranging (SLR), VLBI,

295
296 Hobiger and Sekido

and Global Navigation Satellite System (GNSS) on

the observation level, but it also enables processing

of single-technique solutions. VLBI, GNSS, and SLR

modules (see Figure 1) share the same library, which

contains all geophysical models according to the latest

IERS Conventions. In addition, local tie information

can be included as virtual observations which relate between technique-specific reference points. The library

also provides interfaces to various space geodetic data

formats, enables reading/writing of SINEX files, and

supports all necessary mathematical functions for the

parameter adjustment process. c5++ does not have a

graphical user interface (GUI) but is called directly

from the command line and controlled via a configuration file. In the current version of c5++, a GaussMarkov model is used for the least-squares adjustment;

however, a Kalman filter is expected to be implemented

in the future as well.

c5++ was compared against other software packages [6] and is currently being used by the Geospatial

Information Authority of Japan (GSI) for ultra-rapid

determination of UT1 (see section 3.3 and [1]) on a

routine basis.

In contrast to combination of space geodetic results

where parameters are derived individually from each

technique, combination of all available space geodetic

observations on the observation level is expected to obtain more robust parameters. Outliers are less likely to

bias the solution as data from other techniques helps to

identify such data artifacts. Moreover, weaknesses of

one technique can be compensated by adding a second technique, improving geometrical coverage and

stabilizing the estimation of parameters which otherwise would depend on observations from that single

technique. In order to demonstrate the capability of the

software to combine data at the observation level, SLR

and VLBI observations were processed together, with

the goal of studying site motions at TIGO and revealing

the benefits of this approach [3]. In doing so, it could

be demonstrated that the coordinate time series before

the Chile 2011 earthquake derived from the combined

solution has less scatter than either of the two singletechnique solutions (see Figure 2).

In addition to local tie information, site-wise common parameters, i.e. troposphere and clocks, can be

estimated when microwave based techniques are combined on the observation level. [4] discusses how common parameters between GNSS and VLBI have to be

estimated and where biases/offsets need to be taken

into account. In order to test this concept, GPS and

VLBI data from the CONT11 campaign were utilized.

Obtained results show that the combination of space

geodetic data on the observation level leads to a consistent improvement of station position repeatability and

Earth orientation parameters as well as nuisance parameters like troposphere estimates. Furthermore, estimation of common parameters (troposphere or clocks)

at co-located sites helps to improve the solution further

and derive an utmost physically consistent model of the

concerned parameters (see details in [4]).

3.2 Frequency Transfer by Means of VLBI

Space geodetic techniques like GNSS have been

proven to be a useful tool for time and frequency

transfer purposes. Besides SLR, which is currently

tested under the name T2L2, VLBI could be another

space geodetic technique that can be utilized for

frequency transfer. In contrast to GNSS, VLBI does

not require any orbital information as it directly refers

to an inertial reference frame defined by the location

of the quasi stellar objects. As summarized by [7],

current VLBI systems can provide a frequency link

stability of about 2 x 10-15 @ 1d (ADEV). NICT’s

Space-Time Standards Laboratory is working on the

realization of a frequency transfer system based on the

principles of VLBI, whereas developments from the

upcoming geodetic VLBI2010 system are expected to

help to reach these goals. Our new analysis software

(see prior section) is ready to combine VLBI and

GNSS data on the observation level and thus support

the efforts of this project.

3.3 Ultra-rapid EOP Experiments

Geospatial Information Authority of Japan (GSI), Onsala Space Observatory, University of Tasmania, and

the Hartebeesthoek Radio Astronomy Observatory carried out several ultra-rapid EOP experiments which

were automatically analyzed with c5++. The analysis

process was adopted to handle automated ambiguity

resolution of a multi-baseline session and allow for a

robust estimation of the three EOP components. First

results demonstrated that all three EOPs can be estiIVS 2013 Annual Report
Analysis Center at NICT 297

 0

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Fig. 2 Histograms of the detrended coordinate time series of the single technique and combined solutions between January 1, 2008

and March 10, 2008 (i.e. the occurrence of the Chile 2010 earthquake) as discussed in [3].

mated from such a dedicated ultra-rapid observation

network. However, given the weak geometry of the

network and the rather low number of observations,

it is not clear whether the current observation strategy is sufficient for an accurate and reliable determination of all three EOP components. In addition to

these dedicated ultra-rapid experiments, GSI regularly

submits UT1 results automatically processed by c5++

from INT2 sessions on an operational basis (see [1] for

details on the processing strategy).

3.4 Ray-traced Troposphere Slant Delay

Correction for Space Geodesy

Kashima Ray-tracing Tools (KARAT) is a software

package that is capable of transforming numerical

weather model data sets to geodetic reference frames,

computing fast and accurate ray-traced slant delays,

and correcting geodetic data on the observation level.

A recent comparison [8] of troposphere delays from

space geodetic techniques, water vapor radiometers, and numerical weather models confirmed the

ray-tracing concept but made clear that one requires

accurate numerical weather models in order to compute a realistic refractivity field around space geodetic

instruments.

In addition, KARAT was extended to support

frequency dependency of the refractivity in the microwave domain following the Liebe model [5]. By

the use of this model, it is possible to compute the

complex refractivity based on atmosphere quantities

like pressure, temperature and relative humidity.

Using these new features, it was studied whether

modern space-geodetic microwave techniques (including VLBI2010 and higher dual-frequency VLBI

configurations) should be corrected for dispersive

IVS 2013 Annual Report
298 Hobiger and Sekido

troposphere delays. Although the frequency dependent

delay contribution appears to be of small order, one

has to consider that signals are propagating through

a range of a few kilometers of troposphere at high

elevations to hundredths of kilometers at low elevations. Thus, it has been investigated whether such

an effect has a magnitude above the noise floor of

modern space- geodetic instruments or whether it can

be safely neglected. The frequency dependent KARAT

module was also utilized for the development of a

semi-empirical correction model for the microwave

link of the Atomic Clock Ensemble in Space (ACES)

[2].

In addition, a model for optical (laser) techniques

is currently being implemented in order to support all

space geodetic techniques, including SLR.

4 Future Plans

For 2014, the plans of the Analysis Center at NICT include:

• Combination of multi-technique space-geodetic

data on the observation level with c5++

• Implementation of an interface for c5++, which allows reading and creation of OpenDB data

• Time and frequency transfer experiments by VLBI

and combination with other techniques like GNSS

or Two-Way Satellite Time and Frequency Transfer

(TWSTFT)

• Usage of multi-processors and multi-core processing platforms for the acceleration of space geodetic

applications

Acknowledgements

Parts of this work were supported by a Grant-in-Aid

for Young Scientists B (No.25740011). Design and implementation of c5++ was a huge effort, requiring the

participation and support of many individuals.

References

1. T. Hobiger, T. Otsubo, M. Sekido, T. Gotoh, T. Kubooka,

and H. Takiguchi, Fully automated VLBI analysis with c5++

for ultra-rapid determination of UT1, Earth, Planets, Space,

45, 2, 75–79, 2010.

2. T. Hobiger, D. Piester, and P. Baron, A correction model of

dispersive troposphere delays for the ACES microwave link,

Radio Science, 48(2), 131–142, 2013.

3. T. Hobiger, T. Otsubo, and M. Sekido, Combination of space

geodetic observations from SLR and VLBI on the observation level with c5++, Adv. in Space Research, 53(1), 119–

129, doi:10.1016/j.asr.2013.10.004, 2014.

4. T. Hobiger and T. Otsubo, Combination of GPS and VLBI

on the observation level during CONT11 - common parameters, ties and inter-technique biases, under review, 2014.

5. H.J. Liebe, MPM-An atmospheric millimeter-wave propagation model, Int. J. Infrared and Millimeter Waves, 10, 631-

650, 1989.

6. L. Plank, J. Boehm, and H. Schuh (2011), DeDeCC - Comparison of VLBI data analysis software - results; 12th IVS

Analysis Workshop, March 31, 2011, Bonn, Germany, 2011.

7. C. Rieck, R. Haas, R.T.K. Jaldehag, and J.M. Johansson,

VLBI time-transfer using CONT08 data, Proceedings of the

6th IVS General Meeting, 365-369, 2010.

8. K. Teke, T. Nilsson, J. Boehm, T. Hobiger, P. Steigenberger,

S. Garcia-Espada, R. Haas, and P. Willis, Troposphere delays from space geodetic techniques, water vapor radiometers, and numerical weather models over a series of continuous VLBI campaigns, Journal of Geodesy, 87(10-12),

981–1001, 2013.

IVS 2013 Annual Report
NMA Analysis Center 2013 Annual Report

Halfdan Pascal Kierulf, Ann-Silje Kirkvik, Per Helge Andersen

Abstract During the last few years, the Norwegian

Mapping Authority (NMA) has had a close cooperation with the Norwegian Defence Research Establishment (FFI) in the analysis of space geodetic data using the GEOSAT software. NMA has taken over the

full responsibility for the GEOSAT software. NMA

has been an Associate Analysis Center of IVS since

28 October 2010. NMA’s contributions to the IVS as

an Analysis Center focuses primarily on routine production of session-by-session unconstrained and consistent normal equations by GEOSAT as input to the

IVS combined solution. Several test solutions were uploaded to an IVS Combination Center during 2013. After the last improvements, the VLBI results produced

with GEOSAT are in good agreement with results from

the other VLBI Analysis Centers.

1 General Information

A number of co-located geodetic stations with more

than one observation technique were established. In

principle, all instruments at a given co-located station

move with the same velocity, and it should be possible to determine one set of coordinates and velocities

for each co-located site. In addition, a constant eccentricity vector from the reference point of the co-located

station to each of the individual phase centers of the colocated antennas is estimated using constraints in accordance with a priori information given by the ground

Norwegian Mapping Authority (NMA)

NMA Analysis Center

IVS 2013 Annual Report

surveys. One set of Earth orientation parameters (EOP)

can be estimated from all involved data types, while,

for instance, geocenter coordinates only can be estimated from satellite techniques and source positions

only can be estimated from VLBI. Combining the individual techniques at the observation level gives the possibility of taking the benefit of the strengths of the individual techniques and suppressing their weaknesses.

As one example, the present dominating error source

of VLBI is the water content of the atmosphere, which

must be estimated. The introduction of GPS data with a

common VLBI and GPS parameterization of the zenith

wet delay and atmospheric gradients will strengthen

the solution for the atmospheric parameters. The inclusion of SLR data, which is nearly independent of

water vapor, gives new information which will help in

the de-correlation of atmospheric and other solve-for

parameters and will lead to more accurate parameter

estimates.

These, and many more advantages with the

combination of independent and complementary

space geodetic data at the observation level, are fully

provided by the GEOSAT software developed by FFI

[1, 2]. GEOSAT is also useful for single technique

analysis. The VLBI module of GEOSAT is now further

developed by the NMA [4]. The goals are both to act as

an IVS Analysis Center delivering session-by-session

unconstrained and consistent normal equations to

the IVS Combination Centers and to provide quality

control for the different modules used in GEOSAT.

299
300 Kierulf et al.

2 Activities during the Past Year

During 2013, the NMA continued the work of making

the VLBI module of the GEOSAT software compatible

with other VLBI analysis software delivering results to

IVS. In addition, there is a lot of activity going on at

NMA to further develop the multi-technique software

GEOSAT (see the FFI TDC 2011 annual report). The

VLBI module has been upgraded to be compliant with

IERS Conventions 2010 [3], and some errors have been

eliminated — for instance errors in the SINEX files due

to misinterpretation of the format specification. NMA

submitted several smaller solutions to an IVS Combination Center, and adjustments were made in GEOSAT

based on the feedback from the IVS Combination Center. Finally, all R1 and R4 sessions from 2006 were

submitted to the IVS Combination Center, and the solutions were found to be comparable to that of the other

Analysis Centers (S. Bachmann, private communication). With this stabilized version of the software, 11

years (2003-2013) of R1 and R4 sessions were processed and are awaiting evaluation.

3 Future Plans

As soon as the 11-year test is compared with the individual solutions from the other ACs and the combined

solutions from IVS and the outcome of the comparisons are found to be satisfactory, NMA will implement

the GEOSAT VLBI processing in an automated processing chain. We will integrate the VLBI processing

into the NMA control center which already monitors

several geodetic applications. The NMA control center

is always manned during working hours.

In addition, a lot of effort is being put into passing

on the knowledge of Per Helge Andersen to the team

that will maintain GEOSAT in the future. This work

will continue in 2014 and has a very high priority. The

new GEOSAT team will consist of five to seven members, where a few members are only partially involved.

NMA will start to deliver unconstrained normal

equations in the SINEX format to the IVS Combination Center on a routine basis. As soon as this work is

satisfactory, NMA will apply for the status of a full IVS

Analysis Center.

Unlike most of the other VLBI analysis software

GEOSAT is based on a UD Kalman filter. This allows changing the stochastic behavior of the system.

NMA will test different stochastic parameters especially for the troposphere. Station and epoch dependent

stochastic parameters based on input from numerical

weather models and IGS tropospheric products will be

tested and evaluated. Tests of different models are also

planned — for instance, a comparison of results using

VMF1 and 3D ray tracing.

To produce VLBI solutions for IVS is the first part

of a larger strategic plan from NMA. The next step is

to include other geometric geodetic techniques (GNSS,

SLR, and DORIS) in a common solution where the

different techniques are combined at the observation

level. The long-term goal of this large effort is to also

include data from the gravity satellites GRACE and

GOCE and from altimeter satellites.

4 Staff

Ann-Silje Kirkvik - Master of Science (NMA),

Dr. Halfdan Pascal Kierulf - Research geodesist of

Norwegian Mapping Authority (NMA and UiO), Dr.

Per Helge Andersen - Research geodesist (NMA),

Dr. Ingrid Fausk - Research geodesist (NMA), Dr.

Oddgeir Kristiansen - Section Manager (NMA), Laila

Løvhøiden - Project leader (NMA).

References

1. Andersen, P. H., 1995. High-precision station positioning and satellite orbit determination. PhD Thesis,

NDRE/Publication 95/01094

2. Andersen, P. H., 2000. Multi-level arc combination with

stochastic parameters. Journal of Geodesy 74: 531-551 (doi:

10.1007/s001900000115)

3. Petit, G and Luzum B. (Eds.), 2010. IERS Conventions

(2010). (IERS Technical Note ; 36) Frankfurt am Main: Verlag des Bundesamts fur Kartographie und Geod  ̈ asie  ̈ , 179

pp., ISBN 3-89888-989-6

4. Kierulf, H.P., Andersen, P.-H., Boeckmann, S., and Kristiansen, O. 2010, VLBI Analysis with the Multi-technique

Software GEOSAT. IVS 2010 General Meeting Proceedings

pp. 207-211, edited by Dirk Behrend and Karen D. Baver

(NASA/CP-2010-215864)

IVS 2013 Annual Report
Paris Observatory (OPAR) Analysis Center

Sebastien Lambert, Christophe Barache, C  ́ esar Gattano  ́

Abstract We report on operational and research activities at the Paris Observatory VLBI Analysis Center

(OPAR) for calendar year 2013. Our achievements include the reanalysis of opa2013a and two research topics concerning the time stability of the ICRF2 axes and

the more accurate determination of the Solar system

acceleration.

1 Analysis Service

1.1 Operational Solutions

A reanalysis of the complete diurnal session database

was done (identified as opa2013a), and the resulting

EOP series and radio source catalogs were sent to the

IVS. This solution estimated EOP and rates as session

parameters, most of the station coordinates and the velocities as global parameters, and most of the sources’

coordinates as global parameters. Stations undergoing

strong nonlinear displacements were estimated as session parameters (e.g., TIGOCONC, TSUKUB32) instead of with the spline parameterization used in the

previous OPAR solutions. Troposphere and clock parameters were estimated every 20 minutes and 60 minutes, respectively, and gradients were estimated every

six hours (at all sites). Axis offsets were estimated as

global parameters for a list of 80 stations. We used

up-to-date geophysical and astronomical modeling to

compute the theoretical delay and partials, including

Observatoire de Paris/SYRTE – CNRS – UMPC – GRGS

OPAR Analysis Center

IVS 2013 Annual Report

the IAU 2006 nutation and precession, the Vienna mapping functions 1, the FES 2004 ocean loading model,

and the antenna thermal deformations as provided by

A. Nothnagel (2009, J. Geod., 83, 787). Constraints

were applied to the 295 ICRF2 defining sources (nonet rotation), and to 24 stations (no-net rotation and nonet translation of positions and velocities). We used the

latest version of the Calc/Solve geodetic VLBI analysis

software package.

Diurnal sessions were analyzed routinely within 24

hours after version 4 of the observation file was submitted to the IVS. The operational solution is aligned

to the opa2013a global solution. Unconstrained normal

equations relevant to EOP, rates, and station and source

coordinates were sent to the IVS in SINEX format for

combination in the framework of the IVS Analysis Coordinator’s task.

An operational solution analyzing Intensive sessions after 2006, started in 2011, was also continued

(opa2011i) together with corresponding SINEX files.

The solution opa2011i processed Intensive sessions in

order to produce UT1 consistent with VTRF 2008A,

ICRF2, and the IERS EOP 08 C 04 Earth orientation

data.

All the above products, except SINEX files, were

published on the OPAR Web site at

http://ivsopar.obspm.fr

together with exhaustive explanations and plots.

SINEX files were only sent to the data centers.

301
302 Lambert et al.

1.2 Other Products

Station and radio source coordinate time series were

updated. For each source, a page displays the time series and provides links to source information at various external databases (e.g., the French Virtual Observatory sofware package Aladin that permits a user to

get the optical counterpart of the VLBI quasars, or the

Bordeaux VLBI Image Database that gives the VLBI

structure).

The free core nutation (FCN) is a free oscillation of

the Earth’s figure axis in space due to the presence of

a liquid core rotation inside the viscoelastic mantle. Its

period is close to 430 days and is retrograde. Understanding the excitation of the FCN and its amplitude

and phase variations is still an open question, although

the community generally believes that the key resides

in improved atmospheric and oceanic circulation modeling at diurnal and subdiurnal frequencies. At OPAR,

we maintain an FCN model directly fitted to routinely

estimated nutation offsets (Figure 1). In addition to the

FCN, amplitudes and phases of a set of 42 prograde

and retrograde tidal waves are also fitted to the data.

These tidal terms are interpreted as small deficiencies

of the IAU 2000A nutation model and can be used together with the FCN model to build up a better a priori

nutation. Research is ongoing to identify some other

terms showing up in the residuals at the level of ten

microseconds of arc.

1980 1985 1990 1995 2000 2005 2010

−0.5

0

0.5

dX (mas)

1980 1985 1990 1995 2000 2005 2010 2015

−0.5

0

0.5

dY (mas)

Fig. 1 The amplitude of the free core nutation.

2 Research

2.1 Time Stability of the ICRF2 Axes

In Lambert (2013, A&A 553, 122), one assessed the

stability of the ICRF2 295 defining sources and of the

ICRF2 axes. This was achieved by deriving coordinate

time series of hundreds of quasars monitored by the

regular geodetic VLBI program of the IVS. The axis

stability was studied by constructing annual reference

frames based on the ICRF2 defining sources. The time

variable frame stability was obtained by computing the

deformation parameters that lead from one frame to the

next. The study showed that, although the astrometric

stability of some of the ICRF2 defining sources has

slightly degraded since 2009.2, the ensemble still constitutes a very stable frame of reference. The estimation

of the axis stability over 1979.6–2013.1 remains at the

same level as the one estimated in the ICRF work, i.e.,

on the order of 20 μas for each axis.

2.2 Improved VLBI Measurement of the

Solar System Acceleration

In a study by Titov & Lambert (2013, A&A 559,

95), the authors proposed new estimates of the secular aberration drift, which is mainly caused by the

rotation of the solar system about the Galactic center, based on up-to-date VLBI observations and improved method of outlier elimination. We fitted degree2 vector spherical harmonics to the extragalactic radio source proper motion field derived from geodetic

VLBI observations during 1979–2013. We paid particular attention to the outlier elimination procedure that

removes outliers from (i) radio source coordinate time

series and (ii) the proper motion sample. We obtain

more accurate values of the Solar system acceleration

than in our previous paper (Titov et al. 2011, A&A

529, 91). The acceleration vector is oriented towards

the Galactic center within ∼7

◦

. The component perpendicular to the Galactic plane is statistically insignificant. We show that an insufficient cleaning of the data

set can lead to strong variations in the dipole amplitude

and orientation and hence to statistically biased results

(see Figure 2).

IVS 2013 Annual Report
OPAR Analysis Center 303

0 60 120 180 240 300 360

−90

−60

−30

0

30

60

90

5 μas/yr

Right Ascension (°)

Declination (°)

DR

Fig. 2 The dipole pattern in the radiosource apparent proper motion field.

IVS 2013 Annual Report
Onsala Space Observatory – IVS Analysis Center Activities

during 2013

Rudiger Haas, Hans-Georg Scherneck, Johan L  ̈ ofgren, Tong Ning, Niko Kareinen  ̈

Abstract This report briefly summarizes the activities

of the IVS Analysis Center at the Onsala Space Observatory during 2013 and gives examples of results of

ongoing work.

1 General Information

We concentrate on research topics that are relevant for

space geodesy and geosciences. These research topics

are related to data observed with geodetic VLBI and

complementing techniques.

2 Activities during the Past Year

We worked primarily with the following topics:

• Automated reference point determination

• Simulations for the Onsala Twin Telescope project

• Analog vs. digital VLBI observations

• Coastal sea level observations with GNSS

• Ocean Tide Loading

• Gravimetry observations.

Chalmers University of Technology, Department of Earth and

Space Sciences, Onsala Space Observatory

Onsala Analysis Center

IVS 2013 Annual Report

3 Automated Reference Point

Determination

We developed a strategy to obtain an automated and

continual reference point determination of radio telescopes with sub-mm accuracy. This approach can be

used both in dedicated survey campaigns (stop-and-go

mode) as well as during ongoing VLBI sessions (continuous motion). The method was tested successfully

already in 2012, and the corresponding results were

published in [3].

4 Simulations for the Onsala Twin

Telescope Project

We performed simulations for the Onsala Twin Telescope (OTT) project, concerning both the actual location of the antennas and their local horizon masks as

well as future scheduling and use of the antennas.

Figure 1 depicts a digital elevation model of the

OTT plan that was submitted to the local authorities in

December 2013. Compared to a previously submitted

plan in 2012 [1] the antenna OTT1 has been moved towards the southwest. The local horizons for two antennas and for the combined OTT are shown in Figure 2.

Table 1 gives information on the horizon blockage at

different elevation limits.

The future use of the OTT was also studied by simulating possible observing schedules [4]. Several different scheduling strategies were tested with the VieVs

software. These simulations showed that the so-called

continuous mode approach with four radio sources at

a time gives the best results in terms of station po304
OSO – IVS Analysis Center 305

0 50 100 150 200 250 300 350 400 450 500

0

50

100

150

200

250

300

350

400

2

2

4

10

4

The sea

6

Wetland

8

10

6

18

2

8

20

OTT2

1416

OTT1

6

2

28

6

4

26

6

east (m)

4

4

2

2

4

6

30

4

32

4

6

The sea

12

24

6

2

2

16

8

25 m

1820

22

2

6

4

4

10

14

2

2

4

2

12

2

2 2

6

2

4

north (m)

The sea

Fig. 1 Digital elevation model of a selected area of the Onsala

Space Observatory, showing the location of the 25-m telescope,

and the planned Onsala Twin Telescope antennas, OTT1, and

OTT2 (plan of December 2013). These three telescopes are on

a small peninsula that is surrounded by the sea from southwest

to southeast and wetland in the east. In the north, there is a rocky

hill of more than 32-m height.

0 45 90 135 180 225 270 315 360

0

2.5

5

7.5

10

12.5

15

17.5

20

azimuth (deg)

elevation (deg)

OTT blocked > 5.0° : 7.5%

OTT blocked > 7.5° : 0%

OTT blocked > 10.0° : 0%

OTT1

OTT2

OTT

Fig. 2 Horizon masks for the individual twin telescopes, OTT1

(dashed line, red) and OTT2 (dashed-dotted line, blue), and combined for both OTT antennas together (solid line, black), as seen

from the lower edge of the prime reflectors. The OTT telescopes

see each other (at about 30◦and 240◦azimuth), and they see the

25-m telescope at about 210◦and 290◦azimuth. However, the

common horizon is completely free above 7.5◦and only blocked

by 7.5 % at elevation 5◦.

sitions and EOP. However, the continuous mode approach with two radio sources at a time strategy appeared to be superior in terms of accuracy of tropospheric parameters. Further investigations are necessary.

Table 1 Horizon blockage at different elevation limits.

antenna blocking

> 5

◦ > 10◦ > 15◦

OTT1 18.1 % 9.4 % 5.0 %

OTT2 22.5 % 5.8 % 0 %

OTT 7.5 % 0 % 0 %

25 m 14.7 % 4.7 % 0 %

5 Analog vs. Digital VLBI Observations

About 2/3 of the geodetic VLBI sessions performed in

2013 at Onsala were observed both with the old analog

Mark IV rack and the new digital DBBC. Zero-baseline

tests were performed using the DiFX software correlator at Onsala and at the Bonn correlator. Figure 3 depicts as an example the zero-baseline correlation for

one scan of the experiment R1567.

The Bonn correlator also prepared for several of

these parallely recorded experiment databases that inMk4/DiFX fourfit 3.8 rev 756 0800+618.wpscuq, 007-1714, WX

ONSADBBC - ONSALA60, fgroup X, pol RR

9

70659.6

93.440

9598.447

-53.6

0.0e+00

-1.926363

-0.000063

0.000008

 0.00

8212.9900

1.280

R1567

16383

2013:007

171426.28

171559.72

171512.00

2013:014:102917

2013:015:103659

2012:201:081500

08h05m18.1796s

+61 ̊44’23.700"

Fringe quality

SNR

Int time

Amp

Phase

PFD

Delays (us)

SBD

MBD

Fringe rate (Hz)

Ion TEC 

Ref freq (MHz)

AP (sec)

Exp.

Exper #

Yr:day

Start

Stop

FRT

Corr/FF/build

RA & Dec (J2000)

Amp. and Phase vs. time for each freq., 25 segs, 3 APs / seg (3.84 sec / seg.), time ticks 5 sec

U

Validity

L

WX

8212.99 Freq (MHz)

-49.9 Phase

10569.4 Ampl.

451.1 Sbd box

U/L 73/73 APs used

W 5010 PC freqs

X 5010 PC freqs

W:X 61:136 PC phase

W:X 0:0 Manl PC

W 24 PC amp

X 25

X00U,X01L Chan ids W

X00U,X01L Chan ids X

8252.99

-59.5

9584.9

451.2

73/0

5010

5010

168:133

0:0

22

24

X02U

X02U

8352.99

-54.4

11389.4

451.1

73/0

5010

5010

-57:-148

0:0

23

26

X03U

X03U

8512.99

-57.3

10459.7

451.0

73/0

5010

5010

48:-78

0:0

22

24

X04U

X04U

8732.99

-55.0

8945.4

451.7

73/0

5010

5010

77:-88

0:0

20

22

X05U

X05U

8852.99

-49.0

9344.4

451.7

73/0

5010

5010

-42:-47

0:0

21

23

X06U

X06U

8912.99

-47.3

9265.8

451.9

73/0

5010

5010

-114:50

0:0

21

22

X07U

Tracks

X07U

Tracks

8932.99

-57.7

8052.0

451.7

73/73

5010

5010

-141:2

0:0

22

22

X08U,X09L

X08U,X09L

All

-53.6

9623.2

451.4

Group delay (usec)

Sband delay (usec)

Phase delay (usec)

Delay rate (us/s)

Total phase (deg)

-8.23964039918E-05

-1.92638223394E+00

-3.78093981831E-05

3.02254897572E-10

-111.8

Apriori delay (usec)

Apriori clock (usec)

Apriori clockrate (us/s)

Apriori rate (us/s)

Apriori accel (us/s/s)

-1.96744755904E-05

0.0000000E+00

0.0000000E+00

-7.97208722291E-10

2.18162936353E-13

Resid mbdelay (usec)

Resid sbdelay (usec)

Resid phdelay (usec)

Resid rate (us/s)

Resid phase (deg)

-6.27219E-05

-1.92636E+00

-1.81349E-05

1.09946E-09

-53.6

+/-

+/-

+/-

+/-

+/-

8.0E-09

7.0E-07

4.0E-10

1.0E-11

0.0

RMS Theor. Amplitude 9598.447 +/- 0.136 Pcal mode: NORMAL, NORMAL Pcal period (AP’s) 9999, 9999

ph/seg (deg) 0.1 0.0 Search (256X256) 9225.956 Pcal rate: -9.549E-09, -9.393E-09 (us/s) sb window (us) -16.000 16.000

amp/seg (%) 0.0 0.0 Interp. 9225.956 Bits/sample: 1 SampCntNorm: disabled mb window (us) -0.025 0.025

ph/frq (deg) 4.2 0.0 Inc. seg. avg. 9598.457 Sample rate(MSamp/s): 16 dr window (ns/s) -0.048 0.048

amp/frq (%) 10.3 0.0 Inc. frq. avg. 9623.221 Data rate(Mb/s): 160 nlags: 512 t_cohere infinite ion window (TEC) 0.00 0.00

W: az 39.0 el 42.9 pa -45.8 X: az 39.0 el 42.9 pa -45.9 u,v (fr/asec) 0.000 -0.000 iterative interpolator

Control file: ../cf_1234 Input file: /Exps/r1567/1234/007-1714/WX..wpscuq Output file: Suppressed by test mode

Fig. 3 Fringe plot for a zero-baseline test for an X-band observation during session R1567.

IVS 2013 Annual Report
306 Haas et al.

clude Onsala both as an analogue station (On) and as

a digital station (Od). We analyzed several of these

databases, and our preliminary results are that there are

no significant effects on the geodetic results, in particular on the earth orientation parameters, if either the

analog or digital data are used for the data analysis.

Further investigations with a larger set of databases are

necessary.

6 Coastal Sea Level Observations with

GNSS

We used the GNSS-based tide gauge installation at the

observatory to derive the local sea level and its variation using reflected GNSS signals.

Besides using phase-delay analysis of the data

recorded with the special dual-antenna GNSS tide

gauge installation at Onsala, we also used signal-tonoise-ratio (SNR) analysis of the data observed only

by the upward-looking GNSS antenna [2]. The study

proved that this SNR analysis method can be applied

to coastal single-antenna installations.

A comparison of relative sea levels derived from

the GNSS tide gauge, a co-located pressure-based tide

gauge, and a recently installed co-located tide gauge

based on a pneumatic sensor is shown for the month

of September in Figure 4. The tide gauge based on the

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

−0.5

0

0.5

1

1.5

Day in September 2013

Relative sea level (m)

Bubbler Pressure GNSS

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

−400

−200

0

200

400

600

Relative sea level differences (mm)

Day in September 2013

Pressure − Bubbler

GNSS − Bubbler

Standard deviation: 13 mm

Standard deviation: 46 mm

−600

−400

−200

0

200

Fig. 4 Top: Relative sea levels derived from the pneumatic sensor (“bubbler”), a pressure sensor, and the GNNS tide gauge, for

September 2013. The data are offset from each other to improve

readability. Bottom: Relative sea level differences with respect

to the bubbler.

pneumatic sensor (the “bubbler”) has according to the

manufacturer a measurement uncertainty of ±3 mm.

The two other techniques (pressure sensor and GNSS

tide gauge) result in an agreement with the bubbler on

the order of 13 mm and 46 mm (standard deviation after bias removal), respectively.

7 Ocean Tide Loading

The Automatic Ocean Tide Loading service was operated throughout the year. It is heavily used by the international scientific community.

8 Gravimetry Observations

Since January 2013 the superconducting gravimeter in

the gravity laboratory at the Onsala Space Observatory

communicates one-second data to the world. The

instantaneous measurements are presented on the

webpage http://holt.oso.chalmers.se/

hgs/SCG/monitor-plot.html. The presented

values are reduced for air pressure and astronomical

tides and shown in the largest diagram. A summary of

the last 30 days and a spectrogram of the short-period

noise are also shown. A link makes numeric data

available for download with a latency of less than two

minutes; other links allow the identification of seismic

events and the causes of microseismic noises (mostly

remote action due to high waves in specific areas of

the North Atlantic region).

9 Future Plans

The IVS Analysis Center at the Onsala Space Observatory will continue its efforts to work on specific topics relevant to space geodesy and geosciences. For the

future we plan to intensify our activities, in particular

concerning horizontal gradients in the atmosphere using VLBI, GNSS, and radiometers. A special focus for

the coming years will be work related to the Onsala

Twin Telescope project.

IVS 2013 Annual Report
OSO – IVS Analysis Center 307

References

1. Haas R. The Onsala Twin Telescope Project. Reports of the

Finnish Geodetic Institute, Proceedings of the 21st Meeting

of the European VLBI Group for Geodesy and Astronomy,

Ed. by N. Zubko and M. Poutanen, 2013:1 (1), 61–65, 2013.

2. Larson K., Lofgren J., Haas R. Coastal Sea Level Measure-  ̈

ments Using a Single Geodetic GPS Receiver. Advances in

Space Research, 51(8), 1301–1310, 2013.

3. Losler M., Haas R., Eschelbach C. Automated and continual  ̈

determination of radio telescope reference points with submm accuracy: results from a campaign at the Onsala Space

Observatory. Journal of Geodesy, 87(8), 791–804, 2013.

4. Schonberger C. Simulations of VLBI observations  ̈

with the Onsala Twin Telescope. Master of Science Thesis, Chalmers University of Technology,

http://publications.lib.chalmers.se/

records/fulltext/185857/185857.pdf, 2013.

IVS 2013 Annual Report
PMD Analysis Center 2013 Annual Report

Vincenza Tornatore

Abstract This report summarizes the activities of the

Politecnico di Milano (PMD) IVS Analysis Center during the year 2013 and outlines the planned aspects

of work for 2014. The main focuses in 2013 were in

the framework of the IAG WG 1.4.2 on Co-location

on Earth and in Space for the determination of the

Celestial Reference Frame. Studies carried out concern e.g. simulations for some European VLBI antennas performed to investigate if the VLBI phase referencing technique can be used for precise determination of GNSS state vectors. Furthermore, investigations

into possible deformations introduced by the change to

ICRF2 [1] were also made for the processing of 24-

hour observational sessions.

1 General Information

Throughout 2013, Milan University of Technology

(Politecnico di Milano) celebrated the 150th anniversary of its establishment with several events, see

Figure 1 and Figure 2; some of these events are listed

in [2].

The department, supporting activities of the PMD

IVS Analysis Center, changed since January 2013. The

new one is called Department of Civil and Environmental Engineering (DICA) [3]. Therefore the name

of the Analysis center PMD stands for Politecnico di

Milano Dica now. This new department belongs, like

the previous one (called Diiar), to Milan University of

Politecnico di Milano, Department of Civil and Environmental

Engineering (DICA), Geodesy and Geomatic area

PMD Analysis Center

IVS 2013 Annual Report

Fig. 1 2013 marked the 150th year of the establishment of the

Politecnico di Milano.

Fig. 2 People celebrating the 150th anniversary of the Politecnico di Milano.

Technology. It deals with plentiful research areas in

civil and environmental engineering, enhancing an integrated approach among them.

308
PMD 2013 Report 309

The research area called Geodesy and Geomatic

hosts and operates the PMD IVS AC and IGeS (International Geoid Service), an official Service of the

International Association of Geodesy (IAG), see [4].

PMD started officially its activity in October 2010 [5].

DICA supplies hardware equipment, software licenses

and assistance, and the personnel necessary to manage

it.

2 Staff

During 2013, the following persons contributed to the

PMD activity:

1. Vincenza Tornatore — team coordinator, project

developer, data analysis;

2. Cinzia Vajani — software maintenance;

3. Daniele Passoni — data processing.

3 Current Status and Activities

During 2013, the main activities developed by the

PMD IVS Analysis Center were addressed to studying

if the observing technique called phase referencing

(largely used for high precision VLBI astrometry, see

e.g. [6] and [7]) could be applied to observing GNSS

satellites with the aim of improving the precision of

the determination of the satellite state vector and of

obtaining satellite positions directly in ICRF. It is well

known that the strong power emitted by the satellites

compared to the very low emission of natural radio

sources (calibrators) could represent a limiting factor,

because the satellite signal can be easily detected

through near sidelobes when observing, at the same

satellite frequency, the natural calibrator in the main

beam.

To get an indication of this problem, some preliminary investigations were carried out. We ran some simulations, in collaboration with the University of Milan

(Physics Department), using GRASP (General Reflector antenna Analysis Software Package) v.10, to assess

the relative power contribution of satellites in the near

sidelobes when observing in L-band a natural calibrator in the main beam. For each examined station, we

evaluated the minimum angular distance between the

satellite and the calibrator to avoid near-sidelobe straylight contamination from the satellite emission when

the calibrator is tracked.

Three European VLBI antennas, Medicina, Noto

and Onsala85, were considered. All three antennas

have a Cassegrain configuration with a parabolic

primary dish and a hyperbolic secondary dish. The

L-band receiver is mounted at the primary focus only

at Medicina, while for Noto and Onsala85 it is at

the secondary focus. Figure 3 shows the GRASP 3D

model of the optics of the three antennas, while the

corresponding beam patterns are shown in Figure 4.

Detailed results and discussions on this work have

been published in [8]. To briefly summarize, we can

write that the key role in avoiding calibrator signal contamination due to a strong satellite signal seems to be

played by the telescope optical configuration, with better results obtained for Medicina (with the L-band receiver at the primary focus), than for Noto and Onsala85 (with the L-band receiver at the secondary focus).

During 2013, another subject tackled by PMD AC

concerned investigations into possible deformations introduced by the change to ICRF2. In tight collaboration

with the VIE IVS Analysis Center and the PUL IVS

AC, 27 years of suitable VLBI experiments, measured

in 24-hour sessions, were analyzed. The starting year

was 1984. IERS (International Earth Rotation and Reference Systems Service) [9] and IVS conventions on

VLBI data [10] were followed in the data processing.

Session-wise solutions were computed with the Vienna

VLBI Software VieVS [11]. Results are going to be

published, after an in-depth analysis and complementary studies are completed.

4 Future Plans

In 2014, the work of the PMD Analysis Center will

focus on the following aspects:

• Co-location on Earth and in Space for the determination of the Celestial Reference Frame.

• Investigation into dedicated algorithms for tropospheric parameter estimation, particularly

addressed to a territory not very broad, such as the

Italian region.

• Continuation of investigations into ICRF2.

IVS 2013 Annual Report
310 Tornatore

Fig. 3 VLBI radio telescope optics simulated with GRASP, in

the order from top to bottom: Medicina, Noto, and Onsala85.

Acknowledgements

The author wishes to thank IRA/INAF, Istituto di Radioastronomia, Italy (S. Mariotti, G. Nicotra, and F.

Schilliro), and Onsala85 radio telescope, operated by `

Fig. 4 VLBI radio telescope optics simulated with GRASP, in

the order from top to bottom: Medicina, Noto, and Onsala85.

the Swedish National Facility for Radio Astronomy,

Sweden (M. Lundqvist and M. Pantaleev), for having provided the values about antenna dish geometry

and feed characteristics used to make simulations with

GRASP.

IVS 2013 Annual Report
PMD 2013 Report 311

References

1. IERS technical note 35, The second realization of the international celestial reference frame by very long baseline interferometry, Fey A.L., Gordon D., Jacobs C.S. (eds) Verlag

des Bundesamts fur Kartographie und Geod  ̈ asie, Frankfurt  ̈

am Main, 2009 (http://www.iers.org/TN35).

2. http://www.150.polimi.it.

3. http://www.dica.polimi.it/en/.

4. http://www.iges.polimi.it/.

5. Tornatore V., New Associate Analysis Center Established

at PMD, in International VLBI Service for Geodesy and

Astrometry 2010 Annual Report, NASA/TP-2011-215880,

Behrend D. and Baver K.D. (eds), 244-246, 2011.

6. Lane B. F.and Muterspaugh M.W., Phase referencing and

narrow-angle astrometry in current and future interferometers in Proceedings of SPIE, V. 5491, N.1 Traub W.A. ed,

SPIE Bellingham, WA, 47-55, 2004.

7. Asaki Y., Sudou H., Kono Y., Doi A., Dotson R., Pradel N.,

Murata Y., Mochizuki N., Edwards P.G., Sasao T., Fomalont E.B. Verification of the Effectiveness of VSOP-2 Phase

Referencing with a Newly Developed Simulation Tool, ARIS,

Publ. Astron. Soc. Japan, 59, 397, 2007.

8. Tornatore V., Mennella A. On the possibility of using VLBI

phase referencing to observe GNSS satellites, in: 21th European VLBI for Geodesy and Astrometry (EVGA) Working

Meeting Proceedings, Zubko N., Poutanen M., (eds), 227-

231, 2013.

9. Petit G., Luzum B. (eds.), IERS Conventions (2010), IERS

Technical Note 36, Frankfurt am Main: Verlag des Bundesamts fur Kartographie und Geod  ̈ asie, 2010.  ̈

10. Nothnagel A. Conventions on thermal expansion modeling

of radio telescopes for geodetic and astrometric VLBI, in

Journal of Geodesy, 83, 787—792, 2008.

11. Bohm J., B  ̈ ohm S., Nilsson T., Pany A., Plank L., Spi-  ̈

cakova H., Teke K., Schuh H. The new Vienna VLBI

Software VieVS in IAG Symposium 139, Kenyon S., Pacino M.C., Marti U. (eds), 1007-1012, 2012.

IVS 2013 Annual Report
Pulkovo IVS Analysis Center (PUL) 2013 Annual Report

Zinovy Malkin, Yulia Sokolova

Abstract This report briefly presents the PUL IVS

Analysis Center activities during 2013 and plans for

the coming year. The main topics of the investigations

of the PUL staff in that period were ICRF related studies, computation and analysis of EOP series, celestial

pole offset (CPO) and free core nutation (FCN) modeling, and VLBI2010 related issues.

1 General Information

The PUL IVS Analysis Center was organized in

September 2006. It is located at and sponsored by

the Pulkovo Observatory of the Russian Academy

of Sciences. It is a part of the Pulkovo EOP and

Reference Systems Analysis Center (PERSAC) [1].

The main topics of our IVS related activity are:

• Improvement of the International Celestial Reference Frame (ICRF).

• Computation and analysis of the Earth orientation

parameters (EOP) from Intensives and 24-hour IVS

sessions.

• Analysis of EOP and position time series.

• Modeling of the celestial pole offset (CPO) and free

core nutation (FCN).

• Comparison of VLBI products, primarily EOP,

with results of other space geodesy techniques.

• Computation and analysis of observation statistics.

The PUL Analysis Center Web page [2] is supported. It contains the following sections:

Pulkovo Observatory

Pulkovo Analysis Center (PUL)

IVS 2013 Annual Report

• General Information on the PUL Analysis Center.

Includes brief history, activity overview, and a scientific staff list.

• VLBI data analysis. Includes results of VLBI data

analysis, such as UT1 Intensive series, CPO/FCN

series, and mean Pole coordinates. These data are

updated daily.

• OCARS catalog. Includes the latest version of the

catalog of optical characteristics of astrometric radio sources (OCARS) [3]. The catalog is continually updated as new information becomes available.

• Approaches and occultations. Includes tables for

forthcoming mutual events of planets and astrometric radio sources, such as close angular approaches

and occultations for the period until 2050 [4].

• PUL members’ publications and presentations.

• VLBI technology overview.

• Links to the VLBI World. Includes links to (primarily geodetic and astrometric) VLBI coordinating bodies, stations, analysis centers, software, etc.

• Contact information.

2 Staff

In 2013 the following persons contributed to the PUL

activity:

1. Zinovy Malkin (70%) — team coordinator, EOP

and CRF analyst;

2. Natalia Miller (5%) — EOP analyst; and

3. Yulia Sokolova (100%) — CRF analyst.

312
Pulkovo Analysis Center (PUL) 313

3 Activities and Results

The main activities and results of the PUL IVS Analysis Center during 2013 included:

• ICRF related research. The main directions of this

activity were comparison and combination of radio

source catalogs and investigation of their stochastic

and systematic errors. In 2013, the following results

were obtained:

– A new Pulkovo combined catalog was computed [5]. Using CRF realizations from eight

IVS Analysis Centers (aus, bkg, cgs, gsf, igg,

opa, sha, and usn), we computed two combined

catalogs: PUL (2013) C01 and PUL (2013)

C02. The method used generally follows our

previous work [6]. Besides using more data,

several developments were realized as compared with the previous version of the Pulkovo

combined catalog of 2007 [6]. The PUL (2013)

C01 catalog is constructed in the ICRF2 [7]

system and is aimed at improving ICRF2

random errors, while the final, PUL (2013) C02

catalog is constructed in an independent system

and thus provides both stochastic and systematic improvement of the ICRF2. Comparison

of the Pulkovo combined catalog with ICRF2

gives evidence of ICRF2 systematic errors at a

level of 15–20 μas.

– Impact of the correlation information on the results of determination of the angles of mutual

orientation between catalogs was investigated

[8]. This work continues the work of Jacobs

et al. [9]. Test computations were performed

with nine catalogs computed in eight centers of

analysis of the VLBI observations. The mutual

orientation between these CRF realizations was

computed with three methods of accounting for

the correlation information: using the position

errors only, using only the RA/DE correlations

reported in radio source position catalogs in the

IERS format, and using the full correlation matrix. Only two of these catalogs, igg and gsf,

were provided together with full covariance matrices (thanks to the authors of these catalogs

who made them available for our work); seven

other catalogs were published with RA/DE correlations only. Our analysis has shown that using the RA/DE correlations only slightly influences the computed rotational angles, whereas

using the full correlation matrices leads to substantial change in the orientation parameters between the compared catalogs.

– A new approach to estimation of the stochastic errors of radio source position catalogs was

proposed [10]. It is based on the three-corneredhat technique, extended to the N-cornered-hat

technique. A key point of the method is a new

approach to computation of the correlations between the compared catalogs. As an additional

refinement, the concept of weighted correlation

coefficient was introduced. This technique was

applied to nine recently published radio source

position catalogs. We also found large systematic differences between catalogs that significantly impact determination of their stochastic

errors.

– A study was performed aimed at a search for

an optimal strategy for using limited observational resources in the southern hemisphere

to improve ICRF in the band δ < −40◦

[11].

We investigated the possibility of increasing

the number of observations of existing and

prospective southern ICRF radio sources by

inclusion of more such sources in the regular

IVS sessions like R1 and R4. With Monte

Carlo simulations, we tested the influence of

adding supplementary southern sources to the

IVS R1541 (12JUL09XA) session on EOP

and baseline length repeatability. We found

that adding more observations of southern

sources to the standard schedule causes a slight

degradation of some geodetic products and a

slight improvement of others, depending on

the number of added southern sources. Similar results were obtained for the IVS R1591

(13JUN24XA) session. Generally, it was shown

that it is possible to increase the number of

observations of southern sources without loss

of the overall accuracy of geodetic products.

– The OCARS catalog [3] has been supported

since 2008. The catalog provides redshift information, as well as visual and NIR magnitudes.

The improvements made in 2013 include addition of new sources and new measurements of

redshift and magnitude. The current basic statistics of the catalog are given in Table 1.

IVS 2013 Annual Report
314 Malkin and Sokolova

Table 1 Current basic statistics of the OCARS catalog.

All sources ICRF2 sources ICRF2 defining

Sources 8246 3414 295

Sources with known redshift 4353 (52.8%) 2249 (65.9%) 261 (88.5%)

Sources with known magnitude 5395 (65.4%) 2618 (76.7%) 285 (96.6%)

• CPO and FCN related research. The main activities

and results in 2013 were the following:

– Two CPO and two FCN series were updated

daily and are available at the PERSAC Web

page [1].

– FCN amplitude and phase variations derived

from VLBI observations were investigated.

Comparison of the epochs of the changes in the

FCN amplitude and phase with the epochs of

the geomagnetic jerks (GMJs) indicated that

the observed extremes in the FCN amplitude

and phase variations were closely related to the

GMJ epochs. In particular, the FCN amplitude

begins to grow one to three years after the

GMJs. Thus, processes that cause GMJs are

assumed to be sources of FCN excitation [13].

– Several VLBI-derived CPO time series were analyzed with the goal of detecting the Free Inner Core Nutation (FICN) [14]. The series were

investigated by means of spectral and wavelet

analysis. It was shown that there are several periodic signals with close amplitude around the

expected FICN period without a prevailing one,

which can be associated with the FICN. So, it

seems to be necessary to improve the theoretical

estimates of the FICN period to make searching

for it in the observational series more promising.

– A study was made to investigate optimal CPO

modelling for operational determination of UT1

from hourly sessions with the Quasar VLBI

network (Institute of Applied Astronomy). It

was found that the systematic differences between the UT1 estimates computed with different models (trend and seasonal terms) are at a

level of 1-3 μs. On the other hand, the formal

error of the UT1 estimates practically does not

depend on the CPO model used [12].

• Studies in the framework of the IAG SC 1.4 activity on investigation of the mutual impact of celestial and terrestrial reference frames and impact of

astronomical and geophysical modelling on ICRF.

A study was performed to investigate the impact

of seasonal station movement on the UT1 Intensives results [15]. It was found that a significant

annual term is present in the time series for most

stations, and its amplitude can reach 8 mm in the

height component and 2 mm in the horizontal components. However, the annual signals found in the

displacements of the co-located VLBI and GPS stations at some sites differ substantially in amplitude

and phase. The semiannual harmonics are relatively

small and unstable, and for most stations no prevailing signal was found in the corresponding frequency band. Then two UT1 Intensives series were

computed with and without including the seasonal

term found in the previous step in the station movement model. Comparison of these series has shown

that neglecting the seasonal station position variations can cause a systematic error in UT1 estimates,

which can exceed 1 μs, depending on the observing

program.

• Operational data processing of IVS Intensive sessions in automated mode and submission of results

to IVS was continued. The UT1 time series is available at IVS Data Centers and at the PERSAC Web

page [1].

• The PUL archive of VLBI data and products

obtained in the framework of IVS activity is

supported. At present, all available databases and

corresponding NGS cards for 1979-2013 are stored

(about 9.4 million observations) along with the

main IVS and IERS products. These archives are

continually updated as new databases become

available.

• Development of algorithms and software for data

processing and analysis continued. The results

of two studies were published in 2013. The first

paper deals with improvement of the application

of the Allan variance technique to astronomical

and geodetic time series with unevenly weighted

measurements [16]. Modifications of the standard

AVAR definition for unevenly spaced and multidimensional series were proven to be an effective

IVS 2013 Annual Report
Pulkovo Analysis Center (PUL) 315

tool for data processing. In the second study, the

problem of computation of the uncertainty of

a weighted mean of several measurements was

considered [17]. It was found that two classical approaches have serious shortcomings when applied

to real data. Therefore, a combined estimate for the

uncertainty of the weighted mean was proposed

and successfully tested.

• PUL staff members participated in activities of several IERS, IAG, and IVS projects, committees, and

working groups.

4 Future Plans

Plans for the coming year include:

• Continuing VLBI related studies.

• Continuing UT1 Intensive data processing.

• Continuing OCARS catalog support.

• Continuing with development of algorithms and

software for data processing.

• Continuing support of the PUL archives of data and

products.

References

1. http://www.gao.spb.ru/english/as/persac/index.htm

2. http://www.gao.spb.ru/english/as/ac vlbi/

3. http://www.gao.spb.ru/english/as/ac vlbi/ocars.txt

4. http://www.gao.spb.ru/english/as/ac vlbi/

occultations approaches.pdf

5. Sokolova Yu, Malkin Z. Pulkovo combined catalog of radio

source coordinates PUL 2013. Astronomy Letters, 2013, accepted.

6. Sokolova Ju., Malkin Z. On comparison and combination of

catalogs of radio source positions. Astron. Astrophys., 2007,

474, 665–670.

7. Ma C., E. F. Arias, G. Bianco, D. A. Boboltz, S. L. Bolotin, P.

Charlot, G. Engelhardt, A. L. Fey, R. A. Gaume, A. M. Gontier, R. Heinkelmann, C. S. Jacobs, S. Kurdubov, S. B. Lambert, Z. M. Malkin, A. Nothnagel, L. Petrov, E. Skurikhina,

J. R. Sokolova, J. Souchay, O. J. Sovers, V. Tesmer, O. A.

Titov, G. Wang, V. E. Zharov, C. Barache, S. Boeckmann,

A. Collioud, J. M. Gipson, D. Gordon, S. O. Lytvyn, D. S.

MacMillan, R. Ojha. The Second Realization of the International Celestial Reference Frame by Very Long Baseline

Interferometry. IERS Technical Note No. 35, A. L. Fey, D.

Gordon, C. S. Jacobs (Eds.), Verlag des Bundesamts fuer Kartographie und Geodaesie, Frankfurt am Main, 2009.

8. Sokolova Ju. R., Malkin Z. M. On impact of the correlation

information on the orientation parameters between celestial

reference frames. Vestnik of the St. Petersburg State University, Ser. 1, No. 4, 146–151, 2013. (in Russian)

9. Jacobs C. S., Heflin M. B., Lanyi G. E., Sovers O. J., Steppe

J. A. Rotational Alignment Altered by Source Position Correlations. In: IVS 2010 General Meeting Proc, Eds. D. Behrend,

K.D. Baver, NASA/CP-2010-215864, 305–309, 2010.

10. Malkin Z. A new approach to the assessment of stochastic errors of radio source position catalogues. Astron. Astrophys., v. 558, A29, 2013.

11. Malkin Z., Sun J., Boehm J., Boehm S., Krasna H. Searching for an Optimal Strategy to Intensify Observations of the

Southern ICRF sources in the framework of the regular IVS

observing programs. In: Proc. 21st Meeting of the EVGA,

Eds. N. Zubko, M. Poutanen, Rep. Finn. Geod. Inst., Vol.

2013:1, 199–203. ISBN: 978-951-711-296-3, 2013.

12. Malkin Z. M., Skurikhina E. A. Dependence of the rapid

UT1 results obtained from the VLBI network “Quasar” on

nutation model. Proc. of the All-Russian Astrometry Conference Pulkovo-2013, Izvestiya GAO, No. 220, St. Petersburg:

Pulkovo Observatory, 119–124, 2013. (in Russian)

13. Malkin Z. Free core nutation and geomagnetic jerks. J. of

Geodynamics, v. 72, 53–58, 2013.

14. Malkin Z. M. On the observability of the free inner core

nutation. Proc. of the All-Russian Astrometry Conference

Pulkovo-2013, Izvestiya GAO, No. 220, St. Petersburg:

Pulkovo Observatory, 115–118, 2013. (in Russian)

15. Malkin Z. Impact of seasonal station motions on VLBI UT1

Intensives results. J. of Geodesy, v. 87, 505–514, 2013. DOI:

10.1007/s00190-013-0624-5

16. Malkin Z. Using modified Allan variance for time series

analysis. In: Reference Frames for Applications in Geosciences, Z. Altamimi, X. Collilieux (eds.), IAG Symposia,

v. 138, 271–276, 2013. DOI: 10.1007/978-3-642-32998-2 39

17. Malkin Z. M. On the Calculation of Mean-Weighted Value

in Astronomy. Astronomy Reports, v. 57, 882–887, 2013.

DOI: 10.1134/S1063772913110048

IVS 2013 Annual Report
SAI VLBI Analysis Center 2013 Annual Report

Vladimir Zharov

Abstract This report presents an overview of the SAI

VLBI Analysis Center activities during 2013 and the

plans for 2014. The AC SAI analyzes all IVS sessions

for computations of the Earth orientation parameters

(EOP) and time series of the ICRF source positions and

performs research and software development aimed at

improving the VLBI technique.

1 General Information

The SAI VLBI Analysis Center is located at Sternberg

State Astronomical Institute of Lomonosov Moscow

State University in Moscow, Russia. The Analysis Center participates in geodetic and astrometric VLBI analysis, software development, and research aimed at improving the VLBI technique, especially for support of

the Radioastron mission.

2 Component Description

AC SAI performs data processing of all kinds of VLBI

observation sessions. For VLBI data analysis we use

the ARIADNA software package developed at SAI.

Version 4 was finished and tested in 2012. All reductions are performed in agreement with the IERS Conventions (2010).

Sternberg State Astronomical Institute (SAI) of Lomonosov

Moscow State University

SAI Analysis Center

IVS 2013 Annual Report

The package uses files in the NGS format as input

data.

Package ARIADNA (v. 4) is the basis of software

named ORBITA installed on the correlator of the AstroSpace Center of Lebedev Physical Institute. It is

used for correlation of the ground-space interferometer data during the Radioastron mission.

3 Staff

• Vladimir Zharov, Prof.: development of the ARIADNA software, development of the methods of

parameter estimation;

• Leila Kuznetsova, post-graduate student: VLBI

data processing, nutation modeling;

• Nikolay Voronkov, scientific researcher: global solution;

• Svetlana Nosova, engineer: VLBI data processing;

• Natalya Shmeleva, engineer: VLBI data processing.

4 Current Status and Activities

• Software development for VLBI processing

The ARIADNA software is being developed to provide contributions to IVS products. The software is

used for calculating all types of IVS products. Version 4 was developed in 2012. The main features of

this version are performing all reductions in agreement with the IERS Conventions (2010), generation of the SINEX files, and combination of some

of the SINEX files to stabilize solution.

316
SAI 2013 Report 317

This version of the software was corrected in 2013:

now it is possible to use the CIO based transformation matrix. A new series of the EOP was obtained

from observations that were made in 2013.

The method that uses calculation of the equinoxbased transformation matrix for precessionnutation was kept to compare new series with

old ones. The equinox-based matrix Q(t) that

transforms from the true equinox and equator

of date system to the GCRS is composed of the

classical nutation matrix, the precession matrix

including four rotations, and a separate rotation

matrix for the frame biases. A new series of the

nutation angles will be used for the preparation of

our suggestion for improving the nutation theory.

Some corrections of the model of delay for the

ground-space interferometer were made and realized in software ORBITA, which is used for the

correlation and routine analysis of the Radioastron

observations.

• Routine analysis

During 2013 the routine data processing was

performed with the ARIADNA software using the

least-squares method with rigid constraints, and

non-rigid constraints were used for generation of

SINEX files.

AC SAI operationally processed the 24-hour and

Intensive VLBI sessions. The formation of the

databases of the VLBI sessions and processing of

all sessions is fully automated. The EOP series

sai2013a.eops and sai2013a.eopi were calculated.

These series were computed with the VTRF2008

catalog of station positions and velocities. Experimental series sai2013c.eops was calculated with

the CIO based transformation matrix. New EOP

series will be used for the development of new

nutation theory.

IVS 2013 Annual Report
SHAO Analysis Center 2013 Annual Report

Guangli Wang, Jinling Li, Minghui Xu, Li Guo, Li Liu, Fengchun Shu, Zhihan Qian, Liang Li

Abstract This report presents the routine work and the

pertinent research of the SHAO VLBI Analysis Center

(AC) during 2013. The SHAO AC continued routine

VLBI data analysis of 24-hour geodetic/astrometric

observations to make products. The activities of SHAO

AC in 2013 also included reduction of data from the

Chinese VLBI Network (CVN), providing navigation

for Chang’E-3 using the VLBI technique, and basic

research in Astrometry, specifically theoretical discussions on the Celestial Reference Frame and the effect

of aberration.

1 General Information

In 2013, one of the important activities at SHAO

AC was real-time navigation by using VLBI for the

Chang’E 3 satellite that launched on December 02,

2013. This work involved scheduling, observing,

processing, and analyzing VLBI experiments, which

lasted until early 2014. Our routine data analysis

contained two parts: the IVS 24-hour sessions and

the CVN experiments that aim to monitor the crustal

movement of the Chinese mainland. In addition, research topics focused on the CRF and the astrometric

effects that are outlined in Section 3. The members

involved in these activities were Guangli Wang, Jinling

Li, Minghui Xu, Li Guo, Liang Li, Fengchun Shu, and

Zhihan Qian.

SHAO, Chinese Academy of Sciences

SHAO Analysis Center

IVS 2013 Annual Report

2 Activities and Data Analysis at SHAO

SHAO is in charge of the CVN and is an Analysis

Center of the IVS. Routine VLBI activities at SHAO

included:

-The geodetic experiments and observations of

MSP by the CVN

As usual, in 2013, the CVN conducted six 24-

hour geodetic sessions which aimed at monitoring

the CVN network and at determining the accurate

position for the new 65-meter antenna in Shanghai, the

TIANMA65. The experiment of MSP J1939+2134,

with three CVN antennas — SH 25 m, UR 25 m,

and KM 40 m — was on September 30, 2013. The

calibrator of MSP J1939+2134 in our observation

was J1935+2031, which has 1.5 degrees of separation

from the pulsar and has a position precision of ∼ 0.1

mas. The CVN observation mode was fast-switching

between the pulsar and calibrator with a cycle time of

180 s on the pulsar and 80 s on the calibrator, and the

total recording rate reached 1024 Mbps.

-Post processing of the VLBI observations for

the navigation of Chang’E 3 satellite.

We conducted the post processing of the VLBI

observations for the navigation of the Chang’E 3

satellite, and obtained the differential group delay

between the rover and the satellite with accuracy to a

level better than 0.5 ns. The accuracy of the relative

position of the rover and the satellite finally is at

the meter level, based on the research of differential

observations.

318
SHAO AC 2013 Annual Report 319

-Data processing and analysis of the CVN geodetic experiments

The relative work consists of the calculation of

the delay and delay rate of CVN observations at

every band, the resolution of group delay ambiguities,

and the computation of ionosphere calibrations. In

addition, SHAO is responsible for the generation of

the VLBI group delay in NGS format and for the

analysis of all CVN sessions by the software shops,

which has been developed based on the software

OCCAM6.1E(Linux) with modifications mainly in

VLBI data process models.

-Regular data analysis of the IVS 24h sessions

and product submission

We continued to routinely analyze all IVS 24-hour

sessions using the CALC/SOLVE software, and we

regularly submitted our analysis products (EOP,

TRF, and CRF) to the IVS Data Centers. In order to

contribute to the forthcoming ITRF2013 activity, we

updated the geophysical and astronomical models,

including the IAU 2006 nutation/precession, the ocean

loading model, atmospheric pressure loading, the

Vienna Mapping Function, and the antenna thermal

deformation model.

3 Research Topics at SHAO

3.1 Validation of Solar Acceleration

In 2011 and 2012, we obtained the acceleration vector

in the three components in the Galactic coordinate system (7.47±0.46, 0.17±0.57, 3.95±0.47) mm·s

−1

·yr−1

[1]. Traditionally, it was generally believed that the acceleration component in the direction normal to the

Galactic plane was too small to be detected and that the

acceleration vector should nearly point to the Galactic

center, but our results showed that the vertical acceleration is notable. This year, we tried variant methods

to validate this result. For example, we made two solutions with the same parameterizations and the same

strategy except for a defining source, 2136+141. One

solution took into account the effect of the acceleration on all sources, while another one took into account

the effect of the acceleration on all except 2136+141.

These two solutions treated the position of this source

as a local parameter to obtain the time series of its

position. Figure 1 shows the difference of these two

time series, which demonstrates that the accordance

between the predicted model and the time series obtained from VLBI data is quite well. The time series of

the position of a single source clearly show the effect

of the Solar acceleration, which demonstrates that the

software and data are sensitive to the microarcsecond

level.

Fig. 1 The time series of 2136+141, obtained from two solutions.

3.2 The Aberration Effect

There was a groundbreaking step in the history of astronomy in 1728 when the effect of aberration was discovered by James Bradley (1693-1762). Recently, due

to the variations in the aberrational effect of extragalactic sources caused by the Solar acceleration, the latter

has been determined from VLBI observations with the

uncertainty of about 0.5 mm/s/yr level. As a basic concept in astrometry with a nearly 300-year history, the

definition of aberration is still equivocal and discordant

in much of the literature. It has been under a continuing debate whether it depends on the relative motion

between the observer and the observed source or only

on the motion of the observer with respect to the frame

of reference. We think that the aberration is essentially

caused by the transformation between coordinate sysIVS 2013 Annual Report
320 Wang et al.

tems and is consequently quantified by the velocity

of the observer with respect to the selected reference

frame, independent of the motion of the source [2]. Obviously, this nature is totally different from that of the

definition given by the IAU WG NFA in 2006, which is

stated as “The apparent angular displacement of the observed position of a celestial object from its geometric

position, caused by the finite velocity of light in combination with the motions of the observer and of the

observed object” [3, 4]. The IAU’s definition has already led to some confusion and misunderstandings in

the recent studies.

4 Plans for 2014

We will make a contribution to the ITRF2013 campaign and study the potentially systematic variances in

the direction displacements of radio sources with the

aim to improve the accuracy of their positions.

References

1. M. H. Xu, G. L. Wang, and M. Zhao, A New concept of the

International Celestial Reference Frame: the Epoch ICRF.

MNRAS, 2013.

2. G. L. Wang, M. H. Xu, and M. Zhao, On the Definition of

Aberration. (In preparation)

3. N. Capitaine, A. H. Andrei, M. R. Calabretta et al., Proposed Terminology in Fundamental Astronomy Based on

IAU 2000 Resolutions. Highlights of Astronomy, 2007, 14,

474C475

4. 4 IAU 2006 NFA GLOSSARY, 2006, URL

http://syrte.obspm.fr/iauWGnfa/

IVS 2013 Annual Report
Tsukuba VLBI Analysis Center

Shinobu Kurihara 1, Tetsuya Hara 1,2

Abstract This report summarizes the activities of

the Tsukuba VLBI Analysis Center during 2013. The

weekend IVS Intensive (INT2) sessions were regularly

analyzed using c5++ analysis software. Several ultrarapid EOP experiments were implemented in association with Onsala, Hobart, and HartRAO.

1 Introduction

The Tsukuba VLBI Analysis Center located in

Tsukuba, Japan, is operated by the Geospatial Information Authority of Japan (GSI). A major role of us is

to regularly analyze the weekend IVS Intensive (INT2)

sessions using the fully automated VLBI analysis

software c5++ developed by the National Institute of

Information and Communications Technology (NICT)

[1]. It should be noted that the UT1-UTC (= dUT1)

solution becomes available within a few minutes after

the end of the last scan of the session. A 10 Gbps

dedicated link to the SINET4 operated by the National

Institute of Informatics (NII) and several process

management programs make it possible to derive a

solution rapidly. Other than that, the ultra-rapid EOP

experiments behind 14 regular IVS 24-hour sessions

and three dedicated ultra-rapid experiments were

implemented in 2013.

1. Geospatial Information Authority of Japan

2. Advanced Engineering Service Co.,Ltd.

Tsukuba VLBI Analysis Center

IVS 2013 Annual Report

2 Component Description

2.1 Fully Automated VLBI Analysis

Software c5++

c5++, which is an analysis software for space geodesy

including SLR, GNSS, and VLBI, has been undergoing

several modifications and updates by NICT and was installed on a host at the Tsukuba Analysis Center in the

summer of 2012. In April 2013, we officially started to

use c5++ and to provide a dUT1 solution in the regular INT2 session. C5++ supports flexible parameterization (X-pole, Y-pole, dUT1, nutation, station clocks,

and troposphere) and SINEX input/output with covariance matrix. Therefore it is also used in the ultra-rapid

EOP experiments (see Section 4.2).

2.2 Calc/Solve

Calc/Solve has been in use throughout from the early

days of VLBI work in GSI. It is used for the analysis

of JADE, which is the Japanese domestic observation

for geodesy, in its interactive mode and for global analysis in the batch mode, which is for the purpose of our

internal use, not for the IVS products as an Analysis

Center.

2.3 Potential to Use VieVS

VieVS, developed by the Institute of Geodesy and Geophysics (IGG) of the Vienna University of Technol321
322 Kurihara and Hara

Table 1 Analysis Center Hardware Capabilities.

Number of servers 4 for VLBI analysis (c5++, Calc/Solve, and VieVS)

Operating System CentOS version 5.4, 5.5, or Red Hat Enterprise Linux 6.3

CPU Intel Xeon @3.80GHz CPU x 2, Intel Xeon 5160

@3.00GHz dual CPU x 2, Intel Xeon X3360 @2.83GHz quad CPU,

Intel Xeon X5687 @3.60GHz quad CPU x 2

Total storage capacity individual RAIDs: 2.79 Tbytes in total

ogy, has already been installed in the Tsukuba Analysis

Center [2]. But it has not been operational yet. VieVS is

quite interesting VLBI analysis software, having some

unique features that are not seen in other software. We

would like to start to use it soon and to utilize the features for our analysis work.

2.4 Analysis Center Hardware Capabilities

Both c5++ and Calc/Solve are installed on several

general-purpose and commercially-produced Linux

computers (Table 1). MATLAB as a platform for

VieVS is also available on a host. Individual RAIDs are

mounted on each host for storing a lot of VLBI data

files such as Mark III databases.

3 Staff

The technical staff in the Tsukuba Analysis Center are

• Shinobu Kurihara: correlator/analysis chief, management.

• Tetsuya Hara (AES): correlator/analysis operator,

software development.

4 Analysis Operations

4.1 IVS Intensive for UT1-UTC

72 IVS Intensive sessions were analyzed at the

Tsukuba Analysis Center, and dUT1 results were

submitted as gsiint2b.eopi to the IVS Data Center

(Table 2). Only the dUT1 parameter was estimated

with station positions fixed to a-priori. For the Tsukuba

station after the 2011 Tohoku Earthquake, the position

correcting its non-linear post-seismic motion provided

by NASA/GSFC was used.

In 2013, the Tsukuba—Wettzell baseline and several other baselines were analyzed. The observed data

at Wettzell is transferred to the Tsukuba Correlator in

real-time with the VDIF/SUDP protocol. The correlated data is rapidly analyzed by c5++ as soon as all

the correlator outputs come in, and then a dUT1 solution is derived. Figure 1 shows that 90% of the total sessions complete analysis within five minutes after

the end of the last scan. The end time of IVS-INT2 session is 8:30 UT on every Saturday and Sunday. Thus,

the dUT1 solution is available at latest by 8:40. This

is really an advantage of the Tsukuba Analysis Center. The eopi file, a product of Intensive analysis from

the Analysis Center, is submitted immediately after the

analysis and becomes accessible to users as an IVS

product. The whole process of work from data transfer through submission of products is automated. Our

products are utilized for more accurate dUT1 prediction by the U.S. Naval Observatory (USNO) as the

IERS Rapid Service/Prediction Centre, which is responsible for providing earth orientation parameters on

a rapid turnaround basis, primarily for real-time users

and others needing the highest quality EOP information sooner than that available in the final EOP series.

In the case of Kokee baselines, because the observed

data at Kokee was transferred via USNO, it took a few

hours to derive a solution.

Table 2 Intensive sessions analyzed at the Tsukuba Analysis

Center.

Baseline # of sessions Average of dUT1 sigma

Intensive 1 TsWz 7 9.7 μsec

Intensive 2 TsWz 34 8.1 μsec

KkWz 19 14.6 μsec

KkNy 9 17.3 μsec

KkSv 3 19.9 μsec

Total 72 11.6 μsec

IVS 2013 Annual Report
Tsukuba Analysis Center 323

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9 10

Number of sessions [%] 

Latency [min.] 

Fig. 1 Latency–number of sessions as % of 36 Tsukuba-Wettzell sessions. Five sessions with some sort of trouble during the session

are excluded.

-200

-150

-100

-50

 0

 50

 100

 150

 200

2012 / 01 2012 / 07 2013 / 01 2013 / 07 2014 / 01

UT1-UTC w.r.t. IERS EOP 08 C04 (usec)

Year / Month

TsWz : Bias = 9.97 (usec), WRMS = 1.95 (usec)

KkWz : Bias = -3.32 (usec), WRMS = 3.19 (usec)

KkNy : Bias = 10.28 (usec), WRMS = 6.93 (usec)

KkSv : Bias = -79.01 (usec), WRMS = 42.35 (usec)

Fig. 2 The time series of UT1-UTC derived from IVS Intensive w.r.t. IERS EOP 08 C04. Error bars are 1 σ formal uncertainties.

Figure 2 shows the differences between the dUT1

solutions of each Intensive baseline and IERS EOP 08

C04 from January 2012 through January 2014.

4.2 Ultra-Rapid EOP Experiment

This session started in 2007 as a joint project of Japan

(Tsukuba and Kashima) and Fennoscandia (Onsala and

Metsahovi). It aims to derive a consecutive time series  ̈

of EOP as soon as possible. The observed data is sent

in real-time via the international optical fiber backbone

to Tsukuba where the data is correlated and analyzed.

C5++ is used in the whole analysis.

Nowadays four countries — Japan, Sweden, Australia, and South Africa — are involved in association with Onsala, Hobart, and HartRAO. In 2013, three

ultra-rapid EOP experiments with dedicated schedules

were conducted (Table 3). The first session UR1301

with four stations — Hobart, HartRAO, Onsala, and

Tsukuba — in January lasted for 61 hours without any

major failures, and polar motion and dUT1 were determined ultra-rapidly during the ongoing experiment.

The second experiment UR1302 in February was also

IVS 2013 Annual Report
324 Kurihara and Hara

-80700

-80600

-80500

-80400

-80300

-80200

-80100

-80000

20:00 00:00 04:00 08:00 12:00 16:00

UT1-UTC [usec]

Time (2013/12/16-17:00:00 - 2013/12/17-17:00:00)

prediction

UT1-UTC

Fig. 3 The time series of UT1-UTC derived from the Onsala–Tsukuba baseline from IVS-R1616 ultra-rapid processing with the

prediction (Rapid Service/Prediction of Earth Orientation, finals2000A.daily).

successful with three stations — Hobart, HartRAO, and

Tsukuba.

In addition, 14 regular IVS 24-hour sessions that

involved at least two stations out of Hobart, HartRAO,

Onsala, and Tsukuba were also operated with the ultrarapid processing. The sessions are listed in Table 3. Six

of them were originally scheduled with three of the

stations. But a fourth station was added to them via

the tag-along function of SKED, and these six sessions

observed a four-station/six-baseline network. Two experiments in December with one baseline, Onsala—

Tsukuba, were completed without even any minor failures, and a dUT1 time series was produced in near

real-time. Figure 3 shows the time series of dUT1 from

IVS-R1616 ultra-rapid processing.

5 Outlook

We will continue to analyze the data of the IVS-INT2

sessions and submit dUT1 products with a low latency.

CONT14 planned for May 2014 is a good opportunity

to conduct the 15-day continuous ultra-rapid processing. And we might start to use VieVS in part of our

analysis work.

Table 3 The ultra-rapid experiments in 2013. “*” means the station is not included in the original schedule but added by SKED

tag-along.

Exper. Date Time Dur. Stations #obs.

(skd) (cor)

with dedicated schedule

UR1301 Jan 30 18:00 61 HbHtOnTs 1467 1326

UR1302 Feb 05 17:30 48.5 HbHtTs 943 815

UR1303 Dec 05 18:30 24 OnTs 611 606

behind IVS 24-hr schedule

R1569 Jan 22 17:00 24 HbHhOnTs 541 539

R1570 Jan 28 17:00 24 HhOnTs 309 297

RD1301 Jan 29 17:30 24 HhOnTsHb* 394 392

R1573 Feb 18 17:00 24 HbOnTsHt* 565 513

T2088 Feb 19 17:30 24 HhOnTsHb* 275 247

R1579 Apr 02 17:00 24 HhOnTs 293 276

R1580 Apr 08 17:00 24 HtOnTsHb* 432 229

RD1302 Apr 09 17:30 24 HhOnTsHb* 482 -

R1582 Apr 22 17:00 24 HhOnTsHb* 348 332

R1592 Jul 01 17:00 24 HbHhOn 122 114

R1598 Aug 12 17:00 24 HbHhHtOn 323 262

RD1306 Aug 21 18:00 24 HoHhOn 140 110

R1615 Dec 09 17:00 24 OnTs 171 171

R1616 Dec 16 17:00 24 OnTs 196 195

References

1. Hobiger, T., et al.: Fully automated VLBI analysis with c5++

for ultra-rapid determination of UT1, Earth Planets Space,

62, 933-937, 2010.

2. Bohm, J., et al.: The New Vienna VLBI Software VieVS, In  ̈

Proceedings of IAG Scientific Assembly 2009, International

Association of Geodesy Symposia Series, 136, edited by S.

Kenyon, M. C. Pacino, and U. Marti, doi: 10.1007/978-3-

642-20338-1 126, 1007-1011, 2012.

IVS 2013 Annual Report
U.S. Naval Observatory VLBI Analysis Center

Alan Fey, Nicole Geiger, Chris Dieck

Abstract This report summarizes the activities of

the VLBI Analysis Center at the United States Naval

Observatory for calendar year 2013. Over the course

of the year, Analysis Center personnel continued

analysis and timely submission of IVS-R4 databases

for distribution to the IVS. During the 2013 calendar

year, the USNO VLBI Analysis Center continued to

use the VLBI global solution designated usn2012b.

Earth orientation parameters (EOP) based on this

solution and updated by the latest diurnal (IVS-R1

and IVS-R4) experiments, were routinely submitted

to the IVS. Sinex files based upon the bi-weekly

24-hr experiments were also submitted to the IVS.

During the 2013 calendar year, Analysis Center

personnel continued a program to use the Very Long

Baseline Array (VLBA) operated by the NRAO for

the purpose of measuring UT1–UTC. Routine daily

1.5-hour duration Intensive observations continued

using the VLBA antennas at Pie Town, NM and Mauna

Kea, HI. High-speed network connections to these

two antennas are now routinely used for electronic

transfer of VLBI data over the Internet to a USNO

point of presence. A total of 345 VLBA Intensive

experiments were observed, electronically transferred

to, and processed at USNO in 2013.

U.S. Naval Observatory

USNO Analysis Center

IVS 2013 Annual Report

1 Introduction

The USNO VLBI Analysis Center is supported and operated by the United States Naval Observatory (USNO)

in Washington, DC. The primary services provided by

the Analysis Center are the analysis of diurnal experiments, the production of periodic VLBI global solutions for estimation of the Terrestrial Reference Frame

(TRF), the Celestial Reference Frame (CRF), and Earth

Orientation Parameters (EOP). The Analysis Center

continued the submission to the IVS of Intensive (EOPI) and session-based (EOP-S) Earth orientation parameters based on USNO VLBI global solutions. Analysis Center personnel maintain the necessary software

required to continue these services to the IVS including periodic updates of the GSFC CALC/SOLVE software package. In addition to operational VLBI analysis, Analysis Center personnel are actively engaged in

research related to future reference frames, the electronic transfer of VLBI data, and software correlation.

2 Current Analysis Center Activities

2.1 IVS Experiment Analysis and

Database Submission

During the 2013 calendar year, personnel at the USNO

VLBI Analysis Center continued to be responsible for

the timely analysis of the IVS-R4 experiments, with

the resulting databases submitted within 24 hours of

correlation for dissemination by the IVS. Analysis

Center personnel continue to be responsible for the

analysis and database submission for the periodic

325
326 Fey et al.

IVS-CRF experiments. In 2013, USNO scheduled

and analyzed 12 CRF related experiments including

IVS-CRF73 through IVS-CRF79 and IVS-CRDS63

through IVS-CRDS68. The analyzed databases were

submitted to the IVS. Analysis Center personnel also

continued analyzing IVS Intensive experiments for

use in the USN-EOPI time series and continued a new

series of Intensive sessions using the VLBA antennas

at Pie Town, NM and Mauna Kea, HI.

2.2 Global VLBI Solutions, EOP and Sinex

Submission

USNO VLBI Analysis Center personnel continued

to use the periodic global TRF/CRF/EOP solution

usn2012b over the course of the 2013 calendar year.

Analysis Center personnel continued to submit the

USN-EOPS series, which is based upon the current

global solution, and updated with new IVS-R1/R4

experiments. The updated EOPS series is submitted to

the IVS twice weekly within 24 hours of experiment

correlation and is included in the IERS Bulletin A.

Analysis Center personnel also continued routine

submission of Sinex format files based upon the 24-hr

VLBI sessions. In addition to EOPS and Sinex series,

USNO VLBI Analysis Center personnel continued to

produce and submit an EOPI series based upon the

IVS Intensive experiments.

2.3 Software Correlator

Over the course of the 2013 calendar year, Analysis

Center personnel continued the implementation, testing and evaluation of the DiFX software correlator.

Phase I of the software correlator has two management nodes, 33 compute nodes (with each node having a 2.9 GHz dual-core processor with eight cores per

processor for a total of 528 processing cores) and has

been operating since September 2012. Phase II of the

software correlator is expected to be delivered in the

second quarter of 2014 and will double the processing power of the Phase I correlator. Post-correlation

calibration and analysis of software correlated data is

now routinely performed using the standard geodetic

data reduction path including the use of the Haystack

Observatory Post-processing System (HOPS) for data

calibration and the GSFC CALC/SOLVE package for

data analysis.

2.4 VLBA Intensive Experiments

During the 2013 calendar year, Analysis Center personnel continued a program to use the Very Long Baseline Array (VLBA) operated by the NRAO for the

purpose of measuring UT1–UTC. Routine daily 1.5-

hour duration Intensive observations continued using

the VLBA antennas at Pie Town, NM and Mauna Kea,

HI. High-speed network connections to these two antennas are now routinely used for electronic transfer of

VLBI data over the Internet to a USNO point of presence.

A total of 345 VLBA Intensive experiments were

observed, electronically transferred to and processed at

USNO in 2013. Once fully operational, these VLBA

Intensive sessions will be scheduled as IVS-INT4 and

data will be released to the IVS for community-wide

distribution.

3 Staff

The staff of the VLBI Analysis Center is drawn from

individuals in both the Astrometry and Earth Orientation departments at the U.S. Naval Observatory. The

staff and their responsibilities are as follows:

Name Responsibilities

Alan Fey Periodic global CRF/TRF/EOP solutions

and comparisons; CRF densification research; software correlator implementation; VLBI data analysis.

Nicole Geiger software correlator implementation;

VLBI data analysis; EOP, database and

Sinex submission.

Chris Dieck software correlator implementation;

VLBI data analysis; EOP, database and

Sinex submission.

IVS 2013 Annual Report
USNO Analysis Center 327

4 Future Activities

The following activities for 2014 are planned:

• Continue analysis and submission of IVS-R4 experiments for dissemination by the IVS.

• Continue the production of periodic global

TRF/CRF/EOP solutions and the submission

of EOP-S estimates to the IVS updated by the

IVS-R1/R4 experiments.

• Continue submission of Sinex format files based on

the 24-hr experiments, and begin production of a

Sinex series based upon the Intensive experiments.

• Continue the analysis of IVS Intensive experiments

and submission of EOP-I estimates to the IVS.

• Continue the scheduling, analysis and database

submission for IVS-CRF, IVS-CRMS and IVSCRDS experiments.

• Continue testing and evaluation of the USNO

implementation of the DiFX software correlator.

Streamline pre- and post-correlation processing.

• Continue routine electronic transfer, correlation,

post-processing and analysis of VLBI Intensive

data from the MK and PT VLBA stations.

• Continue graphical user interface (GUI) development for the USNO implementation of the DiFX

software correlator.

IVS 2013 Annual Report
USNO Analysis Center for Source Structure Report

Alan Fey, Ralph Gaume

Abstract This report summarizes the activities of the

United States Naval Observatory Analysis Center for

Source Structure for calendar year 2013 and the activities planned for the year 2014.

1 Analysis Center Operation

The Analysis Center for Source Structure is supported

and operated by the United States Naval Observatory

(USNO). The charter of the Analysis Center is to provide products directly related to the IVS determination of the “definition and maintenance of the celestial reference frame.” These include, primarily, radio

frequency images of International Celestial Reference

Frame (ICRF) sources, intrinsic structure models derived from the radio images, and an assessment of the

astrometric quality of the ICRF sources based on their

intrinsic structure.

The Web server for the Analysis Center is hosted

by the USNO and can be accessed by pointing your

browser to

http://rorf.usno.navy.mil/ivs saac/

The primary service of the Analysis Center is the

Radio Reference Frame Image Database (RRFID), a

Web accessible database of radio frequency images of

ICRF sources. The RRFID contains 7,279 Very Long

Baseline Array (VLBA) images of 782 sources at radio frequencies of 2.3 GHz and 8.4 GHz. Additionally,

the RRFID contains 1,867 images of 285 sources at

U.S. Naval Observatory

USNO Analysis Center for Source Structure

IVS 2013 Annual Report

frequencies of 24 GHz and 43 GHz. The RRFID can

be accessed from the Analysis Center Web page or directly at

http://rorf.usno.navy.mil/rrfid.shtml

The RRFID also contains 74 images of 69 Southern

Hemisphere ICRF sources using the Australian Long

Baseline Array (LBA) at a radio frequency of 8.4 GHz.

Images of ICRF sources can also be obtained from

the Bordeaux VLBI Image Database (BVID) at

http://www.obs.u-bordeaux1.fr/m2a/BVID

2 Current Activities

Maintaining the Radio Reference Frame Image

Database as a Web accessible database of radio

frequency images of ICRF sources.

3 Staff

The staff of the Analysis Center is drawn from individuals who work at the USNO. The staff are: Alan L. Fey

and Ralph A. Gaume.

328
Center for Source Structure 329

4 Future Activities

The Analysis Center currently has a program of active research investigating the effects of intrinsic source

structure on astrometric position determination. Results of this program are published in the scientific literature.

The following activities for 2014 are planned:

• Continue with the imaging and analysis of VLBA

2.3/8.4/24/43 GHz experiments.

• Maintain the Radio Reference Frame Image

Database (RRFID) as a Web accessible database of

radio frequency images of ICRF sources.

5 Relevant Publications

Publications of relevance to Analysis Center activities:

• “Relativistic Jets in the Radio Reference Frame Image Database. II. Blazar Jet Accelerations from the

First 10 Years of Data (1994-2003),” Piner, B. G.,

Pushkarev, A. B., Kovalev, Y. Y., Marvin, C. J.,

Arenson, J. G., Charlot, P., Fey, A. L., Collioud, A.,

& Voitsik, P. A. 2012, ApJ, 758, 84

• “Characterization of long baseline calibrators at 2.3

GHz,” Hungwe, F., Ojha, R., Booth, R. S., Bietenholz, M. F., Collioud, A., Charlot, P., Boboltz, D.,

& Fey, A. L. 2011, MNRAS, 418, 2113.

• “The Position/Structure Stability of Four ICRF2

Sources,” Ed Fomalont, Kenneth Johnston, Alan

Fey, Dave Boboltz, Tamoaki Oyama, and Mareki

Honma, 2011, AJ, 141, 91.

IVS 2013 Annual Report
Vienna Special Analysis Center Annual Report 2013

Johannes Bohm  ̈

1

, Sigrid Bohm  ̈

1

, Andreas Hellerschmied 1, Armin Hofmeister 1, Hana Krasn  ́ a ́

1

, Matthias

Madzak 1, David Mayer 1, Lucia Plank 1, Benedikt Soja 2,1, Jing Sun 3,1, Claudia Tierno Ros 1

Abstract The main activities in 2013 of the VLBI

group at the Department of Geodesy and Geoinformation of the Vienna University of Technology were related to scheduling and simulations of VLBI observations, global solutions with the determination of celestial and terrestrial reference frames, and satellite observations with VLBI radio telescopes. A highlight was

certainly the fourth VieVS User Workshop in September 2013 in Vienna with the release of VieVS Version

2.1.

1 General Information

The Department of Geodesy and Geoinformation

(GEO) in the Faculty of Mathematics and Geoinformation of the Vienna University of Technology is

divided into seven research groups. One of those, the

research group Higher Geodesy (Hohere Geod  ̈ asie  ̈ )

with about 15 members, is focusing on satellite

geodesy, system Earth, and geodetic VLBI.

2 Staff

Personnel at GEO associated with the IVS Special

Analysis Center in Vienna (VIE) and their main research fields and activities are summarized in Table 1.

1. Vienna University of Technology

2. GeoForschungsZentrum Potsdam

3. Shanghai Astronomical Observatory

VIE Analysis Center

IVS 2013 Annual Report

The staff members are partly paid by the university and

partly by project money.

Fig. 1 Members of the Vienna VLBI group in front of the VLBI

radio telescope in Metsahovi during the EVGA Working Meet-  ̈

ing 2013 (from left): Caroline Schonberger (Master student),  ̈

Matthias Madzak, Johannes Bohm, Hana Kr  ̈ asn  ́ a, Lucia Plank,  ́

Benedikt Soja, Kamil Teke (Hacettepe University).

3 Activities during the Past Year

3.1 Global Solutions with VieVS

Our latest realizations of global reference frames

are the VieTRF13b terrestrial reference frame,

the VieCRF13b celestial reference frame, and

the corresponding Earth orientation parameters

(EOP) VieEOP13b, all of them being provided at

http://vievs.geo.tuwien.ac.at/results/ and made available as an input option in VieVS. In addition to the

“operational” generation of reference frames and

EOP, the global solution in VieVS was extended by

330
VIE Analysis Center Report 331

Table 1 Staff members ordered alphabetically.

Johannes Bohm ̈ VGOS, atmospheric effects

Sigrid Bohm ̈ VieVS Chair (until 06/2013), Earth orientation

Andreas Hellerschmied (since 11/2013) Satellite observations with radio telescopes

Armin Hofmeister (since 05/2013) Ray-traced delays in VLBI analysis

Hana Krasn  ́ a ́ VieVS Chair (since 06/2013), global solution, celestial and terrestrial reference frames

Matthias Madzak GUIs and special files in VieVS, Earth rotation

David Mayer (since 11/2013) Scheduling and simulation

Lucia Plank Satellite tracking with VLBI

Benedikt Soja (until 04/2013) Sun corona studies with VLBI

Jing Sun (until 01/2013) Development of scheduling options

Claudia Tierno Ros (until 04/2013) European VLBI sessions, simulations

the ability to estimate amplitudes of seasonal station

motions at annual and semi-annual periods. We not

only compared those variations against hydrological

models, but we used that tool to investigate the

propagation of neglected seasonal station movements

to radio source positions (Krasn  ́ a et al. 2014, [4]) and  ́

we assessed the impact on EOP by the analysis of real

and artificial VLBI observations (Krasn  ́ a and B  ́ ohm ̈

2013, [2]). Several other parameters, such as antenna

axis offsets or atmosphere pressure loading regression

coefficients were also added to the normal equation

system in VieVS.

Furthermore, the global solution in VieVS was used

to analyze the European VLBI sessions. Krasn  ́ a et al.  ́

(2013, [3]) published the velocities of geodetic VLBI

sites as derived from all European VLBI sessions, including a comparison with two global tectonic plate

models, NUVEL-1A and MORVEL, with an earlier

study of European crustal motion from VLBI data presented by Haas et al. (2003, [1]), and with velocities derived from Global Navigation Satellite Systems

(GNSS) observations.

3.2 Ray-traced Delays in the Atmosphere

for Geodetic VLBI

Within the project RADIATE VLBI, funded by the

Austrian Science Fund (FWF), we developed new raytracing software, which is capable of determining slant

path delays for the complete history of VLBI observations. With the use of real meteorological weather data

delivered by numerical weather models, e.g. from the

European Centre for Medium-range Weather Forecasts

(ECMWF), it is possible to determine the actual ray

path and calculate the slant path delay for each observation. In 2013, we successfully set up the routines for

global grids of meteorological data (0.125o) and validated the delays against those from an international

comparison campaign of ray-tracing software (Nafisi

et al., 2012, [5]).

3.3 VLBI Observations to Satellites

At GEO Vienna, research on VLBI observations to

satellites is ongoing. Within the research project D −

V LBI, which is part of the DFG Research Unit SpaceTime Reference Systems for Monitoring Global Change

and for Precise Navigation in Space, a number of simulation studies using VLBI observations to Earth satellites were performed. The goal of these investigations

was to determine station position repeatabilities from

either weekly or session-wise VLBI satellite observations. After certain amendments of VieVS, such observations can now also be integrated into routine VLBI

sessions, and a combined analysis, e.g. estimating common clocks and the troposphere, is possible. As documented in several publications on this topic, we identified observation strategies to determine station position

repeatabilities at the sub-centimeter level, respectively

frame ties in terms of Helmert parameters between the

GNSS frame and the VLBI frame of better than 1 millimeter (Plank, 2013, [6]; Plank et al., 2013, [7]).

Although some satellite observation experiments

have been conducted in the recent years, it has not become a routine operation. To overcome that limitation,

Andreas Hellerschmied in his Master thesis has expanded the current Vienna VLBI Software by adding

a module capable of generating satellite observation

IVS 2013 Annual Report
332 Bohm et al.  ̈

schedules, where the observation plan is set up in an

interactive process. The schedule files (VEX format)

can then be used to perform real experiments. During

this project a close cooperation with the Geodetic Observatory Wettzell (http://www.bkg.bund.de/Wettzell)

evolved. This collaboration made it possible to perform

tests on site and to prove the viability of the developed

software utilizing the instruments at this station.

3.4 Assessing the Sun Corona with VLBI

By using the observational data of twelve dedicated

VLBI experiments in 2011 and 2012, the electron density of the solar corona was determined. It was the first

time that VLBI data was used for this purpose. The results agree well with those obtained by different techniques such as spacecraft tracking (Soja et al., 2013,

[8]). The effect of the coronal plasma had to be separated from other dispersive effects caused by the ionosphere and hardware delays. As a byproduct of our investigations, a procedure to estimate the ionospheric

total electron content of each radio telescope was implemented into VieVS.

Fig. 2 Constellation of Sun corona and close radio sources on 10

July 2012 at 17:30 UT.

3.5 Scheduling and Simulations

Scheduling and simulations with VieVS have played

a very important role for the Vienna VLBI group in

2013. This is certainly based on the close cooperation

with Jing Sun who returned to Shanghai Astronomical

Observatory in February 2013. She has made further

amendments to the scheduling tool of VieVS, e.g. by

providing the tag-along mode capability and other refinements. The scheduling tool in VieVS (Vie SCHED,

Sun et al., 2014, [9]) is now used operationally to

schedule the AUSTRAL VLBI sessions.

Additionally, Vie SCHED has been used to

schedule the continuous VLBI campaign in November/December 2013 with stations in Australia, New

Zealand, and South Africa. This campaign has been

carried out to demonstrate the capabilities of the

southern stations and to investigate the influence of

sources with high structure index on geodetic results.

Figure 3 shows simulation results of source coordinate

estimates in right ascension for “good sources” (structure index 1) and “bad sources” (structure index 4).

Furthermore, there have been studies with the schedulFig. 3 Simulation results of estimates of source positions in right

ascension as derived from simulations for the 15 day continuous

VLBI campaign with stations in Australia, New Zealand, and

South Africa.

ing and simulation tools in VieVS to demonstrate the

importance of specific VLBI sites. For example, we

evaluated the importance of the Hartebeesthoek Radio

Astronomy Observatory (HartRAO) for the current

and future VLBI network. The results suggest that

HartRAO is of high importance for the estimation of

IVS 2013 Annual Report
VIE Analysis Center Report 333

EOP. In particular polar motion and nutation estimates

benefit from HartRAO’s remote location. Based on

scheduling and simulation analysis of the VLBI2010

network, an upgrade from the current antenna to a fast

slewing VLBI2010 antenna was recommended.

4 Future Plans

In 2014, we will continue the development of VieVS,

with special focus on satellite tracking, scheduling,

and the estimation of terrestrial and celestial reference frames. In particular, we will contribute to the

ITRF2013, and we will organize the 5th VieVS User

Workshop in September 2014.

Acknowledgements

We are very grateful to the Austrian Science Fund

(FWF) for supporting our work through projects

P23143 (Integrated VLBI), P25320 (RADIATE VLBI)

and P24813 (SPOT). We also acknowledge the German Research foundation (DFG) for funding project

D-VLBI (SCHU 1103/4-1).

References

1. R. Haas, A. Nothnagel, J. Campbell, E. Gueguen. Recent

crustal movements observed with the European VLBI network: geodetic analysis and results. J Geodyn, 35, pp. 391—

414, 2003.

2. H. Krasn  ́ a, J. B  ́ ohm. Impact of seasonal station motion on  ̈

global reference frames and Earth rotation. AGU Fall Meeting, Poster G13B-0936, San Francisco, USA, 2013.

3. H. Krasn  ́ a, C. Tierno Ros, P. Pavetich, J. B  ́ ohm, T. Nils-  ̈

son, H. Schuh. Investigation of crustal motion in Europe by

analysing the European VLBI sessions. Acta Geodaetica et

Geophysica, 48/4, pp. 389–404, 2013.

4. H. Krasn  ́ a, Z. Malkin, J. B  ́ ohm. Impact of seasonal station  ̈

displacement models on radio source positions. Proceedings of the Journees 2013, Paris, September 2013, submitted  ́

2014.

5. V. Nafisi, L. Urquhart, M. Santos, F. Nievinski, J. Bohm,  ̈

D. Wijaya, H. Schuh, A. Ardalan, T. Hobiger, R. Ichikawa,

F. Zus, J. Wickert, P. Gegout. Comparison of Ray-Tracing

Packages for Troposphere Delays. IEEE Transactions on

Geoscience and Remote Sensing, Vol. 50, No. 2, pp. 469–

481, 2012.

6. L. Plank. VLBI satellite tracking for the realization of frame

ties. Dissertation at the Vienna University of Technology,

http://www.ub.tuwien.ac.at/diss/AC11121594.pdf ,2013.

7. L. Plank, J. Bohm, H. Kr  ̈ asn  ́ a, H. Schuh. VLBI satellite  ́

tracking for precise coordinate determination - a simulation study. Proceedings of the 21st Meeting of the European VLBI Group for Geodesy and Astrometry, N. Zubko,

M. Poutanen (ed.), ISBN: 978-951-711-296-3, pp. 105–109,

2013.

8. B. Soja, J. Sun, R. Heinkelmann, H. Schuh, J. Bohm. Sun  ̈

Corona Electron Densities Derived from VLBI Sessions in

2011/2012. Proceedings of the 21st Meeting of the European VLBI Group for Geodesy and Astrometry, N. Zubko,

M. Poutanen (ed.), ISBN: 978-951-711-296-3, pp. 159–163.

9. J. Sun, J. Bohm, T. Nilsson, H. Kr  ̈ asn  ́ a, S. B  ́ ohm, H. Schuh.  ́

New VLBI2010 scheduling strategies and implications on

the terrestrial reference frames. Journal of Geodesy, in press

2014.

IVS 2013 Annual Report

Technology Development Centers

Canadian VLBI Technology Development Center Report

Bill Petrachenko

Abstract The Canadian VLBI Technology Development Center (TDC) is involved in activities related to

the realization of the VLBI Global Observing System

(VGOS).

1 General Information

The Canadian TDC is a collaborative effort of the

National partners interested in the advancement of

VLBI technology, namely the Canadian Geodetic

Survey (CGS) of Natural Resources Canada (NRCan)

and the Dominion Radio Astrophysical Observatory

(DRAO) of the National Research Council of Canada

(NRC).

2 Activities during the Past Year

The Canadian TDC is primarily focused on encouraging the realization of VGOS. This is done by Bill

Petrachenko of NRCan who is the IVS Technology

Development Coordinator, the chairman of the VGOS

Technical Committee (VTC), and a member of the

VGOS Project Executive Group (VPEG). In collaboration with others, this year’s activities focused on the

following areas:

• Development of the VGOS Observing Plan.

• Compilation of a comparison of VGOS recorders.

Canadian Geodetic Survey, Natural Resources Canada

Canadian VLBI Technology Development Center

IVS 2013 Annual Report

• Compilation of a memo on mixed mode oberving

issues.

• Analysis of RFI survey responses.

• Development of FPGA code for VGOS digital back

ends.

In addition, NRC is involved in a number of Square

Kilometer Array (SKA) related activities that have potential applications to the IVS.

• Digital signal processing including development of

correlators, beam formers, and systems for pulsar

processing.

• Fabrication of a light, stiff, and cost effective 15-m

off-axis Gregorian top-fed composite antenna.

• Development of focal plane arrays.

3 Future Plans

The Canadian TDC plans to continue to actively encourage the realization of VGOS.

337
GSFC Technology Development Center Report

Ed Himwich, John Gipson

Abstract This report summarizes the activities of

the GSFC Technology Development Center (TDC) for

2013 and describes plans for 2014. The GSFC TDC

develops station software including the Field System

(FS), scheduling software (SKED), hardware including tools for station timing and meteorology, scheduling algorithms, and operational procedures. It provides

a pool of individuals to assist with station implementation, check-out, upgrades, and training.

1 Technology Center Activities

The GSFC IVS Technology Development Center

(TDC) develops hardware, software, algorithms, and

operational procedures. It provides manpower for

station visits for training and upgrades. Other technology development areas at GSFC are covered by other

IVS components such as the GSFC Analysis Center.

The current staff of the GSFC TDC consists of John

Gipson, Ed Himwich, and Rich Strand, all employed

by NVI, Inc. The remainder of this report covers the

status of the main areas supported by the TDC.

2 Field System

The GSFC TDC is responsible for development, maintenance, and documentation of the Field System (FS)

software package. The FS provides equipment conNASA Goddard Space Flight Center

GSFC Technology Development Center

IVS 2013 Annual Report

trol at VLBI stations. It interprets the .snp schedule

and .prc procedure files (both as prepared by DRUDG

from the .skd schedule). The FS controls the antenna,

data acquisition hardware, and related ancillary equipment needed for making VLBI measurements. All major VLBI data acquisition backends are supported. The

FS is customizable to allow it to control station specific equipment. It is used at almost all the IVS Network Stations (more than 35) and also at many stations

that do VLBI only for astronomical observations. The

only major VLBI facilities not using it are the VLBA

and VERA.

There was one minor release of the FS (9.11.0) during this year. Full details can be found in the FS release

notes, but some of the major changes are listed here:

• Support for the DBBC DDC personality was added,

both for continuous and on-off noise diodes.

• A work around for the “Day 49” kernel issue was

included.

• A new version of the gnplt program, written in

Python, was included.

• A new command, satellite, was added to allow simple pointing at satellites.

• A new command, holog, was added to facilitate

collecting data from holographic antenna measurements.

• The pointing data analysis programs were modified

to plot first antenna coordinate offsets in “cross”

coordinate units, e.g., to use “Cross-El” instead of

Azimuth and to use “cross” coordinate reweighting

constants when fitting the first coordinate offsets.

• The metserver/metclient programs were improved

to better support multiple clients.

• The handling of Mark 5 communications was improved to prevent partial responses from terminat338
GSFC Technology Development Center Report 339

ing input prematurely. There were general improvements to error messages for Mark 5 communications.

In addition several development projects were underway. These include:

• Patriot 12 m Interface. Development of the interface for Patriot Antenna Control Unit (ACU) continued. Several improvements were made including

the handling and the reporting of status word represented errors and improvements in cable-wrap handling to make it independent of the limits for any

particular antenna.

• Mark 5C/RDBE. Preliminary support for Mark 5C

recorders and RDBE DASs was developed to facilitate VGOS test activities. This support will be fed

into the distributed FS next year.

• Miscellaneous. Many small improvements and bug

fixes were made for the new releases expected in

2014. These included a new “time-out” feature for

the onsource command to facilitate local antenna

measurements, making all DBBC IF power measurement displays all consistent support for the

DBBC astro2 mode, and preventing the changing

of schedules while recording.

• VEX2. Considerable effort has gone into defining

the second version of VEX, which will provide

schedule file format support for new “samplingbefore-channelization” systems such as the RDBE.

2.1 Plans for 2014

Several other improvements are expected in future releases, including:

• Support for RDBE racks.

• Support for DBBC PFB personality.

• Support for Mark 5C and Mark 6 recorders.

• Use of idl2rpc for remote operation.

• A complete update to the documentation and conversion to a more modern format that will be easier

to use and maintain.

• Conversion of the FORTRAN source to use the

gfortran compiler, which will enable use of the

source level debugger, gdb, for development and

field debugging.

• Chekr support for Mark 5A and Mark 5B systems.

• FS Linux 9 (based on Debian wheezy, skipping

squeeze) distribution.

• Support for periodic firing of the noise diode during

observations.

• Support for NMEA standard wind sensors.

• Completion of the VEX2 standard and implementation of it.

3 SKED and DRUDG

The GSFC TDC is responsible for the development,

maintenance, and documentation of SKED and

DRUDG. These two programs are very closely related,

and they operate as a pair for the preparation of the

detailed observing schedule for a VLBI session and its

proper execution in the field. In the normal data flow

for geodetic schedules, first SKED is run at the Operation Centers to generate the .skd file that contains

the full network observing schedule. Then stations

use the .skd file as input to DRUDG for making the

control files and procedures for their station. Catalogs

are used to define the equipment, stations, sources, and

observing modes which are selected when writing a

schedule with SKED.

Changes to SKED and DRUDG are driven by

changes in equipment and by feedback from the users.

The following summarizes some of the important

changes to these programs in 2012.

3.1 SKED Changes

• Better calculation of SNR. The calculation now includes the effects of 1- and 2-bit sampling and the

correlator efficiency factor.

• Addition of the descriptive parameters

“SCHEDULING SOFTWARE”, “SOFTWARE

VERSION”, and “SCHEDULE CREATE DATE”.

This was done because vie-sched is now being used

to write some schedules, and we wanted to be able

to tell which software wrote a schedule.

• Addition of the $BROADBAND section to the

schedule file, which provides limited support for

broadband. This section lists the stations that are

observing in broadband and gives the bandwidth of

the observing.

IVS 2013 Annual Report
340 Himwich and Gipson

• Correction of a problem with adding a station to a

schedule that already has observations. This problem occured because each station has a preferred

one-character station code. It is possible to have

two stations with the same preferred code in the

same schedule. In this case, one of the stations will

use another code. Previously, if you added a station

to a schedule and the one-letter code of the station

was already in use, sked would sometimes change

the code for a station in the schedule.

3.2 DRUDG Changes

Many changes were made to support new equipment in

the field, particularly DBBCs. A fuller description can

be found in the FS release notes.

3.3 Plans for 2014

Plans for 2014 include the following:

• In 2012, we began work on making VEX the native

format for SKED. We plan to finish this project in

2014.

• We also plan to expand support for RDBEs and DBBCs. This will involve changes to SKED, DRUDG,

and the catalogs.

• If time permits, we will convert SKED to compile

using a freely available compiler such as gfortran.

IVS 2013 Annual Report
Haystack Observatory Technology Development Center

Christopher Beaudoin, Arthur Niell, Roger Cappallo

Abstract Technology development at MIT Haystack

Observatory focused on three areas in 2013:

• Mark 6

• RDBE 3.0

• KPGO 20-m VGOS Receiver Upgrade

1 Mark 6 High Speed Data Recorder

In 2013, the development and the implementation of

the Mark 6 recording system continued. The software

can now record up to four 2 Gb/s Mark 5B streams,

which are converted on the fly to vdif datastreams differentiated by thread ID. A single 8 disk module in

good health is able to record that 8 Gb/s datarate, or

slightly less. Given that the Mark 6 has a ∼60 GB ram

buffer, the fifo allows scans of several minute duration to be captured in this mode, so long as there is

some time between scans for draining the fifo. Using

the nominal 2-module/16-disk configuration, the full

datastream can be recorded continuously. Similarly, a

16 Gb/s input data rate can be captured for short periods in two modules (= 16 disks), although for continuous recording four modules should be used.

Manufacture of the Mark 6 was transferred to Conduant Corp., and they began filling orders mid-year.

The software is open source, and it is available on

the Haystack website. In addition to the Mark 6 control software, there are various utilities there to allow

for data quality assessment, as well as interim converMIT Haystack Observatory

Haystack Technology Development Center

IVS 2013 Annual Report

sion software for use at correlators. A python program

called RM6 CC allows for control of the hardware via

an XML schedule. Multiple test observation sessions

were held, employing Mark 6s at the Westford and

GGAO antenna sites.

2 RDBE Version 3.0

Development of a new RDBE firmware version 3.0 was

initiated in 2013. The RDBE v3.0 is an operationsoriented personality that represents an enhancement to

the RDBE v1.4 personality. The version 3.0 personality incorporates a number of operations and diagnostic

capabilities that include the following:

• Integrated 1PPS Delay Measurement

• Pulse Calibration Extraction

• 1PPS-triggered raw ADC capture

• Arbitrary test vector injection

In addition to these features, the v3.0 firmware

represents a complete re-engineering of the v1.4 PFB

firmware code. This new development simplified the

firmware signal processing and has been verified

against the theoretical PFB algorithm implemented

in a MATLAB model. The verification process ensures that the RDBE v3.0 signal processing that is

implemented on the Xilinx FPGA IC is performing

the correct operations, and it is anticipated that a test

vector procedure will be incorporated to verify field

installations of the RDBE running this personality.

This verification process is conducted by introducing

a known digital test vector at the frontend (input)

port of the FPGA, recording the resultant output

2-bit samples generated by the FPGA operations, and

341
342 Beaudoin et al.

directly comparing (differencing) the RDBE output

samples to the theoretical sample values computed by

the MATLAB model.

As part of the v3.0 firmware development, the

RDBE server software, which interprets commands

from an external RDBE user, was rewritten to incorporate the additional firmware features that are available

in the v3.0 firmware. As part of the re-write, the

complexity was reduced from approximately 50,000

lines of code to approximately 4,000 lines.

The server software also captures VLBI-critical diagnostic data on each 1PPS pulse, packages the data

into a multicast network packet, and transmits the data

over the 1 GigE network interface for reception by any

client listening on the designated network port. This

diagnostic data includes the current UT time as maintained by the RDBE firmware as well as the delay offsets of this clock relative to the RDBE operating system clock (i.e., server clock), the GPS 1PPS signal, and

the MASER 1PPS signal. Also contained in this multicast packet are the samples of the pulse calibration signal as reconstructed by the pulse calibration extraction

feature and the first 4,000 samples of the 8-bit frontend

ADC samples as triggered by the RDBE 1PPS.

The server also provides an information-rich numerical and graphical output data display that is intended to provide feedback to the RDBE user. This

graphical display updates on each 1PPS pulse and plots

the ADC raw capture samples with the associated histogram and spectrum. This display also plots the reconstructed pulse calibration signal and the noise diode

on and off accumulator counts for each PFB frequency

channel. Figure 1 displays an example of the RDBE

server’s graphical output display.

3 KPGO 20-m VGOS Receiver Upgrade

In 2013, Haystack Observatory developed and fabricated a VGOS receiver frontend upgrade for the

KPGO 20-m radio telescope. Diagrams of the new

receiver frontend are shown in Figure 2. The receiver

enclosure, which is identical in design to the existing

S/X KPGO 20-m receiver enclosure, was provided

by NASA/Excelis and was recovered from a decommissioned/damaged NASA radio telescope. Haystack

refurbished the receiver enclosure and developed a

full 3D mechanical design in the CAD software suite

SolidWorks. This mechnical model also serves as

electronic documentation for the KPGO site personnel

and can be viewed by downloading a free SolidWorks

viewer available at the software vendor’s website.

Similar to previous Haystack broadband receiver

frontend designs, the KPGO frontend incorporates a

customized QRFH feed. This feed was optimized for

the 0.43 focal-length-to-diameter ratio characteristic

of the KPGO 20-m optics. Receive pattern measurements of the cryogenic frontend demonstrate that the

expected broadband aperture efficiency of the KPGO

20-m VGOS system should be approximately 50%

over the 2 to 14 GHz frequency range as shown in Figure 3. The measured noise temperature of the new 20-

m VGOS receiver frontend is shown in Figure 4. Based

on these noise temperature and aperture efficiency estimates, the SEFD of the KPGO 20-m telescope following the VGOS upgrade is expected to be approximately

900 Jy which is equivalent to that of the X-band section

in the existing system. The VGOS receiver frontend

upgrade for the KPGO 20-m antenna was delivered to

Kokee Park in September 2013.

Presently, a failure in the KPGO 20-m frontend receiver “box” rail system is inhibiting removal of the

S/X band receiver frontend section from the antenna.

Installation of the VGOS frontend is awaiting mechanical refurbishment of this rail mechanism.

IVS 2013 Annual Report
Haystack Technology Development 343

Fig. 1 Graphical output display generated by the RDBE v3.0.

Fig. 2 KPGO 20-m VGOS receiver frontend upgrade.

IVS 2013 Annual Report
344 Beaudoin et al.

Fig. 3 Expected aperture efficiency of the KPGO 20-m following the VGOS receiver frontend upgrade.

Fig. 4 Noise temperature of the KPGO 20-m VGOS receiver frontend upgrade.

IVS 2013 Annual Report
NICT Technology Development Center 2013 Annual Report

Kazuhiro Takefuji, Hideki Ujihara

Abstract The National Institute of Information and

Communications Technology (NICT) is developing

and testing VLBI technologies and conducts observations with this new equipment. This report gives

an overview of the Technology Development Center

(TDC) at NICT and summarizes recent activities.

1 NICT as IVS-TDC and Staff Members

The National Institute of Information and Communications Technology (NICT) publishes the newsletter

“IVS NICT-TDC News (formerly IVS CRL-TDC

News)” at least once a year in order to inform

about the development of VLBI related technology as an IVS Technology Development Center.

The newsletter is available at a following URL

http://www2.nict.go.jp/aeri/sts/stmg/ivstdc/newsindex.html. Table 1 lists the staff members at NICT

who are contributing to the Technology Development

Center.

2 General Information

We have been developing a new VLBI system called

Gala-V, which has the VGOS (VLBI2010 Global Observing System) requirements. Distinguishing features

of Gala-V are a direct sampler called Galas and a

Kashima Space Technology Center, National Institute of Information and Communications Technology

NICT Technology Development Center

IVS 2013 Annual Report

Table 1 Staff Members of NICT TDC as of January 2013 (alphabetical).

HASEGAWA, Shingo HOBIGER, Thomas

ICHIKAWA, Ryuichi KAWAI, Eiji

KONDO, Tetsuro KOYAMA, Yasuhiro

MIYAUCHI, Yuka SEKIDO, Mamoru

TAKEFUJI, Kazuhiro TSUTSUMI, Masanori

UJIHARA, Hideki

broadband feed horn called Iguana. Here we will report the current activities. First, we evaluated a jitter

and frequency response of Galas. Secondly, a prototype

of Iguana feed was deployed to the Kashima 34-meter

antenna at the end of December 2013. We could detect

simultaneously methanol maser lines of 6.7 GHz and

12.2 GHz from the star forming region W3OH.

3 Evaluation of Direct Sampler Galas

The broadband signal from 1 GHz to 18 GHz transfers

without frequency conversion via a high sensitivity

optical transmitter and receiver from the antenna

to the sampler Galas. For this reason, Gala-V has

a quite simple system. Actually, our system has no

analog frequency conversion, but we realized the

down-conversion with high order sampling and digital

baseband conversion by digital signal technique inside

Galas. Figure 1 shows the design of Galas. It has

four analog inputs and four 10 GbE outputs. Galas

will sample an input signal at 16 GHz speed and

3-bit quantization and will perform digital frequency

conversion. At first, we evaluated jitter performance

345
346 Takefuji and Ujihara

and a frequency response. We input the sinusoidal

signal from a signal synthesizer to Galas at each

frequency, then calculated the phase noise as a jitter

from the digitized signal. The jitter is shown in Figure

2, where we obtain a result of 0.191 picoseconds.

We expect good sampler performance even at the

frequency of 20 GHz based on the obtained jitter

values. Figure 3 shows the frequency response of

Galas from comparing the amplitude from quantized

bit distribution between reference signal and target

signal.

In 2013, we conducted VLBI experiments between

the direct sampler Galas and the existing wideband

sampler ADS3000+ of 1 GHz bandwidth. And we had

successfully obtained a consistent geodetical result. We

have more plans for broadband VLBI after Iguana feed

installation.

Display LED indicators

Power switch

Four 10 GbE interfaces

Four signal inputs

Fig. 1 The design of the direct sampler Galas.

4 Developing the Broad Band Feed Iguana

The prototype Iguana feeds were multimode horns,

which were designed for 6.4-15 GHz. Their beam patterns were measured at Microwave Energy Transmission Laboratory (METLAB) in Kyoto University. The

first prototype of 133 mm aperture diameter was set on

 0.2

 0.4

 0.6

 0.8

 1

 1.2

 1.4

 0 2 4 6 8 10 12 14 16

Phase noise [deg]

Frequency [GHz]

Fig. 2 The jitter performance of the direct sampler Galas.

-8

-7

-6

-5

-4

-3

-2

-1

 0

 0 2 4 6 8 10 12 14 16 18 20

Attenuation [dB]

Frequency [GHz]

Fig. 3 The frequency response of the direct sampler Galas.

the Kashima 34 meter for testing our wideband frontend system. The aperture size of the second feed is

120 mm.

They can be replaced to select the most efficient

frequency for various observations. Also, waveguide

high-pass filters are ready for fcut=6.4 GHz, 8.0 GHz,

and 9.6 GHz cut-off frequencies to suppress RFI, following WRD580 waveguide and SMA adapter output.

Our configuration is for one linear polarization

now.

5 First Light of Gala-V, Deployed to the

Kashima 34-Meter Antenna

We have deployed the prototype feed to the Kashima

34-meter antenna. The feed after deployment is shown

IVS 2013 Annual Report
NICT TDC 2013 Report 347

in Figure 4. The Kashima 34-meter antenna has four

pedestals for the feed and receiver. We can choose one

pedestal from four pedestals moving exclusively. Figure 5 shows two methanol lines at 6.7 GHz and 12.2

GHz from the star forming region W3OH detected by

the Gala-V system. It was a memorable first light. The

system temperature of the prototype system is shown in

Figure 6. We are currently using ambient temperature

LNA; thus the system temperatures are plausible. The

aperture efficiency of the prototype feed is also shown

in Figure 7. Until 12 GHz, the effieciency is about 40%.

Then the effiency begins to decrease, to 20% at 15 GHz

with the first prototype feed.

Fig. 4 The prototype Iguana feed was deployed to the Kashima

34-meter antenna

6 Future Plans

The upgrade to the Kashima 34-m antenna for wider

bandwidths such as 2.2-18 GHz is on-going. The

Iguana and broadband receiver will be fully installed by this spring, and we will install a new dual

polarization feed by next winter.

Fig. 5 The first light of methanol maser of W3OH. The methanol

lines of 6.7 GHz and 12.2 GHz were simultaneously obtained.

Acknowledgements

The development of Gala-V is supported by a joint

development of National Astronomical Observatory

Japan (NAOJ). It is titled “Development of ultra

broadband system for Kashima 34 meter antenna”.

IVS 2013 Annual Report
348 Takefuji and Ujihara

 0

 100

 200

 300

 400

 500

 0 5 10 15 20

System termperature [K]

Frequency [GHz]

Fig. 6 Gala-V system temperature with the prototype Iguana

feed.

 0

 20

 40

 60

 80

 100

 0 5 10 15 20

Efficiency [%]

Frequency [GHz]

Fig. 7 Gala-V aperture efficiency with the prototype Iguana

feed.

IVS 2013 Annual Report
Onsala Space Observatory – IVS Technology Development

Center Activities during 2013

Miroslav Pantaleev1, Rudiger Haas  ̈

1

, Bhushan Billade1, Leif Helldner1, Karl-Ake Johansson  ̊

1

, Lars Petterson1,

Marianna Ivashina2, Jian Yang2, Carlo Bencivenni2, Oleg Iupikov2

Abstract We give a brief overview on the technical

development related to geodetic VLBI done during

2013 at Onsala Space Observatory.

1 Activities during 2013

Our activities in technical development for VLBI concentrated on the following topics:

• The Onsala Twin Telescope project

• Broadband feeds for VLBI2010 operations

• A dual-polarized S-band system

• A new IF distribution

• A GNSS installation for local-tie measurements.

2 The Onsala Twin Telescope Project

We worked on the preparation of the procurement documents for the Onsala Twin Telescope (OTT). We decided to separate the procurement into two parts. One

part exclusively covers the antennas while the other

part covers the signal chain and electronics. The request for a building permit for the OTT and the request for an exemption from the law for shoreline protection (i.e., a permit for construction within 300 m

from the shoreline) had been submitted to the Kungsbacka municipality already in late 2012. The local au1. Chalmers University of Technology, Department of Earth and

Space Sciences, Onsala Space Observatory

2. Chalmers University of Technology, Department of Signals

and Systems, Antenna Systems

OSO Technology Development Center

IVS 2013 Annual Report

thorities in Kungsbacka community granted both necessary permits in early April 2013. The environmental

department of the next level of authority, the county

of Halland, inspected the planned area for the OTT in

May 2013. The inspector concluded that one of the two

planned telescopes, at the eastern location, could be a

potential disturbance for the local birdlife and in particular disturb the breeding of waders in the area. At

the time of the inspection several birds of the Northern Lapwing (vanellus vanellus) family were seen in

the wetlands. Additionally, the county has plans to include these wetlands into a natural reserve. As a consequence, the county decided in June 2013 to withdraw

the exemption from the law for shoreline protection.

This meant a temporary stop for the whole project,

because now a new location for the second telescope

had to be found. Besides nature protection and local

Fig. 1 An artist’s impression of the planned Onsala Twin Telescope (the two smaller antennas on the right side) together with

the existing 25-m antenna (left). This is the new updated proposal

of December 2013.

349
350 Pantaleev et al.

birdlife, another difficulty is a number of archeological

findings from the Iron Age that need to be protected.

After several discussions with the Kungsbacka authorities, an environmental consultant, and the county’s

archeologist, a suitable location for the second telescope was found. A corresponding request for a building permit and request for an exemption from the law

for shoreline protection was submitted to the Kungsbacka municipality in December 2013. An artist’s impression of the new planned OTT location is presented

in Figure 1.

3 Broadband Feeds for VLBI2010

We continued our collaboration with the Gothenburgbased company Omnisys Instruments. We provided

support for the cryogenic and mechanical design of a

cryostat for the integration of the Eleven Feed and for

further issues related to system integration and tests.

We worked on three parallel tracks of the Eleven feed

development. The first one is the implementation of

a center-bridge connection between the opposite ports

of the Eleven Feed (see Figure 2). This concept was

successfully implemented in a feed for the 0.4–2 GHz

Fig. 2 Geometry of the center-bridge connection for the Eleven

feed. Upper plot: center connection. Lower plot: cross section.

Fig. 3 Reflection coefficients for both polarization ports of the

designed Quad Ridged Feed Horn (QRFH).

Fig. 4 Aperture efficiency (black dashed line) of a prime-focus

reflector antenna system with a subtended semi-angle of 50 degrees fed with the simulated far-field patterns of the designed

Quad Ridged Feed Horn (QRFH). Also shown are (black solid

line) corresponding results published by [1] which are based on

measured patterns.

range. Currently we are investigating different fabrication approaches and technologies to implement this solution for the VLBI2010 frequency range. The second

development track was the implementation of a novel

balun design. This will allow, together with the previously mentioned bridge, reduction of the number of

ports from eight to four. The third track is a novel idea

of designing the dipole array pattern that will give the

ability to control the beam shape and make the feed

tunable for a given F/D.

We also worked on the design of a Quad Ridged

Feed Horn (QRFH). The CST model was used to study

how shaping of the tapers of the ridges, feeding point,

IVS 2013 Annual Report
OSO – IVS Technology Development Center 351

back-short and other parameters of the design affect

the S11 and beam shape. The study was extended to

optimize the performance for the 2–12 GHz band. Figure 3 depicts the reflection coefficient of the final design and Figure 4 the feed efficiency in a prime focus

reflector. The same figure shows for comparison the efficiency of the QRFH design described in [1]. As seen,

the achieved performance is quite close to that reported

in the article. So far there is no decision about fabrication of a prototype to measure beam patterns.

4 A Dual-polarization S-band System

The currently used S-band receiver has one single circular polarization channel while the X-band receiver

has both circular polarizations. To prepare for future

mixed-mode observations with dual-polarized VGOS

systems, we decided to upgrade the S-band receiver to

dual circular polarization, too. One Low Noise Amplifier (LNA) was purchased from the Spanish company

TTI. The cryogenic box accommodating the LNAs for

X- and S-band was modified to integrate the new polarization channel and the new S-band LNA (see Figure 5). Gain and noise of the LNA are presented in Figure 6.

Fig. 5 Interior of the cryogenic box for two polarizations (S- and

X-band).

The performance of the receiver (excluding the

warm part) was verified in the lab, and the receiver

was installed back on the telescope in November 2013.

A septum polarizer was designed for S-band and is

Fig. 6 Gain and noise of the new LNA for S-band.

Fig. 7 CAD drawing presenting the view towards the focal plane

of the 20-m antenna with the tertiary mirror for S-band, the new

design of the horn, and the waveguide for S-band.

Fig. 8 Cross-section of the polarizer for S-band.

currently being manufactured. The waveguide for

S-band was re-designed to accommodate a polarizer

and room temperature waveguide couplers for noise

IVS 2013 Annual Report
352 Pantaleev et al.

and phase calibration signals. Figure 7 depicts a

drawing of the focal plane of the 20-m telescope with

the tertiary reflector for S-band and the new design of

the horn and waveguides for S-band. A cross-section

of the polarizer for S-band is shown in Figure 8. The

plan is to install the new waveguides and polarizer for

S-band in March 2014 and to perform on-sky testing

prior to CONT14.

5 Development of a New IF Distribution

After several months of parallel recordings with the

analog Mark IV backend and the digital DBBC, and

after extensive evaluation, we decided in mid 2013 to

finally phase-out the Mark IV rack and to replace it

with a second DBBC. A corresponding second DBBC

unit was ordered in September 2013 and is expected

to be delivered in April 2014. To be able to include

it quickly into the VLBI system, a new IF distribution unit was developed. This new IF distribution is

flexible and computer-controlled. It allows full flexibility to connect the receivers used for geodetic VLBI

on the 20-m telescope, or the receivers used for astronomical VLBI on the 20-m or 25-m telescope, to either

of the two DBBC units in various configurations. Extensive preparations were performed to minimize the

down-time that will be caused by decommissioning the

Mark IV-rack and installing the second DBBC.

6 A New GNSS Installation on the 20-m

Telescope for Local-tie Measurements

Two GNSS antennas were mounted on each side of

the prime reflector of the 20-m telescope at the height

of the telescope elevation axis. Special gimbal mounts

with counterweights were constructed to keep the

GNSS antennas in the horizontal plane at all times,

independently of the elevation angle of the 20-m

telescope. The GNSS antennas are connected with

coaxial cables to a pair of GNSS receivers inside the

Cassegrain cabin of the 20-m telescope. The recorded

data are downloaded automatically from the receivers

via TCP/IP.

7 Future Plans

We have started a design study for the installation of a

4–12.25 GHz receiver front-end on our 20-m antenna.

The system will extend the bandwidth of the current

S/X system used for IVS observations. An additional

advantage of this 4–12.25 GHz front-end is that it can

be used not only for IVS sessions but also for C- and Xband observations for EVN. The horn will be designed

by BAE Systems Australia Ltd. Preliminary results for

the expected aperture efficiency of this horn are shown

in Figure 9. The cryogenic frond-end will use an OrthoMode transducer from CSIRO, Australia and LNAs of

the Gothenburg-based company LNF. As part of the

study we will investigate the possibility of using the

horn with the current S-band tertiary, thus maintaining

compatibility with the S/X band legacy systems. The

plan is to complete the design study by the middle of

2014 and to decide on manufacturing and telescope installation shortly afterwards, so that the system would

be available on the telescope by the end of 2014.

Fig. 9 Preliminary results for the aperture efficiency of the 4–

12.25 GHz horn for the Onsala 20-m telescope.

References

1. A. Akgiray, S. Weinreb, W. Imbriale, and C. Beaudoin.

Circular Quadruple-Ridged Flared Horn Achieving NearConstant Beamwidth Over Multioctave Bandwidth: Design

and Measurements. IEEE Transactions on Antennas and

Propagation, 61(3), 1099–1108, 2013.

IVS 2013 Annual Report
Bibliography

Bibliography

1 Introduction

The following bibliography compiles papers that were

published in the field of geodetic and astrometric VLBI

during the year 2013. There is no distinction between

peer-reviewed, reviewed, or proceedings publications.

This list is by no means exhaustive.

2 Geodetic and Astrometric VLBI

Publications of 2013

W. ALEF, A. NOTHNAGEL, S. BERNHART, A.

BERTARINI, L. LA PORTA, A. MUSKENS  ̈ , H.

ROTTMANN: “Status and future plans for the

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VLBI Service for Geodesy and Astrometry 2012

Annual Report, edited by K. D. Baver, D. Behrend

and K. L. Armstrong, NASA/TP-2013-217511,

150–153, 2013.

IVS 2013 Annual Report

T. ARTZ, A. NOTHNAGEL, L. LA PORTA: “VLBI

Observations of Geostationary Satellites”. In: Proceedings of the 21st Meeting of the European VLBI

Group for Geodesy and Astrometry, edited by N.

Zubko and M. Poutanen, ISBN: 978-951-711-296-

3, 217–222, 2013.

S. BACHMANN AND M. LOSLER  ̈ : “Activities and

Products at IVS combination center at BKG”.

In: Proceedings of the 21st Meeting of the European VLBI Group for Geodesy and Astrometry,

edited by N. Zubko and M. Poutanen, ISBN:

978-951-711-296-3, 169–174, 2013.

S. BACHMANN, M. LOSLER  ̈ , R. HEINKELMANN,

M. GERSTL: “BKG/DGFI Combination Center

Annual Report 2012”. In: International VLBI

Service for Geodesy and Astrometry 2012 Annual

Report, edited by K. D. Baver, D. Behrend and K.

L. Armstrong, NASA/TP-2013-217511, 245–248,

2013.

D. BAEK, S. YI, H. OH, S. HAN: “Korea Geodetic VLBI Station, Sejong”. In: International VLBI

Service for Geodesy and Astrometry 2012 Annual

Report, edited by K. D. Baver, D. Behrend and K.

L. Armstrong, NASA/TP-2013-217511, 135–138,

2013.

C. BARACHE AND S. LAMBERT: “Paris Observatory

(OPAR) Data Center”. In: International VLBI Service for Geodesy and Astrometry 2012 Annual Report, edited by K. D. Baver, D. Behrend and K.

L. Armstrong, NASA/TP-2013-217511, 231–233,

2013.

K. BAVER AND J. GIPSON: “Refining the Uniform

Sky Strategy for IVS-INT01 Scheduling”. In: Proceedings of the 21st Meeting of the European VLBI

Group for Geodesy and Astrometry, edited by N.

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IVS 2013 Annual Report

IVS Information

IVS Terms of Reference

1 Summary

1.1 Charter

The International VLBI Service for Geodesy and Astrometry (IVS) is an international collaboration of organizations which operate or support Very Long Baseline Interferometry (VLBI) components. IVS provides

a service which supports geodetic and astrometric work

on reference systems, Earth science research, and operational activities. IVS is a Service of the International

Association of Geodesy (IAG) and of the International

Astronomical Union (IAU).

1.2 Objectives

IVS fulfills its charter through the following objectives:

1. foster and carry out VLBI programs. This is accomplished through close coordination of the participating organizations to provide high-quality VLBI

data and products.

2. promote research and development activities in all

aspects of the geodetic and astrometric VLBI technique.

3. advance the education and training of VLBI participants through workshops, reports, and other means.

4. support the integration of new components into

IVS.

5. interact with the community of users of VLBI products. IVS represents VLBI in the Global Geodetic

IVS 2013 Annual Report

Observing System (GGOS) of the IAG and interacts closely with the International Earth Rotation

and Reference Systems Service (IERS).

In support of these objectives, IVS coordinates

VLBI observing programs, sets performance standards for VLBI stations, establishes conventions

for VLBI data formats and data products, issues

recommendations for VLBI data analysis software,

sets standards for VLBI analysis documentation, and

institutes appropriate VLBI product delivery methods

to ensure suitable product quality and timeliness.

IVS coordinates its activities with the astronomical

community because of the dual use of many VLBI

facilities and technologies for both astronomy and

astrometry/geodesy.

1.3 Data Products

VLBI data products contribute uniquely to these important activities:

• defining and maintaining the celestial reference

frame,

• monitoring universal time (UT1), and

• monitoring the coordinates of the celestial pole (nutation and precession).

These results are the foundation of many scientific and practical applications requiring the use of an

accurate quasi-inertial reference frame, such as highprecision positioning, navigation, and timing. In addition IVS provides a variety of VLBI products with

differing applications, timeliness, detail, and temporal

resolution, such as:

369
370 IVS Terms of Reference

• all components of Earth orientation parameters,

• terrestrial reference frame,

• baseline lengths, and

• tropospheric parameters.

All VLBI data and products are publicly available

in appropriate formats from IVS Data Centers.

1.4 Research

The IVS data and products are used for research in

many areas of geodesy, geophysics, and astronomy,

such as:

• UT1 and polar motion excitation over periods of

hours to decades,

• solid Earth interior research (e.g., mantle rheology,

anelasticity, libration, and core modes),

• characterization of celestial reference frame

sources and improvements to the frame,

• tidal variations (solid Earth, oceanic, and atmospheric),

• improvements in the terrestrial reference frame, especially in the scale,

• climate studies (e.g., sea level change, deglaciation,

and water vapor),

• regional and global geodynamics, and

• general relativity.

To support these activities, there are ongoing research efforts to improve and extend the VLBI technique in areas such as:

• instrumentation, data acquisition, and correlation,

• data analysis techniques,

• spacecraft tracking and navigation (Earth-orbiting

and interplanetary), and

• combination of VLBI data and results with other

techniques.

2 Permanent Components

IVS acquires, correlates, and analyzes VLBI data to

produce geodetic, astrometric, and other results that are

archived and publicized. IVS accomplishes its objectives through the following permanent components:

• Network Stations,

• Operation Centers,

• Correlators,

• Analysis Centers,

• Data Centers,

• Technology Development Centers, and

• Coordinating Center.

2.1 Network Stations

The IVS observing network consists of high performance VLBI stations.

• Stations may either be dedicated to geodesy or have

multiple uses (including astronomical observations

or satellite tracking applications).

• Stations comply with performance standards for

data quality and operational reliability specified by

the Directing Board.

• Stations provide local tie information, timing and

meteorological data to the IVS Data Centers.

• VLBI data acquisition sessions are conducted by

groups of Network Stations that may be distributed

either globally or over a geographical region.

2.2 Operation Centers

The IVS Operation Centers coordinate the routine operations of specific networks. Operation Center activities include:

• planning network observing programs,

• supporting the network stations in improving their

performance,

• generating the detailed observing schedules for use

in data acquisition sessions by IVS Network Stations, and

• posting the observing schedule to an IVS Data Center for distribution and archiving.

IVS Operation Centers follow guidelines from the

Coordinating Center for timeliness and schedule file

formats.

IVS 2013 Annual Report
IVS Terms of Reference 371

2.3 Correlators

The IVS Correlators process raw VLBI data. Their

other tasks are to:

• provide timely feedback to the Network Stations

about data quality,

• jointly maintain the geodetic/astrometric community’s media pool and transport,

• manage electronic data transfer,

• make processed data available to the Data Centers,

and

• regularly compare processing techniques, models,

and outputs to ensure that data from different Correlators are identical.

2.4 Analysis Centers

The IVS coordinates VLBI data analysis to provide

high-quality products for its users. The analyses are

performed by:

• Operational Analysis Center,

• Associate Analysis Centers,

• Special Analysis Centers for Specific Observing

Sessions, and

• Combination Centers.

All Analysis Centers maintain and/or develop appropriate VLBI analysis software.

Operational Analysis Centers are committed to producing results to the specifications of the IVS Analysis

Coordinator and always on schedule to meet IVS requirements. In addition, Operational Analysis Centers

may produce Earth orientation parameters, station coordinates, and source positions in regular intervals.

Operational Analysis Centers place their final

results in IVS Data Centers for dissemination to

researchers and other users. They adhere to IVS

recommendations for the creation of high-quality

products and their timely archiving and distribution.

Any deviations that an Operational Analysis Center

makes from IVS recommendations are properly

documented. Operational Analysis Centers provide

timely feedback about station performance. In addition

to these regular services, Operational Analysis Centers

may also perform any task of an Associate Analysis

Center.

Associate Analysis Centers are committed to regularly submit specialized products using complete series or subsets of VLBI observing sessions. The analysis is performed for specific purposes as recognized

by the Directing Board, such as exploitation of VLBI

data for new types of results, investigations of regional

phenomena, reference frame maintenance, or special

determinations of Earth orientation parameters. The

Associate Analysis Centers place their final results in

IVS Data Centers for dissemination to researchers and

other users. They adhere to IVS recommendations for

the creation of high-quality products and their timely

archiving and distribution. Any deviations that an Associate Analysis Center makes from IVS recommendations are properly documented.

Special Analysis Centers for Specific Observing

Sessions have responsibility for ongoing series-related

investigations of one or more existing session types.

They perform detailed and comparative analyses of

each session of a series within a reasonable time after

correlation. In addition, they report deficits and technical complications to the observing sites, the correlators,

and to the schedulers as well as to the IVS Network and

Analysis Coordinators.

Combination Centers are committed to produce

combination results from the individual submissions

of the Operational Analysis Centers as official IVS

products. For this purpose they monitor the quality of

the submissions. The official IVS products include,

but are not limited to, EOP time series derived from

session-based results for 24-hour network sessions and

one-hour Intensive sessions. Combination Centers also

contribute to the generation of the official IVS input

to International Terrestrial Reference Frame (ITRF)

computations. The combination work is done in a

timely fashion and in close cooperation with the IVS

Analysis Coordinator.

2.5 Data Centers

The IVS Data Centers are repositories for VLBI observing schedules, station log files, data and products.

Data Centers may mirror other Data Centers to make

the distribution and maintenance of data more efficient

and reliable.

• Data Centers are the primary means of distributing

VLBI products to users.

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372 IVS Terms of Reference

• Data Centers work closely with the Coordinating

Center and with the Analysis Centers to ensure that

all the information and data required by IVS components are quickly and reliably available.

Data Centers provide the following functions:

• receive and archive schedule files from Operation

Centers,

• receive and archive log files and ancillary data files

from the Network Stations,

• receive and archive data products from the Analysis

Centers, and

• provide access and public availability to IVS data

products for all users.

2.6 Technology Development Centers

The IVS Technology Development Centers contribute

to the development of new VLBI technology for improvement of the VLBI technique. They:

• investigate new equipment and approaches,

• develop, test, and document new hardware,

firmware, and software for operations,

• assist with deployment, installation, and training

for any new approved technology, and

• maintain and support operational equipment.

2.7 Coordinating Center

The IVS Coordinating Center is responsible for coordination of both the day-to-day and the long-term activities of IVS, consistent with the directives and policies

established by the Directing Board. Specifically, the

Coordinating Center monitors, coordinates, and supports the activities of the Network Stations, Operation

Centers, Correlators, Data Centers, Analysis Centers,

and Technology Development Centers. The Coordinating Center works closely with the Technology Coordinator, the Network Coordinator, and the Analysis Coordinator to coordinate IVS activities.

The primary functions of the Coordinating Center

are to:

• coordinate observing programs approved by the Directing Board,

• create and maintain the master schedule of observing sessions in coordination with IVS Network Stations and astronomical observing programs,

• foster communications among all components of

the IVS,

• coordinate the best use of community resources,

• develop standard procedures for IVS components,

• organize training in VLBI techniques,

• organize workshops and meetings, including IVS

technical meetings,

• produce and publish reports of activities of IVS

components,

• maintain the IVS information system and archive

all documents, standards, specifications, manuals,

reports, and publications,

• coordinate IVS outreach and educational activities,

• provide liaison with the IAU, IAG, GGOS, IERS,

and other organizations, and

• provide the Secretariat of the Directing Board.

2.8 Becoming a Permanent Component

IVS will accept proposals at any time to become a permanent component. Such proposals will be reviewed

for approval by the Directing Board.

3 Coordinators

Specific IVS activities regarding network data quality,

products, and technology are accomplished through the

functions performed by three coordinators: a Network

Coordinator, an Analysis Coordinator, and a Technology Coordinator.

3.1 Network Coordinator

The IVS Network Coordinator is selected by the Directing Board from responses to an open solicitation to

all IVS components. The Network Coordinator represents the IVS Network Stations on the Directing Board

and works closely with the Coordinating Center. The

Network Coordinator is responsible for stimulating the

maintenance of a high quality level in the station operIVS 2013 Annual Report
IVS Terms of Reference 373

ation and data delivery. The Network Coordinator performs the following functions:

• monitors adherence to standards in the network operation,

• participates in the quality control of the data acquisition performance of the network stations,

• tracks data quality and data flow problems and suggests actions to improve the level of performance,

and

• coordinates software development for station control and monitoring.

The Network Coordinator works closely with the

geodetic and astronomical communities who are using

the same network stations for observations. The Network Coordinator takes a leading role in ensuring the

visibility and representation of the network stations.

3.2 Analysis Coordinator

The IVS Analysis Coordinator is selected by the Directing Board from responses to an open solicitation to

the IVS Analysis Centers. The Analysis Coordinator

is responsible for coordinating the analysis activities

of IVS and for stimulating VLBI product development

and delivery. The Analysis Coordinator performs the

following functions:

• fosters comparisons of results from different VLBI

analysis software packages and different analysis

strategies,

• encourages documentation of analysis and combination software,

• participates in comparisons of results from different

space geodetic techniques,

• monitors Analysis Centers’ products for high quality results and for adherence to IVS standards and

IERS Conventions,

• ensures that IVS analysis and combination products from all Analysis Centers are archived and are

available to the scientific community, and

• supervises the formation of the official IVS products specified by the IVS Directing Board.

The Analysis Coordinator plays a leadership role in

the development of methods for generation and distribution of VLBI products so that the products reach the

users in a timely manner. The Analysis Coordinator interacts with GGOS and the IERS and promotes the use

of VLBI products by the broader scientific community.

The Analysis Coordinator works closely with the astronomical communities who are using some of the same

analysis methods and software.

3.3 Technology Coordinator

The IVS Technology Coordinator is selected by the Directing Board from responses to an open solicitation to

the IVS Technology Development Centers. The Technology Coordinator performs the following functions:

• stimulates advancement of the VLBI technique,

• maintains awareness of all current VLBI technologies and ongoing development,

• coordinates development of new technology among

all IVS Technology Development Centers,

• encourages technical compatibility with the astronomical community,

• encourages and oversees development of VLBIrelated technical standards,

• coordinates the distribution of and access to technical documents and standards, and

• helps promulgate new technologies to the IVS community.

The Technology Coordinator works closely with

the astronomical community, both to maintain technical compatibility between the geodetic and astronomical communities and to take advantage of technology

development activities in the astronomical community.

4 Directing Board

4.1 Roles and Responsibilities

The Directing Board sets objectives, determines policies, adopts standards, and sets the scientific and operational goals for IVS. The Directing Board exercises

general oversight of the activities of IVS including

modifications to the organization that are deemed appropriate and necessary to maintain efficiency and reliability. The Directing Board may determine appropriate actions to ensure the quality of the IVS products.

IVS 2013 Annual Report
374 IVS Terms of Reference

The Directing Board will receive and review proposals for non-IVS research programs that request IVS

resources.

4.2 Membership

The Directing Board consists of representatives of the

IVS components, members at-large, appointed members, and ex officio members. The members are:

Representatives of IVS Components (see below):

• Correlators and Operation Centers representative

(1)

• Analysis and Data Centers representatives (2)

• Networks representatives (2)

• Technology Development Centers representative

(1)

Elected by the Directing Board upon recommendation from the Coordinating Center (see below):

• Members at large (3)

Selected by Directing Board upon review of proposals from IVS Member Organizations:

• Coordinating Center Director

• Network Coordinator

• Analysis Coordinator

• Technology Coordinator

Appointed members:

• IAU representative

• IAG representative

• IERS representative

Through a reciprocity agreement between IVS and

IERS, the IVS serves as the VLBI Technique Center

for IERS, and as such its designated representative(s)

serve on the IERS Directing Board. In turn, the IERS

Directing Board designates a representative to the IVS

Directing Board. This arrangement is to assure full cooperation between the two services.

Total number: 16

The members appointed by IAU, IAG, and IERS

are not subject to institutional restrictions.

The six members who are the representatives of

the IVS components are elected by the IVS Associate

Members. All elected members serve staggered fouryear terms once renewable.

At-large members are intended to ensure representation on the Directing Board of each of the components of IVS and to balance representation from as

many countries and institutions and IVS interests as

possible. At-large members serve two-year terms once

renewable.

A Directing Board member who departs before the

end of his/her term is replaced by a person selected by

the Directing Board. The new member will serve until the next official elections. The position will then be

filled for a full term.

An individual can only serve two consecutive full

terms on the Board in any of the representative and

at-large positions. Partial terms are not counted to this

limit. After serving two consecutive full terms, an individual becomes eligible again for a position on the

Board following a two-year absence.

The three Coordinators are selected by the Directing Board on the basis of proposals from IVS Member Organizations. On a two-thirds vote the Directing

Board may call for new proposals for any Coordinator

when it determines that a new Coordinator is required.

Coordinators are encouraged to give at least six months

notice before resigning.

4.3 Elections

Election of Board members from the IVS components

shall be conducted by a committee of three Directing

Board members, the chair of which is appointed by the

chair of the Directing Board. The committee solicits

nominations for each representative from the relevant

IVS components. For each position, the candidate who

receives the largest number of votes from the Associate

Members will be elected. In case of a tie the Directing

Board will make the decision.

4.4 Chair

The chair is one of the Directing Board members and is

elected by the Board for a term of four years with the

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IVS Terms of Reference 375

possibility of reelection for one additional term. The

chair is the official representative of IVS to external

organizations.

4.5 Decisions

Most decisions by the Directing Board are made by

consensus or by simple majority vote of the members

present. In case of a tie, the chair decides how to proceed. If a two-thirds quorum is not present, the vote

shall be held later by electronic mail. A two-thirds vote

of all Board members is required to modify the Terms

of Reference, to change the chair, or to replace any of

the members before their normal term expires.

4.6 Meetings

The Directing Board meets at least annually, or more

frequently if meetings are called by the chair or at the

request of at least three Board members. The Board

will conduct periodic reviews of the IVS organization

and its mandate, functions, and components.

5 Definitions

5.1 Member Organizations

Organizations that support one or more IVS components are IVS Member Organizations. Individuals associated with IVS Member Organizations may become

IVS Associate Members.

5.2 Affiliated Organizations

Organizations that cooperate with IVS on issues of

common interest, but do not support an IVS component, are IVS Affiliated Organizations. Affiliated Organizations express an interest in establishing and maintaining a strong working association with IVS to mutual benefit. Individuals affiliated with IVS Affiliated

Organizations may become IVS Corresponding Members.

5.3 Associate Members

Individuals associated with organizations that support

an IVS component may become IVS Associate Members. Associate Members take part in the election of the

incoming members of the Directing Board representing

the IVS components.

5.4 Corresponding Members

IVS Corresponding Members are individuals who express interest in receiving IVS publications, wish to

participate in workshops or scientific meetings organized by IVS, or generally are interested in IVS activities. Ex officio Corresponding Members are the following:

• IAG Secretary General

• Chair of GGOS

• President of IAG Commission 1 – Reference

Frames

• President of IAG Commission 3 - Earth Rotation

and Geodynamics

• President of IAU Division I – Fundamental Astronomy

• President of IAU Commission 8 – Astrometry

• President of IAU Commission 19 – Rotation of the

Earth

• President of IAU Commission 31 – Time

• President of IAU Commission 40 – Radio Astronomy

• President of URSI Commission 52 – Relativity in

Fundamental Astronomy

• President of URSI Commission J – Radio Astronomy

Individuals are accepted as IVS Corresponding

Members upon request to the Coordinating Center.

Last modified: 23 September 2011

IVS 2013 Annual Report
Links to Additional IVS Information

This page provides links to information about the

individuals and groups that support IVS. Member

organizations are organizations that support one or

more permanent components. Permanent components

are groups that formally commit to provide support

in one of six categories: coordination of network

operations (Operation Centers), collection of VLBI

data (Network Stations), processing of raw data (Correlators), archival and distribution of data and products

(Data Centers), analysis of data and generation of

products (Analysis Centers), and development of new

technology (Technology Development Centers).

Information Category Link

Associate Members

(listed alphabetically by last name) ivscc.gsfc.nasa.gov/about/org/members/assoc name.pdf

(listed alphabetically by their organization’s country) ivscc.gsfc.nasa.gov/about/org/members/assoc org.pdf

Permanent Components

Network Stations http://ivscc.gsfc.nasa.gov/about/org/components/ns-list.html

Operation Centers http://ivscc.gsfc.nasa.gov/about/org/components/oc-list.html

Correlators http://ivscc.gsfc.nasa.gov/about/org/components/co-list.html

Data Centers http://ivscc.gsfc.nasa.gov/about/org/components/dc-list.html

Analysis Centers http://ivscc.gsfc.nasa.gov/about/org/components/ac-list.html

Technology Development Centers http://ivscc.gsfc.nasa.gov/about/org/components/td-list.html

Member Organizations http://ivscc.gsfc.nasa.gov/about/org/members/memberorgs.html

Affiliated Organizations http://ivscc.gsfc.nasa.gov/about/org/members/affilmemberorgs.html

IVS 2013 Annual Report

Associate Members are individuals that are associated

with a member organization and have been granted Associate Member status. Associate Members generally

support IVS by participating in the activities of one or

more components.

Affiliated organizations cooperate with IVS on

matters of common interest but do not support a

component.

376