National Aeronautics and Space Administration

International VLBI Service for Geodesy and Astrometry

International VLBI Service for Geodesy and Astrometry

NASA/TP-2008-214162

2007 Annual ReportInternational VLBI Service for Geodesy and Astrometry NASA/TP-2008-214162

IVS Coordinating Center

NASA Goddard Space Flight Center

Code 698

Greenbelt, MD 20771

2007 Annual Report

http://ivscc.gsfc.nasa.gov

ivscc@ivscc.gsfc.nasa.gov

phone: 301-614-5939

fax: 301-614-6522

Edited by 

D. Behrend and K.D. Baver

IVS Coordinating Center IVS www.nasa.gov May 2008

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Preface

This volume of reports is the 2007 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 2007 Annual Report documents the work of the IVS components for the calendar

year 2007, our ninth 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 (described below), the contents of this Annual Report

also appear on the IVS web site at

http://ivscc.gsfc.nasa.gov/publications/ar2007

This book and the web site are organized as follows:

• The first section contains general information about IVS, a map showing the location of the

components, information about the Directing Board members, and the annual report of the

IVS Chair.

• 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 2007.

• The last section includes reference information about IVS: the Terms of Reference, the lists of

Member and Affiliated organizations, the IVS Associate Member list, a complete list of IVS

components, the list of institutions that contributed to this report, and a list of acronyms.

iii

Table of Contents

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

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

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

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

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

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

IVS Coordination ................................................... ............ 11

Coordinating Center Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Analysis Coordinator Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Network Coordinator Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

IVS Technology Coordinator Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Network Stations ................................................... ............ 31

Badary Radio Astronomical Observatory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Fortaleza Station Report for 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Goddard Geophysical and Astronomical Observatory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Hartebeesthoek Radio Astronomy Observatory (HartRAO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Hobart, Mt. Pleasant, Station Report for 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49

Kashima 34-m Radio Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

Kashima and Koganei 11-m VLBI Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Kokee Park Geophysical Observatory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Matera CGS VLBI Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

The Medicina Station Status Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

VERA Geodetic Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Noto Station Status Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Ny- ̊Alesund 20 Metre Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

German Antarctic Receiving Station (GARS) O’Higgins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

The IVS Network Station Onsala Space Observatory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Sheshan VLBI Station Report for 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Simeiz VLBI Station—New Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Svetloe Radio Astronomical Observatory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

JARE Syowa Station 11-m Antenna, Antarctica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Geodetic Observatory TIGO in Concepci ́on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Tsukuba 32-m VLBI Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Nanshan VLBI Station Report for 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Westford Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Fundamentalstation Wettzell - 20m Radiotelescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Observatorio Astron ́omico Nacional – Yebes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Zelenchukskaya Radio Astronomical Observatory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Operation Centers ................................................... .......... 125

The Bonn Geodetic VLBI Operation Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

CORE Operation Center Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

NEOS Operation Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

v
Correlators ................................................... .................. 133

The Bonn Astro/Geo Mark IV Correlator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

Haystack Observatory VLBI Correlator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

IAA Correlator Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

VLBI Correlators at Kashima . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

Tsukuba VLBI Correlator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

Washington Correlator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

Data Centers ................................................... ................ 159

BKG Data Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

CDDIS Data Center Summary for the 2007 IVS Annual Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Italy INAF Data Center Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

Data Center at NICT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

Paris Observatory (OPAR) Data Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

Analysis Centers ................................................... ............ 175

Geoscience Australia Analysis Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

Bordeaux Observatory Analysis Center Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

Matera CGS VLBI Analysis Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

DGFI Analysis Center Annual Report 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

FFI Analysis Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

The BKG/IGGB VLBI Analysis Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

GSFC VLBI Analysis Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

MIT Haystack Observatory Analysis Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

IAA VLBI Analysis Center Report 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .204

Vienna IGG Special Analysis Center Annual Report 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

Italy INAF Analysis Center Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

JPL VLBI Analysis Center Report for 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

IVS Analysis Center at Main Astronomical Observatory of National Academy of Sciences of Ukraine 218

Analysis Center at National Institute of Information and Communications Technology . . . . . . . . . . . . . . . 220

Paris Observatory Analysis Center OPAR: Report on Activities, January - December 2007 . . . . . . . . . . 224

The IVS Analysis Center at the Onsala Space Observatory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228

PUL IVS Analysis Center Report 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

SHAO Analysis Center 2007 Annual Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

U.S. Naval Observatory VLBI Analysis Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

USNO Analysis Center for Source Structure Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242

Technology Development Centers ........................................... 245

Canadian VLBI Technology Development Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247

FFI Technology Development Center - Software Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

GSFC Technology Development Center Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

Haystack Observatory Technology Development Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253

Technology Development Center at NICT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257

The IVS Technology Development Center at the Onsala Space Observatory . . . . . . . . . . . . . . . . . . . . . . . . . .261

Bibliography ................................................... ................ 265

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267

vi
IVS Information ................................................... ............. 283

IVS Terms of Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

IVS Member Organizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

IVS Affiliated Organizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296

IVS Associate Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

IVS Permanent Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308

Addresses of Institutions of Authors Contributing to this Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312

List of Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .318

vii

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,

2. geophysical and astrometric research and operational 

activities.

3. To promote research and development activities 

in all aspects of the geodetic and astrometric VLBI 

technique.

4. 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

• 28 Network Stations, acquiring high performance VLBI 

data,

• 3 Operation Centers, coordinating the activities of a 

network of Network Stations,

• 6 Correlators, processing the acquired data, providing 

feedback to the stations and providing processed data 

to analysts,

• 6 Data Centers, distributing products to users, providing storage and archiving functions,

• 21 Analysis Centers, analyzing the data and producing 

the results and products,

• 7 Technology Development Centers, developing new 

VLBI technology,

• 1 Coordinating Center, coordinating daily and long term 

activities.

Altogether

• 72 Permanent Components, representing 37 institutions in 17 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

perform ance feedback

data bases

Coordinating

Center

Analysis

Centers

Analysis

Coordinator

Network

Stations

Operation

Centers

Technology

Development

Centers

Users

Network

Coordinator

Technology

Coordinator

• Publications

• W eb Site

• Master Schedule

raw data 10-20G b/s

(m agnetic tapes,disks,ftp)

perform ance feedback

correlated data bases

analyzed results and products

schedules

products for EO P,TRF,CRF

Data

Centers

Correlators

IAG IAU IVS Directing

Board
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

Vienna University of Technology Austria

Centro de Rádio Astronomia e Aplicações 

Espaciais

Brazil

Space Geodynamics Laboratory Canada

Geodetic Survey Division, Natural 

Resources Canada

Canada

Dominion Radio Astrophysical 

Observatory

Canada

Canadian Space Agency Canada

Universidad de Concepción Chile

Universidad del Bío Bío Chile

Instituto Geográphico Militar of Chile Chile

Chinese Academy of Sciences China

Observatoire de Paris France

Observatoire 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

Istituto di Radioastronomia INAF Italy

Agenzia Spaziale Italiana Italy

Geographical Survey Institute Japan

National Institute of Information and 

Communications Technology

Japan

National Astronomical Observatory of 

Japan

Japan

National Institute of Polar Research Japan

Norwegian Defence Research 

Establishment

Norway

Norwegian Mapping Authority Norway

Astronomical Institute of St.-Petersburg 

University

Russia

Institute of Applied Astronomy Russia

Pulkovo Observatory Russia

Hartebeesthoek Radio Astronomy 

Observatory

South 

Africa

Instituto Geografico Nacional Spain

Chalmers University of Technology Sweden

Organization Country

Main Astronomical Observatory, National Academy of Sciences, KievUkraine

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

Korea Astronomy Observatory Korea

Joint Institute for VLBI in Europe (JIVE) Netherlands

Westerbork Observatory Netherlands

Auckland University of Technology New Zealand

National Radio Astronomy Observatory USA
4

IVS Components by Country

Country Qty.

Australia 2

Austria 1

Brazil 1

Canada 1

Chile 1

China 3

France 3

Germany 8

Italy 7

Japan 12

Norway 3

Russia 7

South Africa 1

Spain 1

Sweden 3

Ukraine 2

USA 16

Total 72

A complete list of IVS Permanent

Components is in the IVS Information

section of this volume.

O'Higgins

NEOS

GGAO

Canadian VLBI

Haystack

USNO

GSFC

JPL

Kokee Park

O'Higgins

Fortaleza

NEOS

GGAO

Canadian VLBI

Haystack

USNO

GSFC

JPL

Kokee Park

Network Station

Operation Center

Correlator

Data Center

Analysis Center

Technology Development Center

Coordinating Center

Network Station

Operation Center

Correlator

Data Center

Analysis Center

Technology Development Center

Coordinating Center

TIGO

IVS Component Map
5

Syowa

Hartebeesthoek

Seshan

Nanshan

Shanghai

Kashima 11

Koganei

Tsukuba

NICT

Mizusawa

Kashima34

TU Vienna

Yebes

Noto

Wettzell

Simeiz

DGFI

INAF

Matera

BKG

Svetloe

IAA

MAO

AIStPbU

Bordeaux

Paris

FGS(BKG,IGGB)

IGGB

FFI Onsala

Ny Ålesund

Seshan

Nanshan

Badary

Shanghai

Kashima 11

Koganei

Tsukuba

NICT

Mizusawa

GA

Kashima34

Medicina

TU Vienna

Yebes

Noto

DGFI Wettzell

INAF

Matera

BKG

Svetloe

IAA

MAO

AIStPbU

Bordeaux

Paris

FGS(BKG,IGGB)

IGGB

FFI Onsala

Ny Ålesund

Syowa

Hartebeesthoek

Simeiz

Hobart

Zelenchukskaya
6

NAME: Hayo Hase

AFFILIATION: Bundesamt für 

Kartographie und Geodäsie/

TIGO, Germany/Chile

POSITION: Networks 

Representative

TERM: Feb 2007 to Feb 2011

NAME: Dirk Behrend

AFFILIATION: NVI, Inc./Goddard Space Flight Center, USA

POSITION: Coordinating Center 

Director

TERM: ex officio

NAME: Harald Schuh

AFFILIATION: Vienna University 

of Technology, Austria

POSITION: Chair and IAG 

Representative

TERM: ex officio

NAME: Yoshihiro Fukuzaki

AFFILIATION: Geographical 

Survey Institute, Japan

POSITION: Networks

Representative

TERM: Feb 2007 to Feb 2011

NAME: Ed Himwich

AFFILIATION: NVI, Inc./Goddard Space Flight Center, USA

POSITION: Network

Coordinator

TERM: permanent

NAME: Kerry Kingham

AFFILIATION: U.S. Naval

Observatory, USA

POSITION: Correlators

and Operation Centers

Representative

TERM: Feb 2007 to Feb 2011

NAME: Andrey Finkelstein

AFFILIATION: Institute of

Applied Astronomy, Russia

POSITION: At Large Member

TERM: Feb 2007 to Feb 2009

IVS Directing Board

NAME: Patrick Charlot

AFFILIATION: Bordeaux Observatory, France

POSITION: IAU Representative

TERM: ex officio
7

NAME: Xiuzhong Zhang

AFFILIATION: Shanghai Astronomical Observatory, China

POSITION: At Large Member

TERM: Sept 2007 to Feb 2009

NAME: Chopo Ma

AFFILIATION: NASA Goddard 

Space Flight Center, USA

POSITION: IERS Representative

TERM: ex officio

NAME: Alan Whitney

AFFILIATION: Haystack

Observatory, USA

POSITION: Technology

Coordinator

TERM: permanent

NAME: Arthur Niell

AFFILIATION: Haystack

Observatory, USA

POSITION: Analysis and Data 

Centers Representative

TERM: Feb 2005 to Feb 2009

NAME: Oleg Titov

AFFILIATION: Geoscience Australia, Australia

POSITION: At Large Member

TERM: Sept 2007 to Feb 2009

NAME: Ray Norris

AFFILIATION: Australia Telescope 

National Facility, Australia

POSITION: FAGS Representative

TERM: ex officio

NAME: Axel Nothnagel

AFFILIATION: University of 

Bonn, Germany

POSITION: Analysis

Coordinator

TERM: permanent

NAME: William Petrachenko

AFFILIATION: National

Resources Canada, Canada

POSITION: Technology Development Centers Representative

TERM: Feb 2005 to Feb 2009
8

Harald Schuh,

Vienna University of Technology

At the 17th Directing Board Meeting, held on February 

24, 2007, Wolfgang Schlüter’s term as IVS Chair came 

to an end and I was elected as the new chair. Wolfgang 

had served two four-year terms spanning the whole time 

since the inception of the IVS. I would like to take this 

opportunity to express my sincere gratitude and warm 

thanks to Wolfgang, who did an excellent job during all 

those first years for the IVS. He considerably contributed 

to the strong role that IVS plays today within the IAG 

and IAU.

With the 2007 Annual Report the IVS components report 

about their progress and activities, which were conducted 

during the service’s ninth year of existence. I would like to 

thank the IVS Associate Members for their contributions 

over the course of the year, in particular for providing their 

reports in time. Timely appearance of the Annual Report 

is always an ambitious goal and is highly appreciated for 

maintaining this volume as a real information exchange 

tool for the community and related groups. I thank the 

editors for the timely release.

In 2007, IVS observing activities could be even extended 

as compared to the previous year, a fact that in view 

of the limited resources can be attributed to optimized 

coordination by the Coordinating Center and strong support from all components. I would like to thank the staff 

of the Coordinating Center who bear much responsibility 

and carry a heavy burden for the entire service activities. Day-to-day work is carried out continuously by the 

Network Stations, the Correlators, the Data Centers, 

and the Analysis Centers and is the basis for the regular 

provision of precise IVS products. In the following I would 

like to emphasize those activities performed in 2007 that 

go beyond the normal work load.

IVS Contribution to the Global Geodetic Observing 

System (GGOS)

Integration and combination in the framework of the Global 

Geodetic Observing System (GGOS) of the International 

Association of Geodesy will be the main challenge for the 

international geodesy in the coming decades. GGOS will 

go beyond the integration of geodetic space techniques 

(VLBI, SLR, GNSS, DORIS) as it includes also techniques 

measuring terrestrial gravity, the global Earth gravity field, 

sea level, and even the magnetic field. Thus, a consistent 

combination of all geometric and physical techniques 

will eventually be required. GGOS, which just recently 

has been changed from an IAG project to a permanent 

IAG component, will play an essential role in helping to 

solve environmental and societal problems. Many open 

questions related to global change, sea level rise, or the 

prevention of natural hazards need precise reference 

frames and exact geodetic measurements. VLBI can give 

a critical contribution to GGOS by its relation to a quasiinertial celestial reference frame and its unique ability to 

measure long-term UT1-UTC and precession/nutation. 

One of the IVS main tasks in 2007 was to establish the 

IVS as an efficient and reliable partner within GGOS and 

also to increase the awareness in the public and in the 

scientific community about the importance of VLBI.

VLBI2010 and the VLBI2010 Committee (V2C)

The VLBI2010 Committee (V2C), which was established 

by the IVS Directing Board in September 2005, is tasked 

with promoting the ambitious goals set by the VLBI2010 

report “VLBI2010: Current and Future Requirements for 

Geodetic VLBI Systems” released by IVS Working Group 

3. I am very pleased to know that the VLBI2010 Committee, chaired by Bill Petrachenko, has been extremely busy 

in 2007 with frequent telecons and additional face-to-face 

meetings. The results provided so far are very useful and 

will be summarized in a report with recommendations 

that can be used as benchmark for new VLBI systems. 

Members of the V2C are (alphabetically) Dirk Behrend, 

Johannes Böhm, Brian Corey, Rüdiger Haas, Yasuhiro 

Koyama, Dan MacMillan, Zinovy Malkin, Arthur Niell, 

Bill Petrachenko, and Gino Tuccari. I would like to thank 

them all for taking over the responsible leading role in the 

realization of the VLBI2010 visions.

The V2C is tasked with providing the specifications for the 

next generation VLBI system. Part of the VLBI2010 plan is 

that also non-VLBI2010 antennas (legacy or new) can still 

take part in geodetic VLBI sessions. Thus, antennas that 

are slower than the envisaged VLBI2010 antennas and/or 

that are observing on X-band and S-band only will still be 

important contributors to the IVS observing program. Right 

now several countries plan to develop or purchase new 

VLBI systems and they need the specifications. I highly 

appreciate that Geoscience Australia (GA), Australia; 

Auckland University of Technology (AUT), New Zealand; 

Korea Astronomy & Space Science Institute (KASI) and 

National Geographic Information Institute (NGII), Korea; 

and the Bundesamt für Kartographie und Geodäsie (BKG), 

Germany started activities to implement new telescopes 

to support the vision of VLBI2010. I would like to congratulate them on these ambitious projects and wish them 

success for the realization in the next years. With the new 

antennas and a possible re-opening of a radio telescope 

at Fairbanks, the global coverage of geodetic VLBI is getting better, but it is still far from being optimal. Thus, ideas 

and proposals for new stations are more than welcome. 

IVS Chair's Report
9

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. 

John Gipson, Chair of this new Working Group (IVS WG 

4), will give a first presentation at the IVS General Meeting 

in Saint Petersburg, Russia (March 2008).

Meeting Events in 2007

In April 2007, the 18th Working Meeting on European 

VLBI for Geodesy and Astrometry (EVGA), the 8th IVS 

Analysis Workshop, and the 2nd IVS VLBI2010 Working 

Meeting were held at the Institute of Geodesy and Geophysics, Vienna University of Technology, Austria. All three 

meetings were successful events with a high number of 

participants. The scientific organization of the meetings 

was performed in close collaboration with the IVS Analysis 

Coordinator and Chair of the EVGA, Axel Nothnagel; the 

local organizing committee was led by Johannes Böhm 

and Jörg Wresnik. 

The 4th IVS Technical Operations Workshop (TOW) was 

held at the Haystack Observatory from April 30–May 3, 

2007. TOW is an important meeting for exchanging experience in operation and for providing information about 

new developments. “Hands-on” training and teaching in 

classes is the key for the success of TOW. It was another 

very useful meeting of this type and I would like to thank 

Ed Himwich, Dirk Behrend, and Heidi Johnson and the 

local organizers at Haystack for their commitment to the 

TOW.

In September 2007, a face-to-face meeting of the VLBI2010 

Committee and the 18th Directing Board Meeting were 

held at the Institute of Geodesy and Geoinformation of 

the University of Bonn, Germany. I take this opportunity to 

thank Axel Nothnagel for making the meetings successful 

and the stay a very pleasant one. In the week directly following these meetings, the 6th International e-VLBI Workshop was held at MPI, Bonn. Many thanks to the Program 

Committee and the LOC, chaired by Walter Alef, who were 

responsible for this very fruitful and efficient meeting. 

Summary information about all IVS events and activities is available in the Newsletters 17, 18, and 19. The 

Newsletter is an excellent means to transfer information 

to everybody. The editor team, Dirk Behrend, Hayo Hase, 

and Heidi Johnson, presented interesting and up-to-date 

information. They once again did an excellent job, which 

is highly appreciated. 

However, VLBI will always be at the top-end, concerning 

the quality of the results but also concerning the costs 

compared, for instance, to GNSS receiving systems. 

Special Issue on Very Long Baseline Interferometry 

of the Journal of Geodesy

In June 2007 a Special Issue on Very Long Baseline 

Interferometry (VLBI) of the Journal of Geodesy (JoG) 

was published with guest editors nominated by the IVS 

(Harald Schuh, Axel Nothnagel, and Chopo Ma). Since the 

establishment of the IVS the coordination of international 

VLBI has significantly improved yielding valuable scientific 

and operational results for the whole community inside and 

outside geodesy. However, the number of relevant scientific publications on VLBI in peer-reviewed journals was 

still rather small, because most of the scientific discussion 

and exchange had been done via the proceedings of international and regional VLBI conferences organized under 

the auspices the IVS. Therefore, it was the right time for a 

Special Issue on VLBI in the Journal of Geodesy for providing information about the state-of-the-art in VLBI research 

to a broader community. After the call for contributions had 

been issued, the editors were pleased to see a strong 

response from the various IVS analysis groups and also 

from various users of VLBI results. Manuscripts, some including new areas of application of the VLBI system, such 

as combination with other geodetic space techniques, 

were submitted by institutions from all over the world. All 

manuscripts went through the standard peer-review process of the Journal of Geodesy, ensuring that the quality 

of the published articles was the same as in a standard 

issue of the JoG. The result was a Special Issue which 

should provide the reader with a better understanding of 

the VLBI technique, the organization of the IVS, as well 

as a variety of scientific applications such as the celestial 

and terrestrial reference frames including investigations 

of the observed radio sources, Earth orientation, and 

atmospheric sciences (troposphere and ionosphere). As 

Chair of the IVS and also on behalf of the editorial team, I 

would like to thank all the contributors to the Special Issue 

as well as the reviewers, who made it possible to realize 

this document within a reasonable time frame.

IVS Working Group 4 on “VLBI Data Structures” Established

In September 2007 a new IVS Working Group was established as a response to a strong need of new, common 

VLBI data structures. This 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 
10

IVS Chair's Report Continued

Changes in the Directing Board in 2007

The elections of the two Networks Representatives as well 

as of the Correlators and Operation Centers Representative for the term 2007 to 2011 were held in December 2006. 

Yoshihiro Fukuzaki (GSI, Japan) and Hayo Hase (BKG, 

Germany and TIGO, Chile) were elected to represent the 

IVS Network Stations, and Kerry Kingham (USNO, USA) 

was elected as the Representative of the Correlators and 

Operation Centers. For the at large positions (term 2007 

to 2009) Andrey Finkelstein, Russia; Oleg Titov, Australia; 

and Xiuzhong Zhang, China were elected by the Directing Board in January 2007. In July 2007, the Federation 

of Astronomical and Geophysical Data Analysis Services 

(FAGS) appointed Ray Norris (ATNF Australia) as its 

new representative on the IVS Directing Board. I am very 

pleased that the IVS Directing Board is well balanced in its 

composition with respect to global coverage, with respect 

to component representation, and with respect to a good 

mixture of experienced and young members.
IVS Coordination

NASA Goddard Space Flight Center IVS Coordinating Center

Coordinating Center Report

Dirk Behrend

Abstract

This report summarizes the activities of the IVS Coordinating Center during the year 2007 and

forecasts activities planned for the year 2008.

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 2007

During the period from January through December 2007, the Coordinating Center supported

the following IVS activities:

• Directing Board support: Coordinated, with local committees, two IVS Directing Board

meetings, in Wettzell, Germany (February 2007) and Bonn, Germany (September 2007).

Notes from each meeting were published on the IVS Web site.

• Communications support: Maintained the Web pages, e-mail lists, and Web-based mail

archive files. In June 2007 the e-mail lists were changed so that only submissions from e-mail

list members and white list members are being accepted and distributed. By the end of 2007

all communications services were ported from the previous HP platform to a Linux platform.

• Publications: Published the 2006 Annual Report in spring 2007. Published three editions

of the IVS Newsletter in April, August, and December 2007. All publications are available

electronically as well as in print form.

• 2007 Master Schedule: Generated and maintained the master observing schedule for 2007.

Coordinated VLBI resources for observing time, correlator usage, tapes, and disk modules.

Coordinated the usage of Mark 5 systems at IVS stations and efficient deployment of disk

modules.

• 2008 Master Schedule: Generated the proposed master schedule for 2008 and received approval from the Observing Program Committee.

• Meetings: Coordinated, with the Local Committee, the fourth IVS Technical Operations

Workshop, held at Haystack Observatory in April/May 2007. Chaired the Program Committee for the meeting. Coordinated, with the Local Committee, the fifth IVS General Meeting,

IVS 2007 Annual Report 13
IVS Coordinating Center NASA Goddard Space Flight Center

to be held in Saint Petersburg, Russia in March 2008. Chaired the Program Committee for

the meeting.

• Observing Program Committee (OPC): Coordinated meetings of the OPC to monitor the

observing program, review problems and issues, and discuss changes.

Figure 1. Logo of the fourth IVS Technical Operations Workshop (TOW).

3. Staff

The staff of the Coordinating Center is drawn from individuals who work at Goddard. The

staff and their responsibilities are:

Name Title Responsibilities

Dirk Behrend Director Web site and e-mail system maintenance,

Directing Board support, meetings, publications, session Web pages monitoring

Cynthia Thomas Operation Manager Master schedule (current year), resource management and monitoring, meetings 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, editorial assistance, session Web pages

support and scripts

14 IVS 2007 Annual Report
NASA Goddard Space Flight Center IVS Coordinating Center

4. Plans for 2008

The Coordinating Center plans for 2008 include the following:

• Maintain IVS Web site and e-mail system; implement new station pages.

• Publish the 2007 Annual Report (this volume).

• Coordinate, with the local committee, the fifth IVS General Meeting to be held in Saint

Petersburg, Russia in March 2008.

• Publish Proceedings of the fifth IVS General Meeting.

• Support Directing Board meetings in 2008.

• Coordinate the 2008 master observing schedule and IVS resources.

• Publish Newsletter issues in April, August, and December.

IVS 2007 Annual Report 15
IVS Analysis Coordinator Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn

Analysis Coordinator Report

A. Nothnagel, S. B ̈ockmann, T. Artz

Abstract

IVS analysis coordination issues in 2007 are reported here. Routine EOP combinations have been

changed to solely using datum-free normal equations as input improving the overall agreement between

analysis centers to 50 – 60 μas in all components.

1. General Issues

The “Eighth IVS Analysis Workshop” was held at the Vienna University of Technology, Vienna, Austria, on April 14, 2007, in connection with the 18th European VLBI for Geodesy and

Astrometry (EVGA) Working Meeting. The workshop was attended by about 40 participants who

enjoyed the hospitality of the Vienna VLBI group.

In his introductory remarks the IVS Analysis Coordinator emphasized that the combination

process of VLBI results with other geometric space geodetic techniques (GNSS, DORIS, and SLR)

is the most important challenge of IVS analysis activities in the current time frame. Without an

improved attitude of the IVS Analysis Centers towards combination requirements and timeliness

issues, the IVS will run into the danger of losing its well earned reputation for state-of-the-art

products.

Further presentations and discussions included topics like cable calibration, master analysis

documentation, pole tide model, 256 Mb/s vs. 1 Gb/s recording, reference temperatures and

pressure, current status of the OCCAM software, combination of Intensives, atmospheric refraction

issues, implementation of P03 precession, singular value decomposition and cluster analysis, post

VLBI solution tools, as well as an introduction to the Working Group on ICRF2. A number of

these topics do require more efforts on an international level and all IVS Analysis Centers are asked

to volunteer for a more active role in specific aspects of the analysis chain. The large number of

individual problem areas cannot be handled efficiently by a few individuals alone. This is the

reason why many topics are still on the “To do” list and progress lags behind expectations.

2. IVS Operational Data Analysis and Combination

On January 1, 2007, a new combination process for the two IVS EOP series (rapid and quarterly

solutions) has been made operational. Routine combinations of IVS are now being made exclusively

on the basis of datum-free normal equations in SINEX format. In 2007, five IVS Analysis Centers

(BKG, DGFI, GSFC, IAA, and USNO) contributed to the IVS combined products by providing

input in the correct format. 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 the five IVS Analysis Centers are

available. The SINEX file submissions should not be later than 48 hours after the correlation

is completed. A Web page is automatically updated which states the timeliness of the latest

submissions of the R1 and R4 sessions. As can be seen on this Web page, the timeliness requirement

is exceeded too often for various reasons in logistics and personnel.

For the quarterly solution, updated every three months, almost all available data of 24-hour

sessions from 1984 onwards are used. Since this series is designed for EOP determinations, those

16 IVS 2007 Annual Report
Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn IVS Analysis Coordinator

sessions are excluded which are observed with networks of limited extension or which are scheduled

for a different purpose like radio source monitoring.

The advantage of the new combination strategy is that one common terrestrial reference frame

(e.g. ITRF2005) is applied after the combined datum-free normal matrix is generated. Thus, it is

guaranteed that an identical datum is used in the combination process for all input series. After

datum definition the combined system of normal equations is solved (inverted) and the full set of

EOP (pole components, UT1–UTC, and their time derivatives as well as two nutation offsets in dψ,

dε w.r.t. the IAU2000A model) are extracted. These results are added to the two EOP time series

in the IVS EOP Exchange format, the rapid solution file (e.g., ivs07r1e.eops) and the quarterly

solution file (e.g., ivs07q4e.eops). Companion files containing the nutation offsets in the X, Y

paradigm are routinely generated through a standard transformation process (e.g., ivs07r1X.eops,

ivs07q4X.eops). The weighted RMS differences between the individual IVS Analysis Centers and

the combined products have been reduced from roughly 80–100 μas to 50–60 μas in all components.

On the IVS Analysis Coordinator’s Web page additional information about the series, the residuals

of the individual contributions w.r.t. the combined solution as well as comparisons with IGS and

IERS EOP results are provided routinely.

At the same time the combined SINEX files (datum-free normal equations) are also available on

the Web for further combination with other techniques. At present, this is done on an experimental

basis only, but the IERS Analysis Coordinator is strongly pushing towards such a routine process.

3. Comparisons of Long-term Station Position Time Series

As part of the quality assessment for the IVS combined products, long-term time series of station positions of each individual IVS Analysis Center, derived from the submitted normal equations,

have been compared with each other. Through this, systematic offsets in the height component

of up to 1 cm have been detected between solutions analysed with the VLBI analysis software

packages OCCAM and CALC/SOLVE. In order to find the reason for these discrepancies several

models used in both software packages have been compared in close cooperation with the VLBI

group at DGFI (Deutsches Geod ̈atisches Forschungsinstitut, M ̈unchen). It turned out that the

systematic offsets were mainly caused by differences in the pole tide model. In the CALC/SOLVE

solutions, a model for the annual mean pole was used, which was not in agreement with the IERS

Conventions 2003. Therefore, all analysis centers using CALC/SOLVE reprocessed their solutions

with the conventional pole tide model according to the IERS Conventions 2003 and most of the discrepancies disappeared. Since the IVS input to ITRF2005 was affected by the same inconsistency,

the ITRF2005 may be affected by this oversight, though not to the full extent.

4. Personnel

Table 1. Personnel at the IVS Analysis Coordinator’s office

Sarah B ̈ockmann +49-228-733563 boeckmann@uni-bonn.de

Axel Nothnagel +49-228-733574 nothnagel@uni-bonn.de

Thomas Artz +49-228-733563 thomas.artz@uni-bonn.de

IVS 2007 Annual Report 17
Network Coordinator NVI, Inc./GSFC

Network Coordinator Report

Ed Himwich

Abstract

This report includes an assessment of the network performance in terms of lost observing time for

the 2007 calendar year. Overall, the observing time loss was about 11.4%. A table of relative incidence

of problems with various subsystems is presented. The most significant causes of loss were antenna

reliability (accounting for about 34.6%), receiver problems (14.9%), unclassified problems (14.9%), rack

problems (11.4%), and RFI (10.4%). There are prospects for Korea, India, and New Zealand to start

contributing to IVS. New antennas are being purchased by Australia and New Zealand. The current

situation for the handling of correlator clock adjustments by the correlators, which directly impacts

UT1-UTC estimates from VLBI data, is reviewed. This is found generally to be a stable continuation

of last year’s results.

1. Network Performance

The network performance report is based on correlator reports for experiments in calendar

year 2007. This report includes the 135 24-hour experiments that had detailed correlator reports

available as of March 4, 2008. Results for 35 experiments were omitted because they were correlated

at the VLBA, they have not been 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 is not as detailed as from Mark IV correlators. The experiments that have

not been correlated yet include mostly RD, JD, and T2 experiments from the second half of the

year, as well as some OHIG experiments. The experiments without reports on the IVS data

centers include all experiments processed by the Haystack correlator (10 plus one that has not

been correlated yet). In summary, roughly 80% of the scheduled experiments for 2007 are included

in this report.

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 one-third of the nominal time and therefore only recording one-third of the expected bits.

In a similar fashion, poor pointing can be converted into an equivalent lost sensitivity and then

equivalent lost bits. Poor recordings can be 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 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. For individual station days, the results should probably not be assumed

to be accurate at better than the 5% level.

18 IVS 2007 Annual Report
NVI, Inc./GSFC Network Coordinator

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 are beyond the control of the station, such as weather and power failures. Instead

the results should be viewed in aggregate as an overall evaluation of how much of the data the

network is collecting as a whole. 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 about twice the average loss of

observing time. This approximation is described in the Network Coordinator’s section of the IVS

2001 Annual Report.

For the 135 experiments from 2007 examined here, there are 907 station days or about 6.7

stations per experiment on average. Of these experiment days about 11.4% (or about 103 days)

of the observing time was lost. For comparison to earlier years, 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

* The percentage applies to a subset

of the 1999-2000 experiments.

The lost observing time for 2007 was less than for 2006. It is not clear whether the year-to-year

variations in lost observing time reflect real changes in the performance level or simply variations

due to inaccuracies in the analysis method. It does seem, however, that despite the approximations

in the analysis method, the calculated observing time loss has been running fairly consistently at

the 12-14% level for several years. It should be noted that in the CONT05 experiments in 2005,

where a special effort was made to achieve high reliability at some of the most reliable stations

in the network, an observing time loss of only 4.0% was achieved for 165 scheduled station days.

If the observing time losses are converted into VLBI data yield losses, then 2007 had about 23%

VLBI data loss, 2006 about 27%, 2005 about 29%, 2004 about 25%, and 2003 about 29%.

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 counterproductive. 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 overinterpreted. 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 2007 Annual Report 19
Network Coordinator NVI, Inc./GSFC

be some interest in attempting to “game” the analysis methods to improve the individual results.

Consequently, only summary results are presented here.

For the purposes of this report, the stations were divided into two categories: (A) those that

were included in 9 or more network experiments among those analyzed here, and (B) those in 6

or fewer. 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 data loss from

both groups this year were about equal.

There are 17 stations in the 9-or-more experiment category. Twelve stations observed in 44

or more experiments. Of the 17, 10 successfully collected data for approximately 90% of their

expected observing time. Four more stations collected 75% or more. Three more stations collected

more than 50% of their data. Two stations of the 17 collected only slightly more than 50% of

the scheduled data. These statistics are somewhat better than last year. The top 11 stations

are heavily exercised and quite reliable from year to year. The three lowest yielding stations had

particular problems that have been or are being addressed.

There are 17 stations in the 6-or-fewer experiment category. The range of lost observing time

for stations in this category was 0%-72%. The median success rate was about 3.6%, much better

than last year. Overall the stations in this category lost about 10.5% of the 60 station days they

observed; about 7% of the total analyzed were lost. It is notable that the performance for the

stations that were in the fewest experiments has been comparable to the more heavily used stations

for two years in a row now.

Although the results are not being reported for individual stations, a few stations deserve

special recognition for how much their data collection improved from the previous year. Five

stations improved the percentage of data they collected by more than 5%. These stations are

Matera, Onsala, Ny- ̊Alesund, Noto, and Westford.

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 break-down (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 five years of data sorted by decreasing loss in 2007.

Table 2. Percentage Data Lost by Sub-system

Sub-System 2007 2006 2005 2004 2003

Antenna 34.6 19.0 24.4 32.9 17.8

Receiver 14.9 20.8 24.2 18.0 25.2

Unknown 14.9 4.0 3.3 10.1 12.6

Rack 11.4 16.3 5.1 6.8 5.0

RFI 10.4 11.6 6.2 5.0 9.3

Miscellaneous 7.6 18.0 8.0 8.0 6.0

Recorder 4.6 3.3 8.9 11.1 10.9

Shipping 1.0 0.0 0.2 1.4 6.1

Software 0.4 0.1 0.5 0.1 0.1

Clock 0.3 4.9 14.5 0.5 3.4

Operations 0.0 2.0 4.7 6.1 3.6

The categories in Table 2 are rather broad and require some explanation, which is given below.

20 IVS 2007 Annual Report
NVI, Inc./GSFC Network Coordinator

Antenna This category includes all antenna problems including mis-pointing, antenna control

computer failures, and mechanical break-downs of the antenna.

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.

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, weather, and errors in

the observing schedule provided by the Operation Centers. Starting with 2006, this category

also includes errors due to tape operations at the stations that were forced to use tape

because either they didn’t have a disk recording system or they did not have enough media.

There were very few tape related losses (0.5% overall) in 2007, reflecting the almost complete

absence of tape use. This category is dominated by power and weather 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.

Rack This category includes all failures that could be attributed to the rack (DAS) including the

formatter and BBCs.

Receiver This category includes all problems related to the receiver including out-right failure,

loss of sensitivity because the cryogenics failed, design problems that impact the sensitivity,

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 disk recording systems and network

transfer of data. Starting with 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 or

amplitude variations in individual channels, particularly at S-band.

Shipping This category includes data that could not be correlated 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 data 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.

From the results it can be seen that antenna and receiver problems together account for almost

50% of the losses. This is larger than the last couple of years and is dominated by antenna problems.

For 2007 the stations with significant antenna problems include Zelenchukskaya, Fortaleza, Svetloe,

and Matera.

IVS 2007 Annual Report 21
Network Coordinator NVI, Inc./GSFC

Stations with significant receiver problems include Fortaleza, Ny- ̊Alesund, and Zelenchukskaya.

Most of these problems are in the category of reliability problems with the cryogenics, power supplies, and amplifiers. Some stations suffered from an unexplained roll-off in the X-band bandpass,

which has been included in this category. Fortaleza is notable for having problems in reliability

and roll-off.

The “Miscellaneous” category is smaller than last year and more like the results of earlier years.

This is primarily due to a reduction in losses due to power outages.

The “Rack” category was smaller this year than last. The primary cause of losses in this

catagory is due to the observed video BW being smaller than scheduled. Three stations: Fortaleza,

Shanghai, and Badary had problems with this. However, the situation has now been corrected at

all three stations.

The “RFI” category loss level is similar to last year’s, which is larger than results from previous

years. The higher level is primarily due to the fact that Matera, the station with the most severe

RFI problems, was able to observe more since their antenna has been fixed.

The “Clock” category represents less loss than previous years. This is primarily due to the fact

that there were no major Maser failures and that the consistency of clock offset reporting from the

stations has improved.

The “Recorder” category is down significantly from previous years primarily because almost

all recording is done on disk and the problems with the few tape recordings that were made are

reported now in the “Miscellaneous” category. The decrease in data loss due to recorder operations

from about 11% to about 4% probably represents the “disk dividend” we have been hoping to get

as tape use is curtailed.

2. New Stations

The station at Badary began observing in 2007. There are prospects for new stations on several

fronts. Both Australia and New Zealand are in the process of obtaining new antennas, three and

one, respectively. Korea is planning to build one antenna primarily for geodesy. There is also

interest in using the Korean VLBI Network (KVN), which will consist of three stations intended

primarily for astronomy, for geodesy. There is interest in India in building a network of four

telescopes that would be useful for geodesy. Many of these antennas may become available for use

in the next few years. Efforts are being made to ensure that these antennas will be compatible

with VLBI2010.

3. Clock Offsets

As noted in the Network Coordinator’s reports for the last few years, it is important to develop

consistent procedures for handling the clock offsets during the correlation process. Stations measure

the offset between their formatter and the UTC time provided by GPS. The correlators typically

apply a small, few μseconds or less, adjustment to the measured offsets in order to align the data

to get fringes. If the adjustments are not applied in a consistent fashion by all correlators, a

corresponding error will be made in the UT1-UTC parameter adjustments. This will affect the

quality of IVS UT1-UTC products at the level of the inconsistency in the adjustments. This could

be corrected during the data analysis, but currently no analysis package does this. It would require

a significant amount of bookkeeping to add this feature now.

22 IVS 2007 Annual Report
NVI, Inc./GSFC Network Coordinator

The Network Coordinator’s report for 2002 recommended that the correlators develop a consistent table of adjustments for correcting the local measurements of the formatter offsets relative

to GPS. This would remove a source of correlator-to-correlator and experiment-to-experiment

variability in the UT1-UTC results. It was suggested that in developing this table the applied

correction for Kokee should be artificially set to zero (when Kokee uses the VLBA formatter; when

they use a Mark IV, the correction should be increased to about 0.4 μseconds). Although not

strictly correct, it is a simple approach and will maintain a level of consistency with old data,

much of which was processed by WACO with a correction of zero for Kokee. However, compensation will have to be made for the “true” adjustment when an effort is made to align the ICRF

and ITRF at this level. It was also recommended in the report from 2002 that a reference for the

clock rate should be established at the same time.

Significant progress was made in 2005 in implementing these recommendations. The calendar

year 2006 is the first one in which this approach was applied to all experiments. The greatly

improved results obtained that year are reported in the 2006 Network Coordinator’s Report. This

has continued for 2007. The offset adjustment for Wettzell in 2007 is shown in Figure 1. The

scatter of these measurements is very good for Mark IV correlators (Bonn, GSI, and WACO).

Generally the variation is at the 0.1 μsecond level, but there are few larger outliers (a couple off

the scale of the figure as well) for the Bonn correlator. It is not known if these outliers are due to

typographic errors or if the adjustments for these experiments were larger than expected. They

should be investigated. In any event, the results are greatly improved compared to years before

2006 where the adjustments were scattered over a range at least 10 times as large.

It is interesting to note that the adjustments for Wettzell used by the GSI (K5) correlator

are biased by about 1-2 μseconds, including some jumps, compared to those used by the Mark

IV correlators. If this is correct, it would bias UT1-UTC and add jumps to the estimates from

GSI correlated experiments compared to Mark IV correlated experiments. As it happens, the

GSI correlator is currently used only for “K” type Intensives and domestic Japanese 24-hour

experiments. The UT1-UTC precision of these experiments is much less than that of the 24-hour

international experiments, around 10-20 μseconds for the “K” type Intensives compared to a few

μseconds for R1 and R4 experiments. Consequently, this bias does not significantly impact the

results. In 2007 it was realized that the K5 correlator does not include the effect of the clock

offset and rate in its calculation of the time-tags and delays that it produces [Y. Koyama (NICT),

personal communication]. Thus the correlator clock model is not currently reflected in the UT1

results for the K5 correlator. This will be corrected in the future.

A further issue is how stable the UT1 rate measurements are. This depends on the accuracy

of the correlator models for the Maser (and associated station electronics) rates for the observing

stations. The desired accuracy of the IVS Working Group 2 report was for 0.3-0.5 μseconds/day.

This translates into a clock rate of about 3.5e-12 to 5.8e-12. It would be desirable to have the

correlator clock models consistent at a level 10% of that, 3e-13, or better. It turns out that it is

possible to determine the station rates at about the level required from the formatter offset values

recorded during 24-hour experiments.

A plot of the Correlator Clock Rate Model for Wettzell for 2007 using this approach is shown

in Figure 2. It is difficult to see on the scale of the plot, but the clock rates used by the Mark

IV correlators (Bonn, GSI, and WACO) vary at about the desired level, about 2e-13 (4e-13 peakto-peak, i.e., simplifying by saying that the peak-to-peak is about twice the RMS). This is in line

with last year’s results and is an improvement of a factor of two over previous years. The rates

IVS 2007 Annual Report 23
Network Coordinator NVI, Inc./GSFC

Figure 1. Wettzell Correlator UTC Clock Adjustments

for Wettzell used by the GSI correlator vary by about 1.7e-11 (peak-to-peak). These exceed the

desired level by a factor of about three (not 30, as incorrectly reported in last year’s report). As

with UT1-UTC estimates for GSI, this is probably not an issue, given the lower precision of the

experiments processed by this correlator. However, this should probably be improved. The reason

for the scatter in the rates used by the GSI correlator is that they are determined from the clock

offsets measured during the short span of data collected in the K Intensives [Y. Koyama (NICT),

personal communication]. This explains the larger range of the values. The origin of the systematic

nature of the rates is not clear, but presumably it is related to some systematic effect that is being

sampled by the clock offset measurements. As mentioned previously the correlator clock model is

not being taken into account in the results of the K5 correlator. But this is planned for the future.

Another area of concern is that different recording systems may require different adjustments.

There is a difference between Mark IV and VLBA formatters of about 0.4 μseconds [K. Kingham

(USNO), private communication]. This was accounted for when Kokee changed from using VLBA

to Mark IV formatters. A value of 0.26 μseconds was measured between the K5 and the Mark

IV formatters, with K5 later than Mark IV [Y. Koyama et al., Timing Offset of the K5/VSSP

System, IVS NICT TDC News No. 26, p. 6-8]. This compares well to the value that has been

empirically determined from processing of K5 data at Mark IV correlators [K. Kingham (USNO),

private communication].

It is also important to consider whether there are offsets between different recording rates

within a given recording system. It was recently discovered that there appears to be a 8 μsecond

24 IVS 2007 Annual Report
NVI, Inc./GSFC Network Coordinator

Figure 2. Wettzell Correlator Clock Rate Model

offset for the Mark IV formatter when the tape data rate is 18 MHz as compared to other lower

data rates [D. Smythe, Timing Offset of the Mark IV Formatter, Haystack Observatory Mark 5

Memo #047]. This offset essentially affects only 1024 Mb/s recordings and 512 Mb/s 32 track

recordings. Otherwise the Mark IV formatter is known to not have an offset between different

data rates [D. Smythe (Haystack Observatory), private communication].

The difference between correlators must also be considered. The VLBA correlator has moved

to the same relative offset used by the Mark IV correlators; i.e. Kokee with a VLBA formatter is

0 μseconds [C. Walker (NRAO), private communication]. However, we don’t know if the VLBA

correlator has an offset relative to the Mark IV correlators. We must also consider whether there

is an offset of the K5 correlator relative to the Mark IV. This will have to be investigated before

experiments that yield more precise estimates of UT1, typically 24-hour experiments with long

baselines, are processed with the K5 correlator.

IVS 2007 Annual Report 25
IVS Technology Coordinator Report MIT Haystack Observatory

IVS Technology Coordinator Report

Alan Whitney

Abstract

The efforts of the Technology Coordinator in 2007 included the following areas: 1) support of work

to implement a new geodetic VLBI system as outlined in the IVS Working Group 3 “VLBI2010” study,

2) continued development and deployment of e-VLBI, 3) 6th annual e-VLBI workshop held at MPI

in Bonn, Germany, and 4) TOW workshop at Haystack Observatory. We will briefly describe each of

these activities.

1. VLBI2010 Progress

Progress continues towards the goal of a next generation geodetic VLBI system. Some of the

highlights include:

1.1. Development of the First Demonstration Broadband System

A collaboration of Haystack Observatory, NASA/GSFC and Honeywell implemented the first

demonstration broadband system on the 5 m MV3 antenna at NASA/GSFC. The system has the

following characteristics:

1. A commercial dual linear polarization feed to cover ∼2-13 GHz, followed by two LNAs. The

feed and LNAs are cooled to ∼20 K.

2. Optical transmission of the full RF bandwidth to ‘up/down converters’ (UDCs) in the base

of the antenna. Each UDC selects an arbitrary 500 MHz slice of the RF band and translates

it to the proper Nyquist zone for sampling.

3. A digital backend (DBE1) which accepts up to four 500 MHz-wide IFs and separates each into

fifteen adjacent 32 MHz-wide channels using polyphase filter band (PFB) technology, though

only every other channel is recorded. In the full-up demo system, four dual polarization IFs

of 500 MHz width each will be processed through eight PFBs, each IF creating 1 Gbps of

data for a total of 8 Gbps.

4. The data are recorded on Mark 5B+ recorders, each capable of supporting 2 Gbps. Current

experiments use two Mark 5B+ systems at each site for a total of 4 Gbps. The full-up demo

system will use four Mark 5B+ systems at each site for a total of 8 Gbps at each site.

5. The data are processed on a standard Mark IV correlator slowed down by a factor of 2 from

the real-time rate.

In November 2007 a successful experiment was conducted using a broadband demonstration

system at MV3 (dual linear polarization) and a standard S/X system at Westford (single circular

polarization). Results from this experiment appeared as expected except for some unexplained

phase differences between cross-correlations of different polarization; this phenomenon is being

investigated.

Plans are in progress to also implement the broadband system on the Westford antenna to

allow tests of a single baseline with complete broadband systems on both antennas.

26 IVS 2007 Annual Report
MIT Haystack Observatory IVS Technology Coordinator Report

Figure 1. Fourfit plot of fringes from VLBI2010 demo experiment.

The characteristics of the commercial broadband feed currently being used are non-ideal for this

work, and efforts are underway to have a new dual linear polarization feed designed by Per-Simon

Kildal at Chalmers University, who has designed successful broadband feeds for other frequency

ranges. This work is being partially supported by contributions from our Norwegian colleagues;

others are expected to contribute to this effort as well. A new feed design could be ready within a

year or so. The final VLBI2010 broadband system will broaden the IF bandwidths to 1 GHZ each

and raise the data acquisition rate to at least 16 Gbps using a so-called ‘burst-mode’ technique

where data for each individual scan, which may be 5-10 seconds in length, are buffered to high-speed

electronic memory. Then, while the antenna is slewing for the next ∼30-45 seconds to the next

source, the data are ‘dribbled’ off to a recording or data transmission system at a rate of ∼4 Gbps.

This 4 Gbps rate will be supported by a single Mark 5C system (currently under development) or

an e-VLBI data link at each site. One of the outstanding VLBI2010 system design issues is the

specification and development of a delay/phase calibration sub-system. Work will proceed on this

issue in 2008.

1.2. Antennas for VLBI2010

A 12 m diameter seems to have been pretty much selected for the VLBI2010 application,

although at least two designs have been developed:

1. Patriot Antenna of Albion, Michigan, USA offers a 12 m antenna with an azimuth rate of

5 deg/sec and an elevation rate of 1 deg/sec. Australia and New Zealand have both placed

orders for this antenna with deliveries expected in 2008. Some debate remains regarding

whether these slew speeds are adequate; studies into this subject are still on-going.

2. Wettzell/BKG is developing a high slew speed 12 m antenna for use in their ‘twin-antenna’

project.

IVS 2007 Annual Report 27
IVS Technology Coordinator Report MIT Haystack Observatory

1.3. VLBI2010 Studies

A well-attended VLBI2010 workshop was held on 15 April 2007 in Vienna, Austria in conjunction with the EVGA meeting. Many papers relating to all aspects of VLBI2010 were presented,

and many lively and fruitful discussions took place. In general, there was much enthusiasm and

support for continued work and much interest in the development of demonstration and prototype

hardware and software systems to support the goals of VLBI2010. The next VLBI2010 workshop

will be held in March 2008 in St. Petersburg, Russia.

A number of studies related to VLBI2010 are still underway, some of which are attempting

to determine the necessary minimum antenna slew speeds needed to create an observing program

that will meet the VLBI goal of 1 mm accuracy in 24 hours with 12 m antennas and the associated

data acquisition systems that are contemplated. At present, there are no clear-cut answers, but

the studies do not seem to indicate that higher slew speed antennas are necessarily substantially

better.

2. e-VLBI Development

2.1. New or Enhanced Connections

Additional stations continue to be connected for e-VLBI. Among the notable new connections

are Svetloe and, expected soon, Badary. Among the notable upgraded connections are 10 Gbps

connections at Onsala, Metsahovi, Westford and the Haystack correlator. Wettzell has upgraded

its link to ∼600 Mbps. TIGO has recently upgraded its link to at least 32 Mbps for short periods

of time and is pursuing a more permanent upgrade. Hobart’s connection to the University of

Tasmania has been upgraded to 1 Gbps with new fiber, but the connection from Tasmania to

mainland Australia is still somewhat of a bottleneck. Fiber to the Fortaleza station has been

installed, and Fortaleza’s connectivity to the global network is anticipated soon.

2.2. Continuing Expansion and Development of Routine e-VLBI Data Transfers

MPI now conducts regular e-VLBI transfers of data for which the Bonn correlator is the correlation target. This includes data from Japan, Onsala, Ny- ̊Alesund, and Wettzell. All data recorded

on K5 systems at Tsukuba and Kashima are now transferred either to MPI or Haystack depending on the target correlator. Syowa K5 data are physically shipped to Japan and electronically

transferred to Haystack or MPI. UT1 Intensive data from Wettzell, Japan and Ny- ̊Alesund are

transferred to either MPI or a site near the Washington correlator (where the last couple of km is

currently handled via sneakernet!), depending on the target correlator for the data.

2.3. 6th International e-VLBI Workshop Held at MPI, Bonn, Germany

The 6th International e-VLBI Workshop was hosted by MPI and held 17-18 September 2007

in Bonn, Germany. The workshop was attended by some 60 participants from 15 countries. Presentations at the workshop showed rapid progress in e-VLBI on several fronts. In Europe, the

JIVE EXPReS project continues to connect European astronomical VLBI telescopes in real-time

and conducts regular scientific e-VLBI experiments with up to 5-6 stations at data rates nearing

1 Gbps/station. Australia continues to make rapid progress in connecting its telescopes and has

also developed a software correlator system to support real-time observations. A Japanese-Finnish

28 IVS 2007 Annual Report
MIT Haystack Observatory IVS Technology Coordinator Report

team delivered the database of an Intensive (one hour) session to the analysts only 20 minutes after

the conclusion of the observations. A panel discussion on VSI-E led to a charge to re-invigorate the

VSI-E working group and to finalize the VSI-E specification within a year. Alan Whitney, as chair

of that group, accepted the charge but has since had to pass the baton to Dr. Chester Ruszczyk

of Haystack due to a change in Alan’s position at Haystack Observatory. All presentations from

the Bonn workshop are available at http://www.mpifr-bonn.mpg.de/div/vlbi/6th evlbi/. The next

e-VLBI workshop will be held 16-17 June 2008 in Shanghai, China. We all look forward to another

valuable and stimulating meeting.

3. TOW2007 Workshop at Haystack Observatory

The 4th IVS Technical Operations Workshop (TOW) was held 30 April—3 May 2007 at

Haystack Observatory. The TOW is intended to provide hands-on training and problem resolution in VLBI operations primarily for the technical staff of the stations. The curriculum included

operations and maintenance workshops such as equipment operation and checkout, Mark 5A and

Mark 5B operations, cryogenic system maintenance, RFI identification and mitigation, and general

station troubleshooting. Seminars on such subjects as correlator theory and operations, introduction to Linux, timing systems, phase calibration basics, e-VLBI overview, introduction to the K5

system, and H-maser monitoring and maintenance helped to further inform the participants. And

various lectures on ‘how VLBI works’, science overview, Mark 5 system operation, and impact of

operations on data analysis helped to broaden the view of all attendees. All TOW2007 workshop

presentations are available at http://ivscc.gsfc.nasa.gov/meetings/tow2007/notebook.html.

IVS 2007 Annual Report 29

Network Stations

Institute of Applied Astronomy of Russian Academy of Sciences Badary Station

Badary Radio Astronomical Observatory

Sergey Smolentsev, Roman Sergeev

Abstract

This report provides information about Badary network station: general information, facilities,

staff, present status and outlook.

1. General Information

The Badary Radio Astronomical Observatory (BdRAO) was founded by the Institute of Applied

Astronomy (IAA) as one of three stations of the Russian VLBI network QUASAR [1]. The

sponsoring organization of the project is the Russian Academy of Sciences (RAS). The Badary

Radio Astronomical Observatory is situated in the Burytia Republic (East Siberia) about 130 km

east of Baikal Lake (see Table 1). The geographic location of the observatory is shown on the

IAA RAS [3] Web site. The basic instruments of the observatory are a 32-m radio telescope and

technical systems for doing VLBI observations.

Figure 1. Badary Observatory.

Table 1. Badary Observatory location and address.

Longitude 102◦14′

Latitude 51◦46′

Badary Observatory

Republic Burytia

671021, Russia

sergeev@ipa.nw.ru

IVS 2007 Annual Report 33
Badary Station Institute of Applied Astronomy of Russian Academy of Sciences

2. Technical and Scientific Information

The Badary station equipment includes the following main components: a 32-m radio telescope

equipped with low noise receivers, a frequency and time keeping system with H-masers, a local

geodetic network, a GPS receiver (geodetic) and a GPS/GLONASS K161 receiver (synchronization

of time keeping system), a data acquisition system R1001 [2], Mark 5B and S2 recording terminals,

control computers, a local computer network and technical service systems. An automatic meteorological station WXT510 (Vaisala) has been installed at Badary. The local geodetic network 2 is

adjusted with accuracy 2–3 mm. Characteristics of the radio telescope and other main components

of the station are presented in Tables 2, 3, and 4.

The time and frequency system is composed of two hydrogen maser standards CH1-80 as well as

GPS/GLONASS receivers for preliminary time synchronization with an accuracy of not more than

100 ns. The frequency stability of the H-masers is presented in Table 4. Local VHF oscillators are

locked by a reference signal of 5 MHz and provide 10–20 mW power output signals at frequencies

1.26, 2.02, 8.08, 4.5, and 22.12 GHz. A pulse calibration system includes a pulse generator with

a pulse duration of about 50 ps. The Badary Observatory was connected with main line optical

fiber glass in December 2007.

Table 2. 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 1.5

◦/s

- tracking velocity 1.5

′/s

- acceleration 0.2

◦/s2

Maximum elevation

- velocity 0.8

◦/s

- tracking velocity 1.0

′/s

- acceleration 0.2

◦/s2

Pointing accuracy better than 10′′

Configuration Cassegrain

(with asymmetrical sub-reflector)

Main reflector diameter 32-m

Sub-reflector diameter 4 m

Focal length 11.4 m

Main reflector shape quasi-paraboloid

Sub-reflector shape quasi-hyperboloid

Surface tolerance of main reflector ±0.5 mm

Frequency capability 1.4–22 GHz

Axis offset −11.5 mm

34 IVS 2007 Annual Report
Institute of Applied Astronomy of Russian Academy of Sciences Badary Station

Table 3. Parameters of receivers.

Wave band Frequency range Input noise temperature

13 cm 2.15–2.5 GHz 12 K

3.5 cm 8.2–8.9 GHz 15 K

Table 4. Frequency stability of the CH1-80 H-maser.

Sample time interval (Allan variance)1/2

1 second 3 · 10−13

10 seconds 3 · 10−14

100 seconds 1 · 10−14

1000 seconds 3 − 5 · 10−15

3. Technical Staff

Roman Sergeev — Observatory chief,

Nicolay Mitovin — FS, pointing system controls,

Alexander Seryx — front end and receiver support.

4. Co-location with GPS

A permanent GPS receiver Leica SR520 was installed at Badary during April 2005 (Fig. 2,

Fig. 3).

Figure 2. GPS marker. Figure 3. GPS receiver.

The accuracy of the local geodetic network (LGN) is about 2 mm. However, we still cannot

provide an accurate survey of the VLBI radio antenna. In September 2006 a leveling session was

carried out to check the LGN marker stability.

IVS 2007 Annual Report 35
Badary Station Institute of Applied Astronomy of Russian Academy of Sciences

304 306

310

311

309

307

308

301

312

C

50 m

The LGN includes ten reference points. 304 and 306–309

are ground markers. 301 and

312 are located on the roof

of the laboratory building and

are intended for the installation of GPS/GLONASS and

DORIS antennas. 310 is the

intersection of the radio telescope axes, and 311 is an intermediate marker on the azimuthal platform of the radio

telescope.

Figure 4. Local geodetic network at Badary Observatory.

5. Participation in IVS Observing Programs

In 2007 the Badary station started participating in IVS programs. During 2007 the Badary

IVS station participated in 13 IVS sessions: 10 IVS-R4, 2 EUROPE, and 1 IVS-T2.

6. Outlook

Our plans for the coming year are the following:

• Final adjustment of all radio telescope systems to satisfy VLBI requirements.

• Participation in 56 IVS observing sessions: IVS-R1, IVS-R4, IVS-T2, and EURO.

• Participation in domestic observational programs for obtaining Earth orientation parameters.

• Surveying the local geodetic network.

References

[1] Finkelstein A., Ipatov A., Smolentsev S. Radio Astronomy Observatories Svetloe, Zelenchukskaya and

Badary of VLBI Network QUASAR. In: IVS 2004 General Meeting Proceedings, eds. N. R. Vandenberg,

K. D. Baver, NASA/CP-2004-212255, 2004. pp. 161–165.

[2] Fedotov L., Ivanov D., Ipatov A., Ipatova I., Lavrov A., Kosobokov M., Mikhailov A. Institute of

Applied Astronomy Technology Development Center. In: IVS 2006 Annual Report, eds. D. Behrend,

K. D. Baver, NASA/TP-2007-214151, 2007. pp. 255–258.

[3] http://www.ipa.nw.ru/PAGE/koi8-r/DEPOBSERV/rus.

36 IVS 2007 Annual Report
CRAAM, Universidade Presbiteriana Mackenzie, S ̃ao Paulo Fortaleza

Fortaleza Station Report for 2007

Pierre Kaufmann, A. Mac ́ılio Pereira de Lucena, Claudio E. Tateyama,

Francisco A. Tavares F. da Silva

Abstract

This is a brief report about the activities carried out at Fortaleza geodetic VLBI Station (ROEN:

R ́adio Observat ́orio Espacial do Nordeste), located in Eus ́ebio, CE, Brazil, in 2007. The observing

activities consisted of 90 VLBI sessions and continuous GPS monitoring recordings. The installation

of optical fiber was completed, and the station switched to a 1 Gbit/s high speed network, to be used

in e-VLBI operations.

1. General Information

The R ́adio Observat ́orio Espacial do Nordeste, ROEN, located at INPE facilities in Eus ́ebio,

nearly 30 km east of Fortaleza, Cear ́a 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 1990s. During that time the antenna and instrumental facilities were erected, and it was

the beginning of the 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, Mackenzie Presbyterian University, S ̃ao Paulo, in agreement

with the Brazilian National Space Research Institute, INPE. A new contract was signed in May

2004 between NASA and CRAAM, Mackenzie Presbyterian Institute and University to partially

support the activities at ROEN until 2009. This contract is a consequence of the Agreement of

Cooperation signed between NASA—representing research interests of NOAA and USNO—and

the Brazilian Space Agency, AEB, in 2002. The counterpart of the operational costs, staff, and

support of infrastructure are provided by INPE and by Mackenzie.

2. Component Description

The largest instrument of ROEN is the 14.2 m radio telescope, an alt-azimuth positioner. It is

operated at S- and X-bands, using cryogenic radiometers. The system is controlled by the Field

System, Version 9.9.2. 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 Prof. Pierre Kaufmann, from the

S ̃ao Paulo main office at CRAAM (CRAAE)/Instituto and Universidade Presbiteriana Mackenzie,

IVS 2007 Annual Report 37
Fortaleza CRAAM, Universidade Presbiteriana Mackenzie, S ̃ao Paulo

Figure 1. Fortaleza’s 14.2 m antenna.

receiving scientific assistance from Dr. Claudio E. Tateyama and partial administrative support

from Valdomiro S. Pereira and Neide Gea Escolano. Partial technical assistance is given by staff

from the Itapetinga Radio Observatory near S ̃ao Paulo, also operated by INPE/Mackenzie.

The Fortaleza Station facilities and geodetic VLBI and GPS operations are managed on

site by Dr. A. M. P. de Lucena (CRAAE/INPE), assisted by Eng. Adeildo Sombra da Silva

(CRAAE/Mackenzie), the technicians Avicena Filho (CRAAE/INPE) and Carlos Fabiano B. Moreira (CRAAE/Mackenzie).

4. Current Status and Activities

4.1. VLBI Observations

Fortaleza participated in the following geodetic VLBI experiments, as detailed in the table

below for the year 2007.

Table 1. 2007 session participation.

Experiment Number of Sessions

IVS-R1 28

IVS-R4 45

IVS-T2 03

IVS-CRF 03

IVS-OHIG 07

IVS-R&D 02

IVS-CRMS 03

38 IVS 2007 Annual Report
CRAAM, Universidade Presbiteriana Mackenzie, S ̃ao Paulo Fortaleza

Figure 2. Fortaleza’s station team

4.2. Development and Maintenance Activities in 2007

Considerable attention was given to technical maintenance, especially to the following activities:

1) installation of a new cryogenic system, 2) replacement of video converters for the new Mark IV

VC modules, 3) repairs of the following circuits, modules or systems: Mark III video converters,

Mark III power supplies, and the Mark III IF Distributor module, 4) repairing the UPS system,

5) maintenance of the Web site (http://www.roen.inpe.br) and the local server computer, and 6)

painting the steel structure of the 14.2 m antenna.

4.3. GPS Operations

The IGS network GPS receiver operated regularly at all times during 2007. Data were collected

and uploaded to an IGS/NOAA computer.

4.4. High Speed Network

The installation of fiber and the switch to a high speed 1 Gbits/s network, to be used in e-VLBI

operations, was completed in December 2007. Figure 3 shows details of the connection switch.

Figure 4 illustrates the network fiber path in the Fortaleza metropolitan area. The Fortaleza

VLBI Station is labeled INPE-ROEN.

The Brazilian Research Network (RNP) circuit across the country is shown in Figure 5. There

IVS 2007 Annual Report 39
Fortaleza CRAAM, Universidade Presbiteriana Mackenzie, S ̃ao Paulo

Figure 3. Switch rack for connection to the high speed fiber network.

Figure 4. Fortaleza metropolitan area showing the

high speed optical fiber network.

Figure 5. National RNP fiber optic circuits.

are two options available for connecting to the international optical cables: via Rio de Janeiro or

via Fortaleza.

5. Future Plans

The completed high speed optical network connection will allow ROEN to participate in e-VLBI

experiments. The network is currently being tested.

6. Acknowledgements

These activities have received partial support from NASA, within an agreement with the Brazilian Space Agency (AEB) and a contract with Mackenzie, as part of an agreement between Mackenzie INPE.

40 IVS 2007 Annual Report
NASA Goddard Space Flight Center Goddard Geophysical and Astronomical Observatory

Goddard Geophysical and Astronomical Observatory

Jay Redmond, Mark Evangelista

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 previous

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 radio telescope

for VLBI, an SLR site to include MOBLAS-7, SLR-2000 (development system), a 48” telescope

for developmental two color Satellite Ranging, a GPS timing and development lab, meteorological

sensors and a H-maser. In addition, we are a fiducial IGS site with several IGS / IGSX receivers.

Figure 1. Installation of new wide band dewar on

MV3 antenna.

GGAO is located on the east coast of the United States in Maryland. It is about 15 miles NNE

of Washington D.C. in Greenbelt, Maryland (Table 1).

2. Technical Parameters of the VLBI Antenna at GGAO

The radio telescope for VLBI at GGAO (MV3) was originally built as a mobile or transportable

station. It was previously known as Orion and was part of the original CDP. It is now being used as

a fixed site, having been moved to Goddard and semi-permanently installed here since the spring

of 1991. In the winter of 2002 the antenna was taken off its trailer and permanently installed at

GGAO. The design criteria were:

IVS 2007 Annual Report 41
Goddard Geophysical and Astronomical Observatory NASA Goddard Space Flight Center

• transportability on two tractor trailers utilizing a 5 meter dish size to maximize reception

and mobility considerations,

• setup of the radio telescope within eight hours (although it has been used as a fixed site since

the spring of 1991)

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://www.gsfc.nasa.gov

The technical parameters of the radio telescope are summarized in Table 2.

Table 2. Technical parameters of the radio telescope of GGAO for geodetic VLBI.

Parameter GGAO-VLBI

Owner and operating agency NASA

Year of construction 1982

Diameter of main reflector d 5m

Azimuth range 0 ... 540◦

Azimuth velocity 3

◦/s

Azimuth acceleration 1

◦/s2

Elevation range 0 ... 90◦

Elevation velocity 3

◦/s

Elevation acceleration 1

◦/s2

X-band 8.18 − 8.98 GHz

Receiving feed Cassegrain focus

Tsys 24 K

Bandwidth 800MHz, −2dB

G/T 32.1 dB/K

S-band 2.21 − 2.45GHz

Receiving feed Primary focus

Tsys 19 K

Bandwidth 240MHz, −2dB

G/T 21.2 dB/K

VLBI terminal type Mark IV

Recording media Mark 5A

Field System version 9.10.2

42 IVS 2007 Annual Report
NASA Goddard Space Flight Center Goddard Geophysical and Astronomical Observatory

3. Technical Staff of the VLBI Facility at GGAO

The GGAO VLBI facility gains from the experiences of the Research and Development VLBI

support staff. GGAO is a NASA R&D and data collection facility, operated under contract by

Honeywell Technology Solutions Incorporated (HTSI). Table 3 lists the GGAO station staff that

are involved in VLBI operations.

Table 3. Staff working at the MV3 VLBI station at GGAO.

Name Background Dedication Agency

Jay Redmond Engineering technician 100% HTSI

Skip Gordon Engineering technician 20% HTSI

4. Status of MV3 at GGAO

GGAO participated in the VLBI experiments that are listed in Table 4. In addition to these

scheduled experiments, MV3 participated in several unscheduled experiments for VLBI developmental purposes and various other developmental activities.

Table 4. Participation of GGAO in scheduled VLBI experiments.

Date Experiment

2007-03-13 RDART4

2007-05-15 T2050

MV3 has installed Mark 5 and e-VLBI hardware and continues to test real-time VLBI from

GGAO to Haystack. On January 26, 2007, MV3 recorded two 480MHz bands that covered all

of the X-band IF, with two-bit sampling, for an aggregate data rate of ∼4Gb/s. Two VSI data

streams (each ∼2Gb/s) were recorded on two Mark 5B’s and the data were transferred to the

Haystack correlator via high-speed internet connections. It was also demonstrated, by comparing

to simultaneously recorded Mark IV data, that there appear to be no major sources of signal loss

in the Digital Back End (DBE) system.

MV3 is a major component in the program to demonstrate that the VLBI2010 broadband

delay concept is feasible. In 2007 MV3 participated in two demonstrations. In April the Digital

Back End (DBE) and two Mark 5B+’s were used to demonstrate the high data rate acquisition

components. Data were recorded at 2 Gigabits per second (Gbps) with the standard geodetic S/X

system. Because of the limited bandpasses, the resulting data rates were only 0.9 Gbps at S-band

(the full bandwidth) and 1.6 Gbps at X-band (the upper half of the band). After a successful

fringe test, a six-hour geodetic session was run.

A major modification of MV3 began in October in order to install the prototype VLBI2010

RF system. The geodetic S/X feed, receiver and supporting structure were replaced with a dewar,

constructed by Haystack, containing the broadband Lindgren feed, two low noise amplifiers, and

cryogenic refrigerator. Considerable time was spent trying to understand why the efficiency of

IVS 2007 Annual Report 43
Goddard Geophysical and Astronomical Observatory NASA Goddard Space Flight Center

the new system is lower than expected, but even with this limitation strong fringes were finally

obtained with Westford at X-band in November. This was a major milestone in the VLBI2010

program since it demonstrated one band of the complete broadband signal chain which included

the feed, LNAs, Up-Down converter (UDC), digital back end, Mark 5B+ recorder, and for one

polarization, the use of optical fiber to bring the RF signal from the antenna to the control room.

5. Outlook

In its present configuration, GGAO will mainly support VLBI2010, e-VLBI, and other developmental activities during the upcoming year. Basic plans for 2008 consist of:

1. Continued testing of pre-release versions of PC-FS and new Linux kernel releases.

2. Continued support of Mark 5 and Digital Back End (DBE) hardware development.

3. Continued support of the development and testing of VLBI2010 hardware and software.

4. Continually striving to improve the performance of the entire Mark 5 data collection and

station specific equipment.

MV3 is also the other antenna used with Westford as a test bed for e-VLBI research because of

the high data rate internet connection through GSFC. In 2007 this connection was used to transfer

the data from the VLBI2010 tests soon after the observations, for confirmation of successful fringes.

One of the first projects in 2008 will be an attempt to demonstrate an aggregate data rate of

approximately 2 Gbps in real time by using two 1 Gbps channels.

Haystack is constructing a second dewar for Westford, as well as seven more UDC’s and DBE’s

so that a full 4-band, two polarization system can be demonstrated. The four bands will span the

range from approximately 3 GHz to 12 GHz. In anticipation of this test, time will be spent trying

to understand the reduced efficiency and installing optical fiber for both polarizations.

In early January 2008 there will be a six-hour session on one source to evaluate possible

systematic differences between the two polarizations.

44 IVS 2007 Annual Report
HartRAO, NRF Hartebeesthoek Radio Astronomy Observatory (HartRAO)

Hartebeesthoek Radio Astronomy Observatory (HartRAO)

Ludwig Combrinck, Marisa Nickola

Abstract

HartRAO, the only fiducial geodetic site in Africa, participates in VLBI, GNSS, and SLR global

networks, among others. This report provides an overview of our geodetic VLBI activities and research

during 2007. Further developments regarding the proposed new fundamental space geodetic observatory

in the Karoo are presented.

1. Geodetic VLBI at HartRAO

Hartebeesthoek is located 65 kilometers northwest of Johannesburg within the World Heritage

Site known as the Cradle of Humankind, just inside the provincial boundary of Gauteng, South

Africa. The nearest town, Krugersdorp, is 32 km distant. The telescope is situated in an isolated

valley which affords protection from terrestrial interference. HartRAO uses a 26-metre equatorially

mounted Cassegrain radio telescope built by Blaw Knox in 1961. The telescope was part of the

NASA deep space tracking network until 1975 when the facility was converted to an astronomical

observatory. The telescope is co-located with an SLR station (MOBLAS-6) and an IGS GNSS

station (HRAO). HartRAO joined the EVN as an associate member during 2001. Geodetic VLBI

has been allocated 16% of the available telescope time. The allocation for geodetic VLBI was

increased from 52 24-hour experiments in 2006 to 58 in 2007.

Figure 1. The 26-m HartRAO radio telescope with

the 15-m XDM in the background. The XDM is

a testbed prototype for the Karoo Array Telescope

(KAT), which, in turn, will be used to test technology leading up to development of the Square Kilometer Array (SKA).

Figure 2. Andrew Masiteng and Richard Moralo

install the dichroic reflector, which permits simultaneous observing at 3.5 and 13 cm. The dichroic

has to be installed before and removed after every

geodetic VLBI experiment.

IVS 2007 Annual Report 45
Hartebeesthoek Radio Astronomy Observatory (HartRAO) HartRAO, NRF

2. Technical Parameters of the VLBI Telescope of HartRAO

The feed horns used for 13 cm and 3.5 cm are dual circularly polarized conical feeds. The RF

amplifiers are cryogenically cooled HEMTs. Tables 1 and 2 contain the technical parameters of

the HartRAO radio telescope and its receivers. The data acquisition system consists of a Mark

IV terminal and a Mark 5A recorder. The obsolete Mark IV and S2 tape recorders have been

removed from the control room. A 22 GHz receiver was installed on the 26-m telescope on the 1st

of February 2007 and was put to the test observing Jupiter. The surface upgrade proved its worth

when measurements of aperture efficiency showed the surface error near zenith to be 0.5 mm.

Table 1. Antenna parameters.

Parameter HartRAO-VLBI

Owner and operating agency HartRAO

Year of construction 1961

Radio telescope mount Offset equatorial

Receiving feed Cassegrain

Diameter of main reflector d 25.914 m

Focal length f 10.886 m

Focal ratio f/d 0.424

Surface error of reflector 0.5 mm

Wavelength limit < 1.3 cm

Pointing resolution 0.001◦

Pointing repeatability 0.004◦

Table 2. Receiver parameters with dichroic reflector (DR), used for simultaneous S-X VLBI, off or on.

Parameter X-band S-band

Tsys (DR off) (K) 60 44

Tsys (DR on) (K) 70 50

SSEFD (DR off) (Jy) 684 422

SSEFD (DR on) (Jy) 1330 1350

Point source sensitivity (DR off) (Jy/K) 11.4 9.6

Point source sensitivity (DR on) (Jy/K) 19 27

3 dB beamwidth (◦) 0.092 0.332

3. Staff Members Involved in VLBI

Antenna systems technician, Jacques Grobler, and electronics technician, Lerato Masongwa,

have joined the Geodetic VLBI Team as trainee operators during the second half of 2007. Table 3

lists the HartRAO station staff who are involved in geodetic VLBI. Jonathan Quick (VLBI friend)

has continued to provide technical support for the Field System as well as for hardware problems.

46 IVS 2007 Annual Report
HartRAO, NRF Hartebeesthoek Radio Astronomy Observatory (HartRAO)

Table 3. Staff supporting geodetic VLBI at HartRAO.

Name Function Programme

Ludwig Combrinck Programme Leader Geodesy

Jonathan Quick Hardware/Software Astronomy

Gert Agenbag Operator Geodesy - student

Joel Ondego Botai VLBI research Geodesy - student

Roelf Botha Operator Geodesy - student

Sarah Buchner Training Astronomy

Attie Combrink Operator Geodesy - post doctoral researcher

Jacques Grobler Trainee Operator Technical

Lerato Masongwa Trainee Operator Technical

Mojalefa Moeketsi Operator Geodesy - student

Marisa Nickola Logistics/Operations Geodesy

Pieter Stronkhorst Operator Technical

4. Current Status

During 2007 HartRAO participated in 58 experiments (table 4), which utilised the telescope

time allocated to geodetic VLBI to its fullest extent.

Table 4. Geodetic VLBI experiments HartRAO participated in during 2007.

Experiment Number of Sessions

R1 32

CRDS 7

OHIG 5

RDV 5

CRF 3

R&D 2

T2 2

CRFS 1

R4 1

Total 58

The 3.5-cm receiver was removed for maintenance on the 22nd of August 2007 and, after replacing the expander, microwave technician Ronnie Myataza ran several tests to verify the receiver’s

performance.

Ph.D. student Joel Ondego Botai has been researching the effects of the atmosphere on the

geodetic VLBI delay observable. To this end, Joel has been investigating limited area Numerical Weather Prediction (NWP) models and resolving high-frequency fluctuations of tropospheric

parameters that affect VLBI observations. This should hopefully add value to station-dependent

strategies of improving the accuracy of the geodetic VLBI observable.

IVS 2007 Annual Report 47
Hartebeesthoek Radio Astronomy Observatory (HartRAO) HartRAO, NRF

Figure 3. The 3.5-cm receiver being reassembled

after repairs.

Figure 4. Some of our geodetic VLBI staff—

from left to right, Jacques, Pieter, Marisa, Lerato,

Jonathan, and Roelf.

5. Future Plans

Planning towards the development of a new fundamental space geodetic observatory for South

Africa, the proposed International Institute for Space Geodesy and Earth Observation (IISGEO),

continued during 2007. The possibility of incorporating two KAT-type dishes into the future

equipment arsenal of IISGEO has been proposed by the Director of HartRAO, Prof. R. Booth. One

such prototype, the 15-m diameter eXperimental Development Model (XDM), has been constructed

at HartRAO, and it is expected that future models, such as smaller and lighter next-generation

KAT-7 12-m paraboloid and MeerKAT 12-m offset paraboloid dishes, will be able to meet higher

specifications of pointing and surface accuracy. This would enable operations for geodetic VLBI

purposes in the 2-18 GHz range, compatible with VLBI2010.

The Earth Observation research unit (Space Geodesy & Remote Sensing) was conceived during

2007 in collaboration with the University of Pretoria (UP). It is to be housed at UP and is eagerly

anticipated for the coming year. Lectures in Space Geodesy will be presented at undergraduate

level from 2008 and such courses extended to Honours level during 2009.

The Space Geodesy Programme is an integrated programme, combining VLBI, SLR, and GNSS,

and 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).

48 IVS 2007 Annual Report
University of Tasmania, Geoscience Australia Hobart, Mt. Pleasant Radio Astronomy Observatory

Hobart, Mt. Pleasant, Station Report for 2007

Brett Reid, John M. Dickey, Jim Lovell, Simon Ellingsen

Abstract

This is a brief report on the activities carried out at the Mt. Pleasant Radio Astronomy Observatory

at Hobart, Tasmania. During 2007, the observatory participated in 61 24-hour IVS VLBI observing

sessions, and funding commenced for the AuScope VLBI array which will see three new antennas

installed across Australia for geodesy.

1. Introduction

The Mt. Pleasant Observatory is located about 15 km north east of Hobart at longitude 147.5

degrees East and latitude 43 degrees South. Hobart is the capital city of Tasmania, the island

state of Australia located to the south of the mainland. The station is operated by the School

of Mathematics and Physics at the University of Tasmania. The station has a co-located GPS

receiver and a site which is used for absolute gravity measurements.

2. Brief Description of VLBI Facilities

The antenna is a 26 m prime focus instrument with an X-Y mount. The focus cabin has a

feed translator with provision for four different receiver packages, which enables rapid changeover

between geodetic and astronomical requirements. Standard receiver packages provide for operation

at L band and S, C, X, and K bands. There is also the dual frequency S/X geodetic receiver. All

of these receivers are cryogenically cooled. The antenna has a maximum slew rate of 40 degrees

per minute about each axis. The station is equipped with a Mark IV electronics rack and a Mark

5 VLBI recording system. There is another disk based recording system used by other Australian

VLBI antennas.

3. Staff

Staff at the observatory consisted of academics, Prof. John Dickey (director), Dr. Simon

Ellingsen, Dr. Melanie Johnston Hollitt, and Prof. Peter McCulloch, who has had a large input into the receiver design and implementation. Dr. Aidan Hotan and Dr. Jamie Stevens are

research fellows and have had input into the Linux systems at the observatory. 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, and we had a half time mechanical technical officer,

Mr. Geoff Tonta. For operation of the observatory during geodetic observations we rely heavily on

support from astronomy Ph. D. and post-graduate students. In 2007 Dr. Jim Lovell was appointed

as Project Scientist for the AuScope VLBI project (see Future Plans below).

4. Geodetic VLBI Observations

Hobart participated in 61 geodetic VLBI experiments during 2007. These were divided between

the APSG, CRDS, CRF, OHIG, R1, R4, R&D, and T2 programs. All experiments were recorded

IVS 2007 Annual Report 49
Hobart, Mt. Pleasant Radio Astronomy Observatory University of Tasmania, Geoscience Australia

Figure 1. The Mt. Pleasant 26m antenna.

using Mark 5A. In 2007, Hobart increased its support of IVS by commiting to participate in 60

24-hour experiments, an increase of 36% above those performed in 2006. The ARC LIEF (Large

Infrastructure and Equipment Funding) funded 10 Gb/s fiber optic link between the Mt. Pleasant

VLBI site and the university campus was completed during 2007. Links out of Tasmania are

currently limited to 2 × 155 Mbps, which will be upgraded to Gbps rates by the end of 2008.

In 2007 the University completed work on a visitors center and museum at the observatory,

funded from the estate of Grote Reber, the world’s first radio astronomer. The museum includes

a display on the contribution the Mt. Pleasant 26 m antenna makes to geodesy through the IVS.

5. Future Plans

2008 will see the construction of a new 12 m antenna at Mt. Pleasant for geodesy as part of the

AuScope VLBI project. AuScope is part of the Australian government’s National Collaborative

Research Infrastructure Strategy (NCRIS). It encompasses NCRIS Capability 5.13: “Structure

and Evolution of the Australian Continent”. An important part of this is the acquisition of three

new radio telescopes and a data processing facility for geodesy. Construction of the other two

telescopes will take place in 2009 in Western Australia and Northern Territory. It is anticipated

that these antennas will be dedicated to IVS observations for approximately 50% of the time. This

five year project, for which funding started in 2007, will vastly improve the capabilities of the

IVS in the southern hemisphere. The array will be operated for AuScope by the University of

Tasmania with data correlation supported by Curtin University of Technology. The construction

and operation of the array is being managed for AuScope by the University of Tasmania.

50 IVS 2007 Annual Report
Kashima Space Research Center, NICT Kashima 34-m Radio Telescope

Kashima 34-m Radio Telescope

Hiroshi Takiguchi, Eiji Kawai, Hiromitsu Kuboki, Tetsuro Kondo

Abstract

The Kashima 34-m radio telescope is continuously operated and maintained by the National Institute of Information and Communications Technology (NICT) as a facility of the Kashima Space

Reserch Center (KSRC) in Japan. This brief report summarizes the status of this telescope, the staff

and activities during 2007.

1. General Information

The Kashima 34-m radio telescope (Figure 1 left) was constructed by NICT (formerly Communications Research Laboratory) as a main station of the “Western Pacific VLBI Network Project”

in 1988. After that project ended, the telescope has been used not only for geodetic purposes

but also for astronomy and other purposes [1] [4]. The station is located about 100 km East of

Tokyo, Japan and co-located with the 11-m radio telescope and the International GNSS Service

station (KSMV) (Figure 1 right). During 19 years of operation, this telescope has been kept in a

fairly good condition. This station is maintained by the Space-Time Applications Project of the

Space-Time Standards Group of KSRC, NICT.

The Kashima 34-m radio telescope.

34-m radio

Kashima Station

11-m radio

telescope

telescope

GEONET Station

IGS Station

The layout map of Kashima station.

Figure 1. The Kashima Station.

2. Component Description

The Kashima 34-m radio telescope can observe L, C, K, Ka, Q, S, and X bands. The main

specifications of the telescope and receivers are summarized in Table 1 and Table 2.

IVS 2007 Annual Report 51
Kashima 34-m Radio Telescope Kashima Space Research Center, NICT

Table 1. Main specifications of the 34-m radio telescope.

Main reflector aperture 34.073 m

Latitude N 35◦ 57’ 21.78”

Longitude E 140◦ 39’ 36.32”

Height of AZ/EL intersection above sea level 43.4 m

Height of azimuth rail above sea level 26.6 m

Antenna design Modified Cassegrain

Mount type AZ-EL mount

Drive range azimuth North ±270◦

Drive range elevation 7◦-90◦

Maximum speed azimuth 0.8

◦/sec

Maximum speed elevation 0.64◦/sec

Maximum operation wind speed 13 m/s

Panel surface accuracy r.m.s. 0.17 mm

Table 2. The receiver specification of the 34-m radio telescope.

Band frequency (MHz) Trx (K) Tsys (K) Efficiency SEFD (Jy) Polarization

L 1350-1750 18 45 0.68 200 L/R

S 2193-2350 19 72 0.65 340 L/R

C 4600-5100 100 127 0.70 550 L(R)

X-n 8180-9080∗ 41 52 0.68 230 L/R

X-wL 8180-9080# 41 53 0.68 290 L/R

X-wH 7860-8360# - 50 0.68 270 L/R

K 22000-24000⋆ 105 141 0.5 850 L(R)

Ka 31700-33700 85 150 0.4 1100 R(L)

Q 42300-44900 180 350 0.3 3500 L(R)

∗ : 8GHz LNA narrow band use. # : 8GHz LNA wide band use.

⋆ : changed due to the repair on 19 January, 2007.

The original frequency coverage of the X-band was from 7860 MHz to 8600 MHz. In order to

respond to IVS observation, we expanded the frequency range of the X-band receiver up to 9080

MHz [2]. For S-band, we installed the new high-temperature superconductor (HTS) band-pass

filter to mitigate the radio frequency interference (RFI) signal due to a third-generation mobile

phone system (IMT-2000) [3].

3. Staff

The engineering and technical staff of the Kashima 34-m radio telescope are listed in Table 3.

Hiromitsu Kuboki left NICT and Kazuhiro Takefuji joined in December 2007.

52 IVS 2007 Annual Report
Kashima Space Research Center, NICT Kashima 34-m Radio Telescope

Table 3. The engineering and technical staffs of the Kashima 34-m radio telescope.

Name Main Responsibilities

Eiji Kawai responsible for operations and maintenance

Mamoru Sekido software and reference signals

Hiromitsu Kuboki mechanical and RF related parts

Kazuhiro Takefuji mechanical and RF related parts

Yasuhiro Koyama international e-VLBI

Tetsuro Kondo software correlator developments and e-VLBI

4. Current Status and Activities

The 34-m radio telescope contributed to various experiments (such as geodesy, radio-astronomy,

space navigation, time transfer). Statistical charts of the telescope operation time according to

purpose including maintenance is shown in Figure 2. The total operation time of 2007 was 2319

hours, which is a significant increase compared with the previous year. The main reason for this

is that there was no major telescope trouble [4].

Spacecraft Orbit

Pulsar Timing

Maintenance etc.

Internal

International

e-VLBI

Astronomical Obs.

Geodetic Obs.

45%

21%

14%

10%

6%

3%

1%

Geodetic Obs.

Total operation time : 2319 hours

Statistical charts of the telescope

operation time according to purpose.

0

500

1000

1500

2000

2500

other

e-VLBI

Spacecraft Orbit

Pulsar Timing

International

Internal

Astronomical Obs.

Maintenance etc.

2005 2006 2007

hours

Geodetic Obs.

Geodetic Obs.

Telescope operation time within the last three years.

Figure 2. Statistical charts of the telescope operation time.

The yearly maintenance was carried out from the beginning of August until the end of September. Repair work was done on the backing structure of the telescope as well as on the access ladder

of the main reflector and the sub-reflector [4].

Figure 3 shows the block diagram of the current S/X-band receiver system [4].

5. Future Plans

The Kashima 34-m radio telescope is a main telescope of our project and already a lot of

observations such as “experiment for the development of a 1.6m antenna system”, “ultra-rapid UT1

experiment with e-VLBI”, and “VLBI experiment for Time Transfer” have been scheduled. Also

we are planning the yearly maintenance to keep up the telescope’s good condition. Additionally,

IVS 2007 Annual Report 53
Kashima 34-m Radio Telescope Kashima Space Research Center, NICT

P-cal

N.D. N.D.

H

H

H

HN.D. P-cal

H

8080MHz

PLO

2020MHz

PLO 7760MHz

T= 20kT= 50k

Cold Load

Hot Load Hot Load

Cold Load

2/8GHz Feed Horn8GHz LHCP

LPF

(0-12.3GHz)

LPF

(0-12.3GHz)

BPF

(8180-9080MHz)

(8180-9080MHz)

(7860-8360MHz)

2GHz

IF out

8GHz

X-n

IF out#1

8GHz

X-wH

IF out#2

8GHz

X-wL

IF out#3

Kashima 34m Antenna 2007_12 -

S/X Frontend (current)

Dewar

HTS-BPF

(2193-2473MHz)

Dewar

Sky Freq

(2193-2350MHz)

8GHz RHCP

2GHz RHCP 2GHz LHCP

LPF

(0-3.3GHz)

BPF

(2150-2350MHz)

H

Figure 3. The block diagram of the Kashima 34-m radio telescope S/X receiver after December 2007.

we are planning to restore the following items to improve the telescope’s condition:

• Brake malfunction (occurs rarely)

• Creak at the AZ wheel rotation part

• Rust of the backing structure

• Deterioration of the AZ base plate and rail

• Stain of the main reflector

References

[1] Kawai, E., H. Kuboki, Kashima 34-m Radio Telescope, In: International VLBI Service for Geodesy

and Astrometry 2006 Annual Report, NASA/TP–2007-214151, D. Behrend and K. D. Baver (eds.),

51–54, 2007.

[2] Kawai, E., H. Kuboki, Y. Koyama, T. Kondo, On the expansion of the frequency coverage of an X-band

of Kashima 34-m antenna, IVS NICT TDC News, 26, 23-25, 2005.

[3] Kawai, E., J. Nakajima, H. Takeuchi, H. Kuboki, T. Kondo, M. Suzuki, K. Saito, RFI mitigation at a

2GHz band by using a wide-band high-temperature superconductor filter, J. Geod. Soc. Japan, 2007

(in press).

[4] Space-Time Standards Group, NGNC, NICT, Kashima 34-m Radio Telescope 2007 Annual Report,

2008 (in Japanese).

54 IVS 2007 Annual Report
Kashima Space Research Center, NICT Kashima and Koganei 11-m VLBI Stations

Kashima and Koganei 11-m VLBI Stations

Yasuhiro Koyama

Abstract

Two 11-m VLBI stations at Kashima and Koganei used to be a part of the Key Stone Project VLBI

Network. The network consisted of four VLBI stations at Kashima, Koganei, Miura, and Tateyama.

Since Miura and Tateyama stations have been transported to Tomakomai and Gifu, Kashima and Koganei 11-m stations are remaining as IVS Network Stations. After the regular VLBI sessions with the

Key Stone Project VLBI Network terminated in 2001, these stations are mainly used for the purposes

of technical developments and miscellaneous observations. In 2007, a series of geodetic VLBI experiments was performed between Kashima and Koganei 11-m VLBI stations to evaluate the capability of

the VLBI technique for precise time transfer between Time and Frequency laboratories to construct

Coordinated Universal Time. In addition, efforts to determine the precise orbit of spacecraft were

continued by using Hayabusa and Geotail spacecraft. Another series of experiments was also carried

out for developments of e-VLBI by using the high speed network connection between the sites.

1. Introduction

The Key Stone Project (KSP) was a research and development project of the National Institute of Information and Communications Technology (NICT, formerly Communications Research

Laboratory) [1]. Four space geodetic sites around Tokyo were established with VLBI, SLR, and

GPS observation facilities at each site. The locations of the four sites were chosen to surround

Tokyo Metropolitan Area to regularly monitor the unusual deformation in the area (Figure 1).

Koganei Kashima

Miura

Tateyama

Tomakomai

Gifu

145 E 135 E 140 E

35 N

40 N

Figure 1. Geographic locations of four KSP VLBI stations and two stations at Tomakomai and Gifu.

Therefore, the primary objective of the KSP VLBI system was to determine precise site positions of the VLBI stations as frequently and fast as possible. To realize this objective, various

new technical advancements were attempted and achieved. By automating the entire process from

the observations to the data analysis and by developing the real-time VLBI system using the high

speed digital communication links, unattended continuous VLBI operations were made possible.

Daily continuous VLBI observations without human operations were actually demonstrated and

IVS 2007 Annual Report 55
Kashima and Koganei 11-m VLBI Stations Kashima Space Research Center, NICT

the results of data analysis were made available to the public users immediately after each VLBI

session. Improvements in the measurement accuracies were also accomplished by utilizing fast

slewing antennas and by developing higher data rate VLBI systems operating at 256 Mbps.

The 11-m antennas and other VLBI facilities at Miura and Tateyama stations have been transported to Tomakomai Experimental Forest of the Hokkaido University and to the campus of Gifu

University, respectively. As a consequence, two 11-m stations at Kashima and Koganei (Figure 2)

are remaining as IVS Network Stations. After the regular VLBI sessions with the Key Stone

Project VLBI Network terminated in 2001, 11-m VLBI stations at Kashima and Koganei are

mainly used for the purposes of technical developments and miscellaneous observations.

Figure 2. 11-m VLBI antennas at Kashima (left) and Koganei (right).

2. Activities in 2007

In 2007, we started to perform special purpose geodetic VLBI experiments between Kashima

(11-m or 34-m) and Koganei VLBI stations to evaluate the capability of VLBI for precise time

transfer. Currently, the International Bureau of Weights and Measures (BIPM) is maintaining and

evaluating Coordinated Universal Time (UTC) by assembling many time and frequency standards

operated at Time and Frequency Laboratories around the world. The common view GPS time

transfer and bi-directional satellite time transfer are mainly used to compare timing signals of

time and frequency standard systems. It is necessary to compare the clocks over a long distance

and the current accuracy of the time comparison is typically a few hundred picoseconds by using

the bi-directional satellite time transfer technique. On the other hand, the clock offsets between

two stations is estimated from usual geodetic VLBI experiments and its typical uncertainty of

about a few tens of picoseconds. In addition, it is anticipated to achieve 3 to 4 picoseconds of

uncertainty for time delay measurements by using multi-frequency wide band phase delay measurements under the VLBI2010 discussions. At Koganei headquarters of NICT, a set of Cesium

Atomic Clocks, Hydrogen Maser Frequency Standard systems, and primary frequency standard

56 IVS 2007 Annual Report
Kashima Space Research Center, NICT Kashima and Koganei 11-m VLBI Stations

systems are operated to contribute to the UTC. In addition, optical frequency standard systems

are being developed by using Calcium ion and optical lattice clock techniques. It is expected to

achieve frequency stability of down to 10−16 of Allen Standard Deviation. If such a highly stable

optical frequency standard system is realized, it is necessary to perform precise time transfer with

the other time and frequency laboratories and the geodetic VLBI technique is expected to improve

the current time transfer limitation. We are currently developing a very small wideband antenna

system of the aperture of 1.6m in diameter and we would like to demonstrate the capability of the

geodetic VLBI technique for precise time transfer. At first, two 24-hours sessions were performed

on January 11th and on 22nd. Then a three-day continuous session was performed from February

28th, and a one-week continuous session was performed starting on June 15th. At both 11-m

stations, continuous GPS observations were also performed as IGS sites, and these data are used

to compare with the results from VLBI observations. The evaluation of the obtained results is still

under investigation, but the initial analysis suggested the capability of VLBI methods for precise

time transfer of the level of 16 picoseconds.

For technical developments, the baseline between Kashima and Koganei is also used as a test

bed for real-time VLBI observations based on the Internet Protocol (IP). The two stations used

to be connected by high speed Asynchronous Transfer Mode (ATM) network in collaboration

with the NTT Laboratories until July 2003. From April 2004, NICT started to operate a high

speed research test-bed network called JGNII and both the Kashima and Koganei stations are

connected to the JGNII backbone with OC-192 (10 Gbps) connection. JGNII is a follow-on project

of the JGN (Japan Gigabit Network) which was operated by the Telecommunications Advancement

Organization of Japan (TAO) for 5 years from 1999. When TAO was merged with Communications

Research Laboratory to establish NICT as a new institute, JGNII succeeded the JGN project.

Whereas the JGN project was operated based on the ATM architecture, the new JGNII network

mainly uses IP. One GbE (Gigabit Ethernet) interface is installed at Koganei station and two

GbE interfaces are connected at Kashima station. This environment provides us with an ideal

opportunity for e-VLBI research and developments.

Efforts to determine precise orbit of spacecrafts by means of differential VLBI observations

were also continued from previous years. The S-band telemetry signal from the Geotail and

Hayabusa spacecraft were used to demonstrate precise orbit determination by means of differential

VLBI observations. These efforts were initiated in 2003 with the requirements for precise orbit

determination of spacecraft Nozomi and Hayabusa. Such efforts are still continuing hoping to

improve the technique for future space missions.

Apart from the VLBI sessions, the Space Environment Group of NICT started to use the 11-m

antenna at Koganei to download data from the STEREO spacecraft. Two STEREO spacecraft

were launched by NASA in October 2006 to investigate solar terrestrial environment and 3D image

of the Sun and solar storms. The Koganei 11-m antenna is therefore operated everyday even if

there is no VLBI sessions to perform.

3. Staff Members

The 11-m antenna stations at Kashima and Koganei are operated and maintained by the

Space-Time Standards Group at Kashima Space Research Center, NICT. The staff members of

the group are listed in Table 1. The operations and maintenance of the 11-m VLBI station at

Koganei is also greatly supported by Space-Time Standards Group, Space Environment Group

IVS 2007 Annual Report 57
Kashima and Koganei 11-m VLBI Stations Kashima Space Research Center, NICT

and Space Communications Group at Koganei Headquarters of NICT. We are especially thankful

to Jun Amagai and Tadahiro Gotoh for their support.

Table 1. Staff members of Space-Time Standards Group, KSRC, NICT

Name Main Responsibilities

Yasuhiro KOYAMA Administration

Eiji KAWAI Antenna system

Hiromitsu KUBOKI Antenna System

Mamoru SEKIDO Field System, Calibration and Frequency Standard Systems

Ryuichi ICHIKAWA Meteorological Sensors, IGS Receivers

Masanori TSUTSUMI System Engineer

4. Future Plans

In 2008, we plan to continue the precise time transfer VLBI experiments, e-VLBI developments,

and differential VLBI observations to the spacecraft for precise orbit determination. In addition

to the VLBI observations and developments, the data downlink from the two STEREO spacecraft

will be continued.

References

[1] Special issue for the Key Stone Project, J. Commun. Res. Lab., Vol. 46, No. 1, March 1999

[2] Koyama, Y., T. Kondo, H. Osaki, K. Takashima, K. Sorai, H. Takaba, and K. Fujisawa, IVS CRL

TDC News, No. 23, Nov. 2003, pp. 26-30

[3] Koyama, Y., T. Kondo, M. Kimura, and H. Takeuchi, IVS NICT TDC News, No. 26, Sep. 2005, pp.

9-12

58 IVS 2007 Annual Report
USNO and NASA GSFC Kokee Park Geophysical Observatory

Kokee Park Geophysical Observatory

Kelly Kim

Abstract

This report summarizes the technical parameters and the staff of the VLBI system at Kokee Park

on the Island of Kauai.

1. KPGO

Kokee Park Geophysical Observatory (KPGO) is located in the Kokee State Park on the island

of Kauai in Hawaii at an elevation of 1100 meters near the Waimea Canyon, often referred to as

the Grand Canyon of the Pacific.

Figure 1. KPGO 20m antenna and operations building.

2. Technical Parameters of the VLBI System at KPGO

The receiver is of NRAO (Green Bank) design (dual polarization feed using cooled 15 K HEMT

amplifiers). The DAR rack and tape drive were supplied through Green Bank. The antenna is

of the same design and manufacture as those used at Green Bank and Ny- ̊Alesund. We presently

employ a Mark 5A recorder for all of our data recording.

The technical parameters of the radio telescope are summarized in Table 2.

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 system. The Sigma Tau performance is also monitored via the IGS Network.

IVS 2007 Annual Report 59
Kokee Park Geophysical Observatory USNO and NASA GSFC

Table 1. Location and Addresses of Kokee Park Geophysical Observatory.

Longitude 159.665◦ W

Latitude 22.126◦ N

Kokee Park Geophysical Observatory

P.O. Box 538 Waimea, Hawaii 96796

USA

Table 2. 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 − 8.9 GHz

Tsys 40 K

SSEFD(CASA) 900 Jy

G/T 45.05 dB/K

η 0.406

S-band

(reference ν = 2.3GHz, λ = 0.1304m)

2.2 − 2.4GHz

Tsys 40 K

SSEFD(CASA) 665 Jy

G/T 35.15 dB/K

η 0.539

VLBI terminal type VLBA/VLBA4-Mark 5

Field System version 9.7.6

3. Staff of the VLBI System at KPGO

The staff at Kokee Park during calendar year 2007 consisted of five people who are employed

by Honeywell International under contract to NASA for the operations and maintenance of the

60 IVS 2007 Annual Report
USNO and NASA GSFC Kokee Park Geophysical Observatory

Observatory. VLBI operations and maintenance was conducted by Matt Harms, Chris Coughlin and Kelly Kim. Ben Domingo does antenna maintenance with Amorita Apilado providing

administrative, logistical and numerous other support functions.

Figure 2. KPGO Maintenance Day.

4. Status of KPGO

Kokee Park has participated in many VLBI experiments since 1984. We started observing with

GAPE, continued with NEOS and CORE, and are now in IVS R4 and R1. We also participate in

the RDV experiments.

We averaged 1.5 experiments per week during calendar year 2000 and increased to an average

of 2 experiments of 24 hours each week, with daily Intensive experiments during year 2002 and

into 2007.

Kokee Park also hosts other systems, including a 7m PEACESAT command and receive antenna, a DORIS beacon, and a Turbo-Rogue GPS receiver. Kokee Park is an IGS station.

Canadian S2 support ended late in 2006 due to Canadian government budget cuts leading to

the demise of their program. Also in 2006, PRARE support ended when the equipment became

no longer supportable due to lack of spares. We will miss both of these projects and wish those

we’ve met working on these programs the very best in the future.

IVS 2007 Annual Report 61
Kokee Park Geophysical Observatory USNO and NASA GSFC

Figure 3. PEACESAT 7m Antenna.

In 2006, use of the tape recorder ceased, and we now use the Mark 5 for all VLBI supports

with the exception of the Australian S2 supports, which run on their own system using VHS tapes.

Late in 2006, we had problems with our primary (SigTau) maser, and we have been using our

backup (NASA NR-1) maser as our primary while awaiting parts to be procured for the SigTau

repair.

In mid-2007, we filled the staff vacancy to bring our manpower level back to 100%.

Representatives from the Carnegie Institute removed a seismic station that was installed a few

years earlier due to the end of the need to gather data at our location.

In October of 2007, Japanese interests, along with representatives from NASA, USNO and

the State Department, held a meeting at KPGO to explore the possible installation of a project

called QZSS. In December, they announced that the first phase of the joint project would begin

construction in the spring of 2008.

5. Outlook

We are closer to providing real time e-VLBI, and testing for system performance and data

transmission evaluation is being discussed for late 2008. Steps have been taken to secure a wide

band pipe needed for this support.

The QZSS project will begin installation of its equipment in 2008 and is looking at an early

2010 timeframe for reaching full operational capability.

We are supposed to participate in the CONT08 series of experiments later this year.

NASA plans to upgrade aging building infrastructure and will be investigating options to bring

about the much needed repairs.

62 IVS 2007 Annual Report
Agenzia Spaziale Italiana Matera CGS VLBI Station

Matera CGS VLBI Station

Giuseppe Bianco, Giuseppe Colucci, Francesco Schiavone

Abstract

This report describes the status of the Matera VLBI station. Also an overview of the station, some

technical characteristics of the system and staff addresses are given.

1. General

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

Figure 1. The Matera “Centro di Geodesia Spaziale” (CGS).

in 1983 when a Satellite Laser Ranging SAO-1 System was installed at CGS. Fully integrated in

the worldwide network, SAO-1 was in continuous operation from 1983 up to 2000, providing high

IVS 2007 Annual Report 63
Matera CGS VLBI Station Agenzia Spaziale Italiana

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, has

been installed in 2002 and replaced the old SLR system. CGS hosted also 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 radiotelescope. Since then, Matera performed 761 sessions up to December 2007.

In 1991 we started GPS activities, participating in the GIG 91 experiment installing in Matera

a permanent GPS Rogue receiver. In 1994 six TurboRogue SNR 8100 receivers were purchased in

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 WWW server GeoDAF (http://geodaf.mt.asi.it).

Thanks to the co-location of all precise positioning space based techniques (VLBI, SLR, LLR

and GPS), 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 also to remote sensing activities for present and future missions (ERS1, ERS-2, X-SAR/SIR-C, SRTM, ENVISAT, COSMO-SkyMed).

2. Technical/Scientific Overview

The Matera VLBI antenna is a 20-meter dish with a Cassegrain configuration and AZ-EL

mount. The AZ axis has ±270 degrees of available motion. The slewing velocity is 2 deg/sec for

both AZ/EL axis.

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 H-maser standard) and three independent clock chains. The EFOS-8 H-maser from

Oscilloquartz is used as a frequency source for VLBI.

The control computer is a SWT Pentium/233 PC running Linux and FS version 9.9.2.

Table 1. Matera VLBI Antenna Technical Specifications.

Input frequencies S/X 2210−2450 MHz / 8180−8980 MHz

Noise temperature at dewar flange S/X <20 K

IF output frequencies S/X 190−430 MHz / 100−900 MHz

IF Output Power (300 K at inp. flange) S/X 0.0 dBm to +8.0 dBm

Gain compression S/X <1 dB at +8 dBm output level

Image rejection S/X >45 dB within the IF passband

Inter modulation products S/X At least 30 dB below each of 2 carriers

at an IF output level of 0 dBm per carrier

Tsys S/X 55/65 K

SEFD S/X 800/900 Jy

64 IVS 2007 Annual Report
Agenzia Spaziale Italiana Matera CGS VLBI Station

3. Staff

The list of the VLBI staff members of Matera VLBI station is provided in Table 2.

Table 2. Matera VLBI staff members.

Name Agency Activity E-Mail

Dr. Giuseppe Bianco ASI VLBI Manager giuseppe.bianco@asi.it

Francesco Schiavone Telespazio Operations Manager francesco.schiavone@telespazio.com

Giuseppe Colucci Telespazio VLBI contact giuseppe.colucci@telespazio.com

4. Status

In 2007, 52 sessions were acquired. All sessions were acquired using Mark 5 only. Fig. 2 shows

the total Acquisitions Summary per year, starting in 1990.

In 2004, in order to fix all the rail problems, a complete rail replacement was planned. In

2005, due to financial difficulties, it was instead decided to repair the concrete pedestal under the

existing rail only. From then on, no rail movements have been noted [1]-[3].

Figure 2. Acquisitions per year.

IVS 2007 Annual Report 65
Matera CGS VLBI Station Agenzia Spaziale Italiana

5. Outlook

The rail works are now on low priority because during last year no significant deterioration has

been noted.

The main goal is to replace at least 1 of the 4 azimuth wheels because of cracks on the surface.

This important work should be done in May-June 2008.

Another goal is to replace the Antenna Control Unit and both Azimuth and Elevation encoders,

because it is not possible to find spare parts for these components anymore.

References

[1] M. Mannarella “Relazione sulle misure effettuate sulla rotaia dell’antenna VLBI“, Telespazio doc. OTSPA-SM REL 180010 1140 0222, 21/01/2004.

[2] M. Mannarella “Misure sugli spostamenti indotti sulle piastre e sulla rotaia dell’antenna VLBI“,

Telespazio doc. OT-SPA-SM REL 180010 1320 0661, 06/04/2005.

[3] M. Mannarella “Relazione sull’esito dei lavori di ripristino delle parti ammalorate della fondazione

dell’antenna VLBI“, Telespazio Doc. OT-SPA-SM REL 180010 1320 0732, 27/06/2005.

66 IVS 2007 Annual Report
Istituto di Radioastronomia, Medicina Medicina Network Station

The Medicina Station Status Report

Alessandro Orfei, Andrea Orlati, Giuseppe Maccaferri, Franco Mantovani

Abstract

General information about the Medicina Radio Astronomy Station, the 32 m antenna status, and

the staff in charge of VLBI observations are provided. In 2007 the data from geodetic VLBI observations

were acquired using the Mark 5A recording system with good results. Updates of the hardware have

been 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 about 33 km East of Bologna. The

Consiglio Nazionale delle Ricerche was the funding agency of the Istituto di Radioastronomia till

the end of 2004. Since January 1st, 2005 the funding agency is the Istituto Nazionale di Astrofisica

(INAF).

The antenna, 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, which is part of the

IGS network, is installed in the vicinity. Another GPS system is installed near the VLBI telescope

(MSEL) and is part of the EUREF network.

2. Antenna Description

The Medicina antenna has Cassegrain optics, consisting of a primary mirror of 32 m in diameter,

and a secondary mirror, called subreflector, of convex shape and about 3 m in diameter. The

subreflector, mounted on a quadrupode, is placed opposite the primary mirror, and focuses the

radio waves at its centre, where the receiver system is located. For some observing frequencies, a

simplified optical system is enough. The subreflector is therefore shifted from its normal position,

and the receiving system is placed at the primary focus: this is the case of the S-X observations.

The antenna can operate in the range between 327 MHz and 22 GHz.

The receivers are cooled with cryogenic techniques to improve the system sensitivity. The

antenna is flexible in changing the operative receiver: only a few minutes are needed to change the

observing frequency. A recent picture of the antenna is shown in Figure 1.

3. The Staff

Many scientists and technicians are taking care of the observations. However, there is a limited

number of people that is dedicated to maintain and improve the reliability of the antenna during

the observations: Alessandro Orfei is the Chief Engineer, expert in micro-wave receivers; Giuseppe

Maccaferri is the Technician in charge of the telescope’s backend; Andrea Orlati is the Software

Engineer who takes care of the observing schedules and regularly implements SKED&DRUDG and

the Field System.

IVS 2007 Annual Report 67
Medicina Network Station Istituto di Radioastronomia, Medicina

Figure 1. View of the Medicina 32 m dish taken during geodetic VLBI observations. Note that the subreflector is shifted to allow the use of the S/X receiver located in the primary focus of the radio telescope.

4. Current Status and Activities

During 2007 the Field System version 9.9.0 was running routinely. The Mark 5A recording

system worked fine; it was upgraded to support 1 Gbit activity via installation of the suggested

operating system (Sarge). At the end of the year, we acquired the new MarkB system. All

observations are made onto hard disk. New disk frames with a storage capacity of 20 TB will

be available for geodetic observations. The 18-26 GHz multifeed system is in the final stage of

measurement. First antenna tests are foreseen for the beginning of 2008. The central feed will be

the new K band receiver for VLBI: great improvements with respect to the current receiver are

expected. The development of the new observing system and control software of the 32 m antenna

proceeds. Two PhD students have joined the team. INAF plans to fund the replacement of the

elevation wheel. Problems are still present in the ground unit, specifically in the lock of VC 13 and

at the cryogenic circuit of the S/X receiver. Final resolution of these problems will be attempted

in 2008.

4.1. Optic Fiber Link

Medicina participated routinely in e-VLBI tests and e-VLBI experiments.

5. Geodetic VLBI Observations

During 2007, the Medicina 32 m dish took part in 25 geodetic VLBI sessions, namely 2 IVS-T2,

13 IVS-R4, 2 IVS-R1, 4 EUROPE, and 4 R&D experiments.

68 IVS 2007 Annual Report
Mizusawa VERA Observatory National Astronomical Observatory of Japan

VERA Geodetic Activities

Takaaki Jike, Seiji Manabe, Yoshiaki Tamura, Makoto Shizugami, VERA group

Abstract

This report describes the status of the VERA network in terms of geodetic VLBI. The main contents

are information about the technical parameters of the VERA observation system and a summary of

geodetic VLBI activities during 2007.

1. General Description

VERA is a Japanese domestic VLBI network operated by Mizusawa VERA Observatory, NAOJ.

Four antennas, Mizusawa, Iriki, Ogasawara, and Ishigakijima, form this array. Each station is

equipped with a 20m radio telescope and a VLBI data aquisition system. Observing frequency

bands of VERA are S and X, K (22 GHz) and Q (43 GHz). The Iriki antenna is shown in Figure

1. The VERA array is controlled from the Array Operation Center at Mizusawa via Internet.

The primary scientific goal of VERA is to reveal the structure and dynamics of our Galaxy by

determining 3-D force field and mass distribution. Galactic maser sources are used as dynamical

probes, 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. VERA standard astrometric observations started in 2003. Distances of several maser

sources were measured in 2007.

Geodetic observations with VERA started in late 2002 and have been done routinely since late

2004. Monitoring of positions and movements of VERA sites by geodetic observations contributes

to keeping the accuracy of the VERA astrometric measurements. Geodetic observations are made

in S/X- and K-bands.

General information about the VERA stations is summarized in Table 1 and the geographic

locations are shown in Figure 2. Lengths of baselines range from 1000 km to 2272 km. Ogasawara

and Ishigakijima are small islands in the open sea and their climate is subtropical.

Table 1. General information

Sponsoring agency Mizusawa VERA Observatory,

National Astronomical Observatory of Japan

Contributing type Network observing station

Location

Mizusawa 141◦ 07’ 57”.2E, 39◦ 08’ 00”.7N, 75.7m(a.s.l.)

Iriki 130◦ 26’ 23”.6E, 31◦ 44’ 52”.4N, 541.6m(a.s.l.)

Ogasawara 142◦ 12’ 59”.8E, 27◦ 05’ 30”.5N, 223.0m(a.s.l.)

Ishigakijima 124◦ 10’ 15”.6E, 24◦ 24’ 43”.8N, 38.5m(a.s.l.)

2. Technical Parameters

Parameters of the antennas and the front- and back-end systems are summarized in Tables 2

and 3, respectively. The 1 Gbps recorder named DIR2000 is shown in Figure 3.

IVS 2007 Annual Report 69
National Astronomical Observatory of Japan Mizusawa VERA Observatory

Figure 1. VERA Iriki antenna (foreground) Figure 2. Location of VERA stations

Table 2. Antenna parameters

Diameter 20m

Mount Azimuth–Elevation

Surface accuracy 0.2mm(rms)

Pointing accuracy <12”(rms)

S X K

HPBW 1550” 400” 150”

Aperture efficiency 0.25 0.4 0.47

Slew Azimuth Elevation

range -90◦–450◦ 5

◦–85◦

speed 2

◦

.1/sec 2

◦

.1/sec2

acceleration 2

◦

.1/sec2 2

◦

.1/sec2 Figure 3. DIR2000: 1 Gbps recorder used in VERA

operations.

3. Activities of Geodetic VLBI Observation

Two observation modes are used for geodetic observations. One is the VERA internal geodetic

observation. The observing frequency bands are S/X and K and the recording rate is 1 Gbps. The

other is the joint observation with the Geographic Survey Institute (GSI) by Mizusawa’s participation in GSI’s domestic observation sessions called JADE. The purpose of the JADE participation is

to obtain VERA’s coordinates in the terrestrial reference frame realized by the IVS. Its frequency

band is S/X and the recording rate is 128 Mbps. A K5-VSSP data aquisition terminal is used.

During 2007, VERA internal geodetic observations were carried out 20 times. These observations are divided into 17 K-band sessions and 3 S/X-band sessions. We tried changing the geodetic

observation frequency from S/X to K. There seems to be no significant systematic difference in

the estimated coordinates between S/X and K-bands. As a result, all sessions after October used

K-band.

1 Gbps recording mode according to JADE schedule started at all VERA stations. The same

observations raw data sent from Tsukuba 32m antenna via G-bit optical fiber network was recorded

70 IVS 2007 Annual Report
Mizusawa VERA Observatory National Astronomical Observatory of Japan

Table 3. Front-end and back-end parameters

front-end

Frequency Frequency Receiver Polarization Receiver Feed

band range(GHz) temperature type

S 2.18–2.36 100K RHC HEMT Helical array

X 8.18–8.60 100K RHC HEMT Helical array

K 21.5–24.5 39±8K LHC HEMT(cooled) Horn

back-end

Type channels BW/channel Filter Recorder Deployed station

VERA 16 16MHz Digital DIR2000 4 VERA

K5-VSSP 16 4MHz VC HDD Mizusawa

by using 1 Gbps recording system in the Mitaka Correlation Center. All VERA antennas were

connected with the IVS network immediately due to this observation mode. This observation mode

was operated 9 times during 2007.

Joint observations with the 11m telescope of Gifu University started in October. The telescope

is linked to Mitaka via optical fiber and it is possible to record Gifu data by using a DIR2000 1

Gbps recorder at Mitaka.

4. Plans for 2008

Regular VERA Internal geodetic observations, the participation in JADE and 1 Gbps recording

according to JADE schedule will be continued. Gifu 11m antenna will join semi-regularly the

VERA internal observations in K-band and will be able to be regarded as the fifth station of

VERA at least for geodetic purposes. Experimental observations with Tsukuba 32m antenna in

the same mode will also be made.

Plans other than observations are improvement of software, such as model update and GUI,

and improvement and automization of data analyses.

5. Staff Members

The VERA team of NAOJ consists of 9 scientists, 7 technicians, and 5 post-docs. Among

them, the members of the geodesy group are S. Manabe (chief, scientist), Y. Tamura (scientist),

T. Jike (scientist), and M. Shizugami (software technician).

IVS 2007 Annual Report 71
Noto VLBI Station Istituto di Radioastronomia INAF, Stazione VLBI di Noto

Noto Station Status Report

G. Tuccari

Abstract

This brief report summarizes the main activities of the Observatory of Noto in 2007.

1. Antenna, Receivers and Microwave Technology

At present the main issue for the antenna functionality is still the azimuth rail, but news from

INAF indicate that the rail and grout replacement could be realized in 2008. If confirmed, this

job will probably stop the antenna activity during 2008 summer.

A new antenna driving software has been realized, which is able to support all the functionalities

available with the TIW ACU and is able to control with better precision. The new software has

also a Web interface.

The 43 GHz receiver is working with only one polarization and the replacement of a front-end

amplifier will be done in the next months.

The 86 GHz is still an issue. Functionality measurements will be done in laboratory and a new

campaign will be realized during the first months 2008.

2. Acquisition Terminal and Digital Technology

Terminals are in the process of being sent to the stations. On November 5, 2007 a geodetic

version of DBBC arrived in Wettzell. The Wettzell DBBC system has 4 IFs and 14 equivalent

base band converters. In the same month it was installed and integrated with the other VLBI

equipment. Recording of its output is realized by a Mark 5B+ system. Europe90 observation has

been done for testing the equipment. Fringes have been found on all channels and data analysis

in underway.

The DBBC system for Irbene (Latvia) has been completed and in the first days of February it

will be transferred by Latvian colleagues to their station. The Irbene DBBC is a reduced version

having two IFs and 2 Core1 boards. As soon as Irbene funds are available to upgrade the system,

a few Core2 boards will be added to achieve a complete architecture. At present the system will

allow to perform the first observations and tests of the antenna and the 6 cm receiver.

A system similar to the Irbene one has been delivered to the Arcetri Observatory. Main

purpose is to use it as a development system for FPGA configurations devoted to the realization of

spectrometer, pulsar, total power, and polarimetry back-end. The Arcetri team is part of a FPGA

team established to support firmware development on the DBBC platform.

Two additional DBBC systems are almost ready and equipped with 4 IF sections, but waiting

for the production of the new Core2 boards. Such terminal for Tigo and O’Higgins will be equipped

with four Core2 boards each and will achieve the functionality of 16 equivalent BBCs.

Other complete systems are under construction for Yebes, Noto, Medicina, and SRT. In particular the Medicina unit is expected to support the multibeam 22GHz receiver (7 feeds x 2 polarization

x 2 GHz bwd/ea) for VLBI and single dish applications.

The first ADB2 board prototype has been completed and is available for the first test. The

board offers several operation modes with demultiplexing in two or four bus. Maximum sampling

72 IVS 2007 Annual Report
Istituto di Radioastronomia INAF, Stazione VLBI di Noto Noto VLBI Station

clock is 2.2 GHz, maximum signal frequency to be sampled is 3.5 GHz, 10-bit representation. A

board ADB2 can feed as piggy-back element a FiLa10G, giving the possibility to place the sampling

element in the receiver site, connecting the DBBC through optical fibres.

The new processing unit Core2 board, in V5 version, is expected by the end of January for the

first tests. The board is compatible with ADB1 and ADB2 and support a minimal equivalent of

four Core1 functionality. A piggy-back element can be adopted for additional functionality, like

memory bank for pulsar de-dispersion, memory corner or other needs where a significant memory

addition is to be adopted. The memory piggy-back is under development.

A multiband fixed tuning configuration is under development and expected in March 08, to be

used as an alternative to the standard base band converter configurations.

The FiLa10G boards realization started and the first prototype of the board is expected in twothree months. It can be used as piggy-back board of any ADB2 sampler, giving the possibility to

transmit and receive at the same time a high data rate of 20 Gbps + 20 Gbps. The bidirectional

functionality can be required for instance when an RFI mitigation is needed to be realized in

a remote location with respect to the sampling and processing site. With a typical sampling

frequency of 2.048 MHz and the full 10-bit data representation, a double optical fibre set meets

the full requirement. Two transceivers can be used, with the possibility to populate the board

even with one transceiver only. One board can even support the data tx-rx of 2x2 VSI connections

and in such case it can still be used as p-b element of an ADB2 or as stand-alone element. Indeed

the configuration files can be also loaded by the on-board stand-alone flash memory. The entire

triangle connectivity HSI/HSIR to VSI in/VSI out to Optical Fibres is supported.

3. Observation Test, Documentation and More

The Europe89 was observed for 12 hours in September using 8 BBC equivalent in X band

and 3 BBC equivalent in S band: fringes have been detected in all the sub-bands. (See figure 1.)

Euro90 observed 24 hours at Wettzell with all the standard number of subchannels. A technique

to compensate for fractional frequency offset is under evaluation.

The digital system use requires to optimize or to equalize the IF flatness in band: a new version

of Conditioning Module is under development to optimize this aspect, but a good equalized band

is expected from the receiver. An additional observation test will be realized with the Wz unit

and all the other terminals that will be available at that time.

Dedicated Web pages have been added to the Noto Internet server with information about the

DBBC system. A document series is in preparation and it started to become available on these

pages, so as a page with News.

The integration with the Field System is now under development and expected to be accomplished in the coming weeks. It is realized initially as a collection of station commands, as the

software structure the DBBC is able to recognize. The gain information in the different parts of

the instrument are recorded in a log that can be available under a specific FS command request

for calibration purposes.

4. Geodetic Experiments in Noto during 2007

Noto station observed twelve geodetic experiments during 2007, namely 6 EUROPE, 3 IVSCRF, 2 IVS-T2, 1 IVS-R&D.

IVS 2007 Annual Report 73
Noto VLBI Station Istituto di Radioastronomia INAF, Stazione VLBI di Noto

Figure 1. Fringes from Europe89.

74 IVS 2007 Annual Report
Geodetic Institute, Norwegian Mapping Authority Ny- ̊Alesund 20 Metre Antenna

Ny- ̊Alesund 20 Metre Antenna

Helge Digre

Abstract

For the year 2007, the 20-meter VLBI antenna at the Geodetic Observatory Ny- ̊Alesund has tried to

participate in VLBI experiments at the scheduled level and has done 73 of 79 24-hour experiments. Ny-

 ̊Alesund has also participated in an e-VLBI test and in e-VLBI experiments, transferring experiment

data from Ny- ̊Alesund to the Haystack Correlator and later to the Bonn Correlator. Ny- ̊Alesund has

done 14 of 19 Intensive experiments. The reasons for the lost experiments were the personnel situation,

problems caused by an error in the main power delivery, and a lack of Mark 5 modules at the station.

In 2007, Ny- ̊Alesund has continued to feel some consequences of the reduction in maintenance support

and the lack of operator presence, both of which were caused by the reduction in staff that came as

a result of the general reduction in the Norwegian Mapping Authority’s (NMA) budgets. For 2007,

Ny- ̊Alesund was a two person station until June, when Jan-Ivar Tangen’s contract ended. The station

was closed for three weeks for summer holiday and became a three person station again in September.

In August, a new, second operator, Inge Sanden, was employed and started his training, while in

September, a new, third operator, Ole Bjørn  ̊Ardal, was employed and started his training. At the

beginning of the year, maintenance and repair were done at a minimum level, given the personnel

situation, and no responses were made to any alarms, and no errors were corrected during unmanned

operation. Towards the end of the year, the station was normally manned while experiments were

running, as long as all employees were present in Ny- ̊Alesund. Ny- ̊Alesund is a Mark 5 station only.

1. General Information

The Geodetic Observatory of the NMA at 78.9 N and 11.87 W is located in Ny- ̊Alesund, in

Kings Bay, at the west side of the island Spitsbergen, the biggest island in the Svalbard archipelago.

In 2007, Ny- ̊Alesund was scheduled for 79 R1, EURO, RD, and RDV experiments and 19 K07

Intensives. Some X-band experiments were totally cancelled because of systems being down. For

the same reason, one X-band experiment ran only 13 hours. Some X-band experiments lost up to

15 hours observing time due to alarms during unmanned operation. Two experiments ended early,

and up to 6 hours of observing time were lost because of the installation of e-VLBI equipment.

Most of this lost observation time was caused by lack of maintenance and reduction of personnel.

In addition to the 20-meter VLBI antenna, the Geodetic Observatory has two GPS antennas in

the IGS system and a Super Conducting Gravimeter in the Global Geodynamics Project (GGP)

installed on the site. There is also a CHAMP GPS and a SATREF (dGPS) installation at the

station. At the French station in Ny- ̊Alesund, there is a DORIS station. In October 2004 a GISTM

(GPS Ionospheric Scintillation and TEC Monitor) receiver was installed at the Statens Kartverk

structure in the context of ISACCO, an Italian research project on ionospheric scintillation observations, led by Giorgiana De Franceschi of the Italian Institute of Volcanology and Geophysics

(INGV).

2. Component Description

The antenna is intended for geodetic use and is designed for receiving in S-band and X-band.

The equipment is Mark 5. The station configuration file can be found on the IVS web site:

ftp://ivscc.gsfc.nasa.gov/pub/config/ns/nyales.config. Ny- ̊Alesund is located so far north that it

has daytime aurora in winter and midnight sun from the 20th of April to the 27th of August. The

IVS 2007 Annual Report 75
Ny- ̊Alesund 20 Metre Antenna Geodetic Institute, Norwegian Mapping Authority

Figure 1. Ny- ̊Alesund antenna.

location of the antenna enables signal reception over the North Pole. In 1998, Ny- ̊Alesund was the

only antenna that could receive signals from the Mars Global Surveyor for 24 hours.

3. Staff

Table 1. Staff related to VLBI operations at Ny- ̊Alesund.

Hønefoss: Section manager: Rune I. Hanssen (through September)

Line Langkaas (from October)

Station responsible at Hønefoss: Svein Rekkedal

Ny- ̊Alesund: Station commander: Leif Morten Tangen1/ Helge Digre

Engineer Jan-Ivar Tangen to 2007.06.30

Engineer Inge Sanden from 2007.08.01

Engineer Ole Bjørn  ̊Ardal from 2007.09.01

1Leif Morten Tangen was granted permission from 2006.11.01 until 2008.03.01. Leif Morten Tangen delivered his

resignation in November 2007 and will have a last period in Ny- ̊Alesund from 2008.02.11 to 2008.03.13.

76 IVS 2007 Annual Report
Geodetic Institute, Norwegian Mapping Authority Ny- ̊Alesund 20 Metre Antenna

Helge Digre participated in the TOW 2007.

4. Current Status and Activities

Ny- ̊Alesund has tried to participate in VLBI experiments at the scheduled level and has done

so, mostly as a tag-along station. Ny- ̊Alesund is a Mark 5A only station. Both the FS and Mark

5 are upgraded to the latest software versions. Two new FS computers were bought last year,

and some modifications and testing still must be done before they can be used permanently for

experiments. The communication problem with the receiver has been solved. What still remains

is a communication problem with the weather station. A direct high-speed data link from Ny-

 ̊Alesund Geodetic Observatory to MIT Haystack has been tested. The high-speed data link was

supposed to be able to transfer 100 Mbps. The Ny- ̊Alesund high-speed data link project is a

cooperative effort between NMA, UNINETT, NORDUnet, NASA Goddard Space Flight Center,

and MIT Haystack Observatory. The responsible person at NMA was Rune I. Hanssen. In the

second half of 2007, e-VLBI has been used for transferring the K07 measurements from Ny- ̊Alesund

to Bonn Correlator.

The Super Conducting Gravimeter (SCG) placed on the same fundament as IGS-GPS NYA1

has been running without problems. The yearly service on the system was performed by Dr.

Yoshiaki Tamura and Ove Omang in the middle of August. National Astronomical Observatory of

Japan, Mizusawa VERA Observatory, which owns the SCG, lent this equipment to NMA starting

on 2007.04.01, to keep the recording of the data going. The Geodetic Observatory, Ny- ̊Alesund, was

scheduled to use the last part of 2007 to again become fully manned with three people, operating

on a normal basis.

5. Future Plans

Ny- ̊Alesund will continue to participate in the 80 regular and 53 Intensive experiments for

which the antenna is scheduled, and it intends to move from tag-along status to fully operational

from the start of 2008. Ny- ̊Alesund is likely to participate in CONT 2008. We hope that the

new Field System computers, which in fact are not so new anymore, will be put into permanent

use as soon as possible, as the last of the communication problems was solved the second week of

2008. The National Astronomical Observatory of Japan, Mizusawa VERA Observatory, is lending

the Norwegian Mapping Authority their superconducting gravimeter, which is already installed in

Ny- ̊Alesund, so the scientific measuring series can continue. The SCG has to be refilled with liquid

Helium each year, and the lift has to be re-certified every year. The insulation in the roof of the

Observatory has absorbed a lot of moisture. The plan is to renovate the roof and build a better

solution during the summer of 2008, so that similar problems can be avoided in the future.

IVS 2007 Annual Report 77
German Antarctic Receiving Station (GARS) O’Higgins BKG – Wettzell

German Antarctic Receiving Station (GARS) O’Higgins

Wolfgang Schl ̈uter, Christian Pl ̈otz, Reiner Wojdziak

Abstract

In 2007 the German Antarctic Receiving Station (GARS) in O’Higgins contributed to the IVS

observing program with eight observation sessions. Control software and hardware have been improved

with the goal of implementing remote observations.

1. General Information

The German Antarctic Receiving Station (GARS) is jointly operated by the Federal Office of

Cartography and Geodesy (BKG) and the German Aerospace Center (DLR). The Institute for

Antarctic Research Chile (INACH) coordinated the preparatory activities and logistics prior to

the campaigns. The 9m radiotelescope at O’Higgins is used for geodetic VLBI and for downloading

of remote sensing images from satellites such as ERS and TerraSAR. The access to the station is

organized campaignwise during the Antarctic spring and summer. In 2007 the station was occupied

from January to March and from October to December. DLR and BKG jointly send engineers and

operators for the campaigns together with a team which maintains the infrastructure, such as the

provision of power.

Over the last years, special flights with “Hercules”-aircrafts and small TwinOtters-aircrafts

were organized by INACH in close collaboration with the Chilean Army, Navy, and Airforce and

with the Brasilian Airforce in order to transport the staff, the technical material and also the food

for the entire campaign from Punta Arenas via station Frei at King George Island to the station

O’Higgins on the Antarctic Peninsula. Only a few times, the staff and material were transported

by ship to O’Higgins. Due to the fact that the conditions for landing on the glacier have become

unpredictable, requiring a lot of security precautions, the employment of ships for transportation to

O’Higgins has become more and more important. As a consequence of global warming, the glacier

is melting. During the summer period, landing with TwinOtters airplanes has become impossible.

Arrival time and departure time is strongly dependent on the weather conditions and on general

logistics. Today more time to travel from Punta Arenas to O’Higgins has to be considered.

At the end of 2007, the cruiseliner “Explorer” sank approximately 50 miles away from

O’Higgins. This disaster affected the second campaign dramatically, as all the means of transportation were employed for the rescue of the passengers. The staff had to stay more than 10 days

longer at O’Higgins.

After the long Antarctic winter usually the equipment at the station has to be initialized. Damages, which result from the strong winter period, have to be identified and repaired. Shipment of

spare parts or material for upgrades from Germany needs careful preparation in advance.

In co-location with the 9m radiotelescope for VLBI

• two GPS receivers are operated in the frame of IGS all over the year, an Alan Osborn ACT

(OHI2), which has a long and stable history and a JAVAD receiver (OHI3) for GPS and

GLONASS tracking. During the second campaign 2007 the ACT receiver was replaced by a

second JAVAD receiver in order to provide redundancy for the GLONASS tracking.

78 IVS 2007 Annual Report
BKG – Wettzell German Antarctic Receiving Station (GARS) O’Higgins

• a tide gauge is installed, which has been operating for several years with some interruptions

caused by destroyed cables from the scratching ice on the rocks. During 2007 the system

failed. A replacement by a radar tide gauge system is planned.

• a meteorological station provides pressure, temperature, humidity and wind information, as

long as the extreme conditions outside do not disturb the sensors,

• a H-Maser, an atomic Cs-clock, a GPS time receiver, and a Total Accurate Clock (TAC) are

employed for the provision of the time and frequency.

The 9m radiotelescope is designed for dual purposes:

• for performing geodetic VLBI and

• for receiving the remote sensing data from ERS 2, JERS, and ENVISAT.

In the second campaign 2007, remote sensing data from TerraSAR were recorded with highest

priority.

Figure 1. View to GARS O’Higgins

Figure 2. Transport to Base Frei at King George Island with Hercules C-130

IVS 2007 Annual Report 79
German Antarctic Receiving Station (GARS) O’Higgins BKG – Wettzell

Figure 3. Bridge to Base O’Higgins

2. Technical Staff

The staff members who operate, maintain, and upgrade the GARS VLBI component and the

geodetic devices are summarized in table 1.

Table 1. Staff – members

Name Affiliation Function Working for

Christian Pl ̈otz BKG/FESG electronic engineer O’Higgins (responsible), RTW

Reiner Wojdiak BKG software engineer O’Higgins, IVS Data Center Leipzig

3. Observations in 2007

GARS participated in the following sessions of the IVS observing program during the Antarctic

summer campaign (January-March 2007)

• IVS T2049 06.-07. February 2007

• IVS OHIG48 07.-08. February 2007

• IVS OHIG49 13.-14. February 2007

• IVS OHIG50 14.-15. February 2007

and during the Antarctic spring campaign (October-December 2007)

• IVS OHIG51 11.-12. November 2007

• IVS OHIG52 12.-13. November 2007

• IVS OHIG53 18.-19. November 2007

• IVS OHIG54 19.-20. November 2007

The observations were recorded with Mark 5A. The data were carried from O’Higgins to Punta

Arenas by the staff when they returned home. From Punta Arenas, the disks were shipped by

regular air transports to the correlator.

80 IVS 2007 Annual Report
BKG – Wettzell German Antarctic Receiving Station (GARS) O’Higgins

4. Maintenance

The extreme conditions in the Antarctic require special attention to the GARS telescope and

to the infrastructure. Corrosion results in problems with connectors and capacitors, which need to

be detected. The H-Maser has to be set up into its operation mode as soon as the operators arrive.

The antenna, the S/X-band receiver, the cooling system, and the data acquisition system have

to be activated properly. Those components that were damaged during the previous campaign

usually are replaced. In 2007 two new containers were shipped to O’Higgins to replace worn out

systems and to improve the infrastructure, in particular renewing the personal cabins.

5. Technical Improvements

As already reported, the Antenna Control Unit (ACU) was replaced by a completely new system

built by VERTEX. Due to some inconsistencies in the operations, the old ACU was still used in

2006 for the observations in order to avoid failures during the VLBI experiments. At the beginning

of the first campaign 2007, final tests of the new ACU were successfully carried out. Consequently

the new ACU replaced the old system. Thanks to the new ACU and the Mark 5 recording system,

remote control of the antenna became more realistic. New software developments that make use of

direct access to shared memory following the server–client principle were made. This requires less

data transmission via Internet, making the software much more robust. Tests were carried out at

the end of the field campaign, during the wait for the transport to the mainland. Such a remote

system will support the remote monitoring of GARS in the future.

6. Upgrade Plans for 2008

During 2008 it is planned to increase the observing capabilities, in particular by extending the

period of observation, employing the remote control facilities. Such an upgrade will be realized

in close collaboration with DLR, which will make use of the facilities throughout the year for the

acquisition of data from the planned TerraSAR-Tandem mission. The Internet capabilities will be

improved. The upgrade to Mark 5B and the installation of Digital Baseband Converters (DBBC)

is planned for 2008.

IVS 2007 Annual Report 81
Onsala Space Observatory (OSO) Onsala Space Observatory (OSO)

The IVS Network Station Onsala Space Observatory

R ̈udiger Haas, Gunnar Elgered

Abstract

We briefly summarize the status of the Onsala Space Observatory in its function as an IVS Network

Station. The activities during the year 2007, the current status, and future plans are described.

1. Staff Associated with the IVS Network Station at Onsala

The staff associated with the IVS Network Station at Onsala remained mainly the same as

reported in the IVS Annual Report 2006 [1]. However, one Ph.D. student left the observatory

during the year, one new Ph.D. student joined the observatory, and one of the operators left.

Table 1. Staff associated with the IVS Network Station at Onsala. The complete telephone numbers start

with the prefix +46-31-772.

Function Name e-mail telephone

Responsible P.I.s R ̈udiger Haas rudiger.haas@chalmers.se 5530

Gunnar Elgered gunnar.elgered@chalmers.se 5565

Observatory director Hans Olofsson hans.olofsson@chalmers.se 5520

Ph.D. students Martin Lidberg (until 2007.11.30) lidberg@oso.chalmers.se 5566

involved in VLBI Tobias Nilsson tobnil@chalmers.se 5575

observation Tong Ning (since 2007.09.01) tong.ning@chalmers.se 5578

Field system Bi ̈orn Nilsson biorn@oso.chalmers.se 5557

responsibles Michael Lindqvist michael@oso.chalmers.se 5508

VLBI equipment Karl- ̊Ake Johansson karlake@chalmers.se 5571

responsibles Leif Helldner helldner@chalmers.se 5576

VLBI operators Roger Hammargren rogham@chalmers.se 5551

Fredrik Blomqvist (until 2007.08.31) blomqvist@oso.chalmers.se 5552

Telescope scientists Lars EB Johansson lars.johansson@chalmers.se 5564

Lars Lundahl lars.lundahl@chalmers.se 5559

2. Geodetic VLBI Observations for IVS during 2007

In 2007 the observatory was involved in the five IVS-series EUROPE, R1, T2, RDV, and RD07.

In total, Onsala participated successfully in 27 experiments. See Table 2. All experiments were

recorded on Mark 5 modules, and for many experiments the data were transferred by e-VLBI to

the Bonn correlator [2] using the PCEVN-computer [3]. The latter is daisy-chained to the Mark

5 computer to allow us to record in parallel on Mark 5 modules and the PCEVN raid-system and

also to simultaneously transfer the data in real-time from the PCEVN to the correlator. In the

second half of 2007 we upgraded the PCEVN raid-system to a capacity of 2 TB, i.e. large enough

for most of today’s IVS experiments.

Radio interference due to UMTS mobile telephone signals continued to interfere with S-band

observations.

82 IVS 2007 Annual Report
Onsala Space Observatory (OSO) Onsala Space Observatory (OSO)

Table 2. Geodetic VLBI experiments at the Onsala Space Observatory during 2007.

Exper. Date e-VLBI transfer Remarks

EURO-85 01.08 no o.k.

R1-258 01.09 yes, real-time o.k.

R1-260 01.22 no o.k., spurs in X-band

R1-262 02.05 yes, real-time o.k.

T2-049 02.06 yes, real-time o.k., noisy S-band phase cal

R1-263 02.12 yes, real-time o.k., clock jump -1 sec

R1-265 02.26 yes, real-time o.k., encoder problems, 6 scans lost

R1-270 04.02 no o.k., encoder problems, 4 scans lost

R1-271 04.10 no o.k., noisy phase cal

R1-273 04.23 no o.k., encoder problems, 14 scans lost

R1-274 05.02 yes, off-line o.k.

RD07-04 06.27 no o.k.

EURO-88 07.03 yes, off-line o.k.

RDV-64 07.10 no o.k.

RD07-05 07.11 no o.k., spurs in X-band, encoder problems, about 22 scans lost

R1-285 07.16 yes, off-line o.k., encoder problems, 18 scans lost

R1-291 08.27 yes, off-line o.k., X-band spurs, RX problems, encoder problems, 2 scans lost

EURO-89 09.03 yes, off-line o.k., spurs in X-band, encoder problems, 3 scans lost

R1-292 09.04 no o.k., spurs in X-band

R1-293 09.10 yes, off-line o.k., spurs in X-band, encoder problems, some scans lost

RD07-07 09.12 no o.k., spurs in X-band, encoder problems, some scans lost

R1-294 09.17 no o.k., spurs in X-band, encoder problems, 14 scans lost

R1-295 09.24 yes, off-line o.k., power failure, 4 hours lost

EURO-90 11.22 yes, off-line o.k.

T2-052 11.27 yes, off-line o.k.

RDV-66 12.05 no o.k.

RD07-10 12.12 no no correlator report yet

The previously reported problems with the azimuth encoders [4] continued partly during 2007,

and a power failure in September caused a loss of about 4 hours of observations. See Table 2.

The new S/X receiver with dual polarization was installed in early July. Unfortunately the

filters proved not to be good enough, and spurious phase cal signals affected the first couple of

X-band channels for several experiments. See Table 2. To avoid these disturbances, an additional

filter for right circular polarization was installed in November.

3. Fennoscandian-Japanese Ultra-rapid dUT1 Measurements

Together with our colleagues in Mets ̈ahovi, Kashima and Tsukuba, we started a project for

Fennoscandian-Japanese ultra-rapid dUT1 measurements in order to determine dUT1 with very

low latency. The project involves real-time data transfer from Fennoscandia to Japan, near realtime data conversion from Mark 5 to K5, near real-time correlation with the Japanese software

correlator, creation of VLBI databases, and quick data analysis. It allows the determination of

dUT1 within 30 minutes after the end of an observing session, as demonstrated by the baselines

Onsala—Kashima and Onsala—Tsukuba. See Table 3.

IVS 2007 Annual Report 83
Onsala Space Observatory (OSO) Onsala Space Observatory (OSO)

Table 3. Fennoscandian-Japanese ultra-rapid dUT1-experiments involving Onsala in 2007.

Exper. Date Stations Mbps tranfer Correlation Comments/latency

u7093a 04.03 Onsa - Kash 256 off-line off-line dUT1 within 3 hours

u7113 04.23 Onsa - Kash 128 real-time off-line dUT1 within 2 hours

u7122 05.02 Onsa - Kash 128 real-time real-time correlation within 10 minutes

u7150 05.30 Onsa - Kash 128 real-time real-time dUT1 within 28 minutes

u7151a 05.31 Onsa - Kash 128 real-time real-time dUT1 within 30 minutes

u7155 06.04 Onsa - Kash 256 real-time real-time dUT1 within 31 minutes

u07195 07.14 Onsa - Kash 128 real-time off-line

u07196 07.15 Onsa - Kash 256 real-time off-line

u7298 10.25 Onsa - Kash 256 real-time off-line

a07326 11.22 Onsa - Tsuk 256 real-time real-time dUT1 within 30 minutes

b07326 11.22 Onsa - Tsuk 256 real-time real-time

u7330a 11.26 Onsa - Kash 128 real-time off-line

u7330b 11.26 Onsa - Kash 256 real-time off-line

u7330c 11.26 Onsa - Kash 512 real-time off-line

u7330d 11.26 Onsa - Kash 128 real-time real-time dUT1 within 25 minutes

u7330e 11.26 Onsa - Kash 256 real-time real-time dUT1 within 27 minutes

u7330f 11.26 Onsa - Kash 512 off-line off-line

u7348a 12.14 Onsa - Kash 128 real-time real-time dUT1 within 30 minutes

u7348b 12.14 Onsa - Kash 256 real-time off-line

4. Monitoring Activities in 2007

The monitoring of the vertical height changes of the telescope tower by the invar monitoring

system at the 20 m telescope [5] was continued.

We also continued the calibration campaign for the Onsala pressure sensor [1]. For this purpose we borrow a Vaisala barometer from the Swedish Meteorological and Hydrological Institute

(SMHI). This instrument is calibrated once per year at SMHI. We do parallel manual recordings

with the SMHI barometer (Vaisala-SMHI), the Onsala barometer (Setra Systems) that has been

used for VLBI for many years, and another Vaisala barometer (new-Vaisala) that was installed in

2007 at the observatory as part of a new weather station. Figure 1 shows time series of differences

between these three sensors and the corresponding amplitude spectra.

The microwave radiometer Astrid was repaired during 2007. The microwave radiometer Konrad

was out of service during 2007. We expect Konrad to be in routine operation again in 2008.

The observatory hosts a gravimeter platform, which has been used for repeated absolute gravity

measurements for several years. In May three absolute gravity observation teams visited the

observatory—from the University for Environment and Life Sciences at  ̊As, Norway; the Institut

f ̈ur Erdmessung, University of Hannover, Germany; and the Swedish National Land Survey.

During 2007 we started preparing for the installation of a superconducting gravimeter at the

observatory. The house for the new gravimeter is expected to be constructed during spring 2008,

and the actual superconducting gravimeter is expected to be delivered mid-2008.

84 IVS 2007 Annual Report
Onsala Space Observatory (OSO) Onsala Space Observatory (OSO)

Figure 1. Top: pressure differences (a) Setra - Vaisala-SMHI, (b) Setra - new-Vaisala, (c) Vaisala-SMHI -

new-Vaisala. Bottom: corresponding amplitude spectra. The annual period is indicated as a vertical line.

5. Outlook and Future Plans

The Onsala Space Observatory will continue to operate as an IVS Network Station and to

participate in the IVS observation series. For the year 2008 a total of 25 experiments in the

series EUROPE, R1, T2, RDV, and RD08 are planned. We will also prepare to participate in

a possible CONT08 campaign. We aim at an increased and regular use of e-VLBI data transfer

using the PCEVN. We will continue to monitor the relevant VLBI system parameters to be able

to detect possible error sources as early as possible and to achieve and maintain high data quality.

This monitoring activity includes the stability of the telescope, the local tie, the pressure sensor

calibration and the operation of microwave radiometers. The new superconducting gravimeter is

expected to be in service in the second half of 2008.

References

[1] Haas, R., and Elgered, G.: The IVS Network Station Onsala Space Observatory. In: D. Behrend and

K. D. Baver (eds.): IVS 2006 Annual Report, NASA/TP-2007-214151, 81–84, 2007.

[2] Haas, R., Wager, J., Mujunen, A., Ritakari, J., M ̈uskens, A., Dulfer, C., Bertarini, A.: e-VLBI data

transfer from Onsala and Mets ̈ahovi to the Bonn correlator. In: J. B ̈ohm, A. Pany, and H. Schuh

(eds.): Proceedings of the 18th European VLBI for Geodesy and Astrometry Working Meeting, Geowissenschaftliche Mitteilungen, Schriftenreihe der Studienrichtung Vermessung und Geoinformation,

Technische Universit ̈at Wien, 79, 27–32, 2007.

[3] Ritakari, J., and Mujunen, A.: A VSI-H Compatible Recording System for VLBI and e-VLBI. In:

N.R. Vandenberg and K.D. Baver (eds.) IVS 2002 General Meeting Proceedings, NASA/CP-2002-

210002, 128–131, 2002.

[4] Haas, R., and Elgered, G.: The IVS Network Station Onsala Space Observatory. In: D. Behrend and

K. D. Baver (eds.): IVS 2005 Annual Report, NASA/TP-2006-214136, 111–114, 2006.

[5] Elgered, G., and Haas, R.: Geodetic Very-Long-Baseline Interferometry at the Onsala Space Observatory 1997–1998. In: W. Schl ̈uter and H. Hase (Eds.): Proc. of the 13th Working Meeting on European

VLBI for Geodesy and Astrometry, 60–64, 1999.

IVS 2007 Annual Report 85
Sheshan Shanghai Astronomical Observatory, CAS

Sheshan VLBI Station Report for 2007

Xiaoyu Hong, Qingyuan Fan, Tao An

Abstract

This report summarizes the observing activities carried out at the Sheshan station in 2007. The

SESHAN25 radio telescope participated in ten 24-hour VLBI sessions organized by the IVS and twentyseven VLBI experiments organized by the EVN. Apart from its international VLBI activities, the

SESHAN25 telescope spent a large amount of time on the Chinese Lunar Project, including the testing

before the launch of the Chang’E-1 satellite, and the tracking campaign after the launch. We also

report the updates and developments in the facilities at the station.

1. General Information

The Sheshan VLBI station (also named SESHAN25 in the geodetic community) is hosted by

the Shanghai Astronomical Observatory (SHAO), CAS. A 25-meter radio telescope, which was

built in 1987, is in operation at multiple centimeter wavelengths. The Sheshan VLBI station is a

member of the IVS, EVN, and APT. It takes part in astrometric, geodetic, and astrophysical VLBI

experiments, along with other VLBI network stations. In October and November 2007, SESHAN25

was involved in the VLBI tracking of the Chinese Chang’E-1 Lunar satellite. A 5-station correlator

at SHAO undertook the VLBI data processing of the Chang’E satellite.

2. VLBI Observations in 2007

In 2007, SESHAN25 participated in 10 IVS sessions. The antenna worked normally in 9 of

the experiments. SESHAN25 also participated in the EVN sessions in February and June at 1.3,

6, and 18 cm wavelengths. There were no known problems during the EVN observations. In

order to participate in the Chinese Chang’E Lunar Project, SESHAN25 stopped international

VLBI activities on October 11, 2007. After the launch of Chang’E-1 on October 24, the telescope

carried out daily monitoring of the satellite. The Chinese radio telescopes had great success in the

VLBI tracking of the Chang’E-1 satellite. The 5-station correlator processed the real-time data

transferred from the observing stations through fiber link. The outputs of delay, delay rate, and

the angular positions (RA and DEC) were used for measuring and determining the satellite orbit.

Since December 2007, SESHAN25 has observed the Chang’E-1 satellite in its lunar orbit two or

three days per week.

3. Development and Maintenance of Facilities in 2007

One of the antenna bearings was broken during the observation of IVS-R1288 on August 6. It

cost us a couple of weeks to replace the bearing and repair the drive. After that, we spent several

days on adjusting the pointing.

In August 2007, we received eight BBCs and one IF distributor from the IVS. The Shanghai

VLBI station then recovered the standard geodetic VLBI setup with 14 BBCs and 2 IF distributors.

We had a new Mark 5A system as a backup in 2007. The FS software package has been kept

up-to-date; the current FS version 9.9.2 is in use. A new FS computer was purchased for debugging local station programs. We have updated the clock and weather data acquisition programs

86 IVS 2007 Annual Report
Shanghai Astronomical Observatory, CAS Sheshan

and developed a remote monitoring program. The power equipment in the observing dome was

reconstructed to guarantee safe and smooth running during VLBI experiments.

A number of e-VLBI test experiments between Shanghai and some European stations were

performed in the first half of 2007. The Sheshan station can normally work at a data rate of

256 Mbps. In a demo experiment in Xi’an, China on August 28, Sheshan station achieved a

maximum data rate of more than 512 Mbps, and fringes were detected among Chinese, European,

and Australian telescopes.

Our five-station hardware correlator currently works at 16 Mbps per station in real-time mode,

and 256 Mbps per station for post processing. An e-VLBI system consisting of four Chinese radio

telescopes (in Shanghai, Urumqi, Beijing, and Kunming) and a software correlator were developed.

The e-VLBI facilities are used in the Chang’E project.

4. The Staff of the Sheshan VLBI Station

Table 1 lists the group members at the Sheshan VLBI Station. The staff is involved in the

VLBI program at the station with various responsibilities. Professor Wenren Wei retired in the

beginning of 2007, but he will continue working with us in 2008. Bin Li began to serve as the

technical friend at Sheshan station in 2007.

Table 1. The staff at the Sheshan VLBI Station.

Name Background Position & Duty Contact

Xiaoyu Hong astrophysics Director, Astrophysics xhong@shao.ac.cn

Qingyuan Fan ant. control Chief Engineer, Antenna qyfan@shao.ac.cn

Wenren Wei electronics Professor, VLBI terminal wwr@shao.ac.cn

Zhuhe Xue software Professor, VLBI terminal, FS zhxue@shao.ac.cn

Quanbao Ling electronics Senior Engineer, VLBI terminal qling@shao.ac.cn

Weihua Wang astrophysics Associated Professor, Astrophysics whwang@shao.ac.cn

Tao An astrophysics VLBI friend, Astrophysics antao@shao.ac.cn

Hong Yu ant control Associated Professor, Antenna yuhong@shao.ac.cn

Bin Li microwave Technical friend, receiver bing@shao.ac.cn

Jinqing Wang electronics Engineer, Antenna jqwang@shao.ac.cn

Huihua Li electronics Engineer, VLBI terminal hhlee@shao.ac.cn

Lingling Wang software Engineer, VLBI terminal llwang@shao.ac.cn

Rongbing Zhao software Engineer, VLBI terminal rbzhao@shao.ac.cn

Bo Xia electronics Operator bxia@shao.ac.cn

Wei Gou electronics Operator gouwei@shao.ac.cn

5. Prospects

From January 2008 on, the Sheshan VLBI Station will participate again in IVS and EVN

observations. In 2008 SESHAN25 will participate in 16–20 IVS sessions. The telescope will

regularly monitor the Chang’E-1 satellite in its lunar orbit for 2–3 days per week in 2008.

IVS 2007 Annual Report 87
Simeiz Station Radio Astronomy Lab of Crimean Astrophysical Observatory

Simeiz VLBI Station—New Status

A. E. Volvach, D. Graham

Abstract

We summarize briefly the status of our 22-m radio telescope as an IVS Network Station. In 2007

RT-22 was equipped with a modern Mark 5A VLBI recording system by the National Academy of

Sciences of Ukraine. That makes it possible to continue astrophysical and fundamental geodetic VLBI

observations.

1. General Information

Figure 1. The Simeiz VLBI station.

The Simeiz VLBI Station (also known as CRIMEA in the geodetic community), operated by

Radio Astronomy Laboratory of Crimean Astrophysical Observatory of the Ministry of Education

and Sciences of Ukraine, is situated on the coast of the Black Sea near the village of Simeiz, 20

km west of Yalta in the Ukraine.

88 IVS 2007 Annual Report
Radio Astronomy Lab of Crimean Astrophysical Observatory Simeiz Station

The RT-22 radio telescope has a steerable parabolic mirror of diameter 22 m and focal length

9 525 mm. The surface has rms accuracy of 0.25 mm and effective area 210 m2independent of

elevation angle. The antenna has an azimuth-elevation mounting with axis offset −1.8 ± 0.2 mm.

The maximal slewing rate is 1.5

◦/sec. The telescope control system provides a pointing accuracy

of 10′′.

The foundation pit of the telescope is 9 meters deep and contains 3 meters of crushed stones

and 6 meters of concrete. The height of the elevation axis above the foundation is 14.998 meters.

The telescope is located 80 meters from the edge of the Black sea.

The parameters of the 22 meter radio telescope are presented in Table 1.

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 is South) -270 ± 270

in Elevation, degrees 0 - 85

The control system of the radio telescope allows the antenna to be pointed and allows the

observed source to be tracked in two regimes: autonomous and automatic. All modes of the radio

telescope operation—antenna motion, radiometer readings, and data recording—are controlled by

the special host computer in automatic regime.

The 2 and 8 GHz receivers and the phase and the amplitude calibration units are installed in

the primary focus of the antenna. Table 2 shows the parameters of the 2 and 8 GHz receivers.

Table 2. The receiver parameters of the Simeiz antenna.

Band Frequency, GHz Tsys, K Treceiver, K Tfeed, K Tmainlobe, K Tsidelobes, K

S 2.1 - 2.5 100 40 25 7 28

X 8.18 - 8.68 80 50 5 10 15

The LNA was developed and manufactured by Joint-Stock “Mirrad” with the assistance of the

Crimean Astrophysical Observatory and the Main Astronomical Observatory NASU.

The LNAs are uncooled. The feed illuminates the main dish of the antenna over the angle 140◦

at the level -10 db.

IVS 2007 Annual Report 89
Simeiz Station Radio Astronomy Lab of Crimean Astrophysical Observatory

System Equivalent Flux Density (SEFD) was measured using radio sources with known flux

densities: Cas-A, Virgo-A, Cygnus-A, and Taurus-A. All measurements of system noise were made

using the Field System.

SEFDs were measured as 1100 (X) and 1400 (S) Jy at zenith, which essentially does not differ

from the values achieved with the former cooled amplifier.

The weight on the focus legs was reduced from 300 to 3 kg. This significantly eases the process

of putting up receivers.

A new pointing model was made with the upgraded receivers.

2. Current Status and Activities

The interdepartmental center for collective use of the RT-22 radio telescope was created within

the framework of the Scientific-Research Institute “Crimean Astrophysical Observatory” of the

Ukrainian Ministry of Education.

Organizational members of the Center are the Scientific-Research Institute “Crimean Astrophysical Observatory” (Director of SRI “CrAO”—A. M. Rostopchina-Shakhovska), the Main

Astronomical Observatory of National Academy of Sciences of Ukraine (Director of MAO—

Academician NASU Ya. S. Yatskiv) and the Institute of Radio Astronomy of National Academy

of Sciences of Ukraine (Director of IR—Academician NASU L. N. Litvinenko).

The purpose of this Center is an intensification and coordination of the main scientific research in the fields of astrophysics, astrometry, and geodynamics; more complete and effective

development and use of instrument possibilities and scientific potential of the national property

of Ukraine RT-22 as one of the best radio astronomy instruments of millimeter range; and the

effective integration and coordination of facilities and capabilities of the SRI “CrAO”, MAO, and

IR.

The main objectives of the Center are: development of new methods of scientific research in

radio astronomy; to provide a place for the scientific organizations of Ukraine and other countries

to carry out research and development with the scientific state-of-the-art equipment under the auspices of the staff of organizations and participants of the Center; organization and implementation

of fundamental, applied scientific research; realization of innovative and educational activity, and

foreign relations.

Scientific establishments and organizations that need the scientific equipment of the Center

to carry out research in either of two observing periods ending January 15 and June 15 should

submit a written application for hours, terms, and types of research to the Center. The observation

council considers annual plans for the distribution of observation time and introduces them for

consideration to the Center administration.

Head of the Center: Volvach Alexandr Evgen’evich, PhD, deputy director of SRI CrAO, tel.

+38-0654-23-71-52, e-mail: volvach@crao.crimea.ua.

Observation council Chairman: Vavilova Irina Borisovna, PhD, scientific secretary CSR NASU,

tel. +38-044-239-74-90, e-mail: vavilova@nas.gov.ua.

Contact information is provided at the URL: http::/www.crao.crimea.ua/rt22/main.htm

In 2007 RT-22 was equipped with a modern Mark 5A VLBI recording system by NAS Ukraine.

That will allow the continuation of astrophysical and fundamental geodetic VLBI observations.

On November 22, 2007 Mark 5A was made operational, and the first session (EUROPE-90) was

carried out.

90 IVS 2007 Annual Report
Radio Astronomy Lab of Crimean Astrophysical Observatory Simeiz Station

Table 3. The current projects.

Very Astrophysics, geodetics, astrometry and radar

Long projects with the international networks.

Baseline Facilities for VLBI observations at frequencies

Interferometry 612 MHz and 1.6, 2.3, 5.0, 8.4, and 22 GHz are available.

These observations are supported by the hydrogen

frequency standard with the stability 10−14

in the interval 1-24 hours and recording

systems Mark 5A and NRTV.

Multi-wavelength Regular monitoring is carried out at

monitoring of AGN frequencies 22.2 and 36.8 GHz.

Molecular line Observations in molecular lines of maser sources,

observations star forming regions, and other objects have been

at mm wavelength intensively carried out since 1978 in the

range of 1.6 to 115 GHz.

Solar and stellar Station carries out the observations at 8.6, 10.7,

activity investigations 13.3, 15.4, 22.2, and 36 GHz. Stokes parameters

of polarization I (intensity) and V (circular

polarization) are measured.

During 2007 the Simeiz station regularly participated in various radio astronomy programs

including VLBI and single-dish observations of quasars and planets.

3. Future Plans

Our plans for the coming year are the following: to put into operation the Mark 5B+ VLBI

recording system and to obtain a new H-maser.

4. Acknowledgments

Authors would to like to thank the Director of MAO, Academician NASU—Ya. S. Yatskiv;

the Director of IR, Academician NASU—L. N. Litvinenko; Deputy Director of IR, Academician

NASU—V. M. Shulga; and the Director of SRI “CrAO”—A. M. Rostopchina-Shakhovska for their

effort in creating the interdepartmental center for collective use of the radio telescope RT-22.

IVS 2007 Annual Report 91
Svetloe Station Institute of Applied Astronomy of Russian Academy of Sciences

Svetloe Radio Astronomical Observatory

Sergey Smolentsev, Ismail Rahimov

Abstract

This report summarizes information on recent activities at the Svetloe Radio Astronomical Observatory (SvRAO). During the previous year a number of changes were carried out at the observatory

to improve some technical parameters and upgrade some units to required status. The report provides

also an overview of current geodetic VLBI activities and gives an outlook for the next year.

1. Introduction

Svetloe Radio Astronomical Observatory (SvRAO) (Figure 1) was founded by the Institute of

Applied Astronomy (IAA) as the first station of the Russian VLBI network QUASAR. The VLBI

network QUASAR is described in [1].

Figure 1. Svetloe observatory.

The sponsoring organization of the project is the Russian Academy of Sciences. SvRAO is

located at the Karelian Neck, near Svetloe village, about 100 km north of St. Petersburg. The

basic instruments of the observatory are the 32-m radio telescope RT-32 and technical systems

provided for doing VLBI observations.

During last year, the Svetloe observatory participated regularly in various radio astronomical

programs including VLBI and single dish observations of quasars and planets.

2. Participation in IVS Observational Programs

During 2007 the Svetloe IVS station participated in 46 24-hour IVS-R4, IVS-T2, EURO, R&D

and VLBA sessions and in 15 IVS-Intensive sessions. A list of the sessions is presented in 1.

3. Radio Telescope

The railway junctures were joined by electric welding.

92 IVS 2007 Annual Report
Institute of Applied Astronomy of Russian Academy of Sciences Svetloe Station

Table 1. List of IVS sessions observed at SvRAO in 2007.

Month IVS-R4 IVS-T2 EURO R&D VLBA IVS-Intensive

January 3 1 1 2

February 2 1 2

March 5 2

April 4 1 2

May 5 1

June 3

August 1

September 3 1

October 5 2

November 4 1 2

December 4 2

Total 39 1 3 1 1 15

4. Co-location GPS

• The GLONASS/GPS receiver “PROTON” was installed as a GLONASS “Control station”

in December.

• A TopCon GPS/GLONASS/GALILEO receiver was bought and tested for future installation

in place of the Leica GPS receiver.

5. Outlook

Our plans for the coming year are the following:

• Participation in IVS-R1, IVS-R4, IVS-T2, EURO, VLBA and R&D observational sessions.

• Participation in the IVS CONT08 observation campaign.

• Participation in domestic observational programs for obtaining Earth orientation parameters.

• Continued geodetic control of the antenna parameters.

References

[1] Site http://www.ipa.nw.ru.

IVS 2007 Annual Report 93
JARE Syowa Station 11-m antenna National Institute of Polar Research

JARE Syowa Station 11-m Antenna, Antarctica

Koichiro Doi, Kazuo Shibuya

Abstract

The operation of the 11 m S/X-band antenna at Syowa Station (69.0◦S, 39.6◦E) by the Japanese

Antarctic Research Expeditions (JAREs) started in February 1998 and continues till today (January

2008). The number of quasi-regular geodetic VLBI experiments attained 77 at the end of 2007. Syowa

Station will participate in six OHIG sessions in 2008.

Data of five OHIG sessions in 2007 were recorded on hard disks through the K5 terminal. They

will be brought back from Syowa Station to Japan in April 2008. Data of OHIG44 to OHIG49 sessions

observed by JARE47 in 2006 are now being transferred to Bonn Correlator directly by using one of

NICT’s servers. Analysis results obtained from the data until OHIG43 session indicate that baseline

length between Syowa and Hobart is increasing with a rate of 53.8 ± 0.5 mm/yr and the one between

Syowa and HartRAO is also increasing with a rate of 11.5 ± 0.4 mm/yr.

1. Overview

Syowa Station has become one of the key observatories in the southern hemisphere geodetic

network, as reported in [1]. As for VLBI, the Syowa antenna is registered with 66006S004 as the

IERS Domes Number, and with 7342 as the CDP Number. Basic configuration of the Syowa VLBI

front-end system did not change from the description in [2].

K5 recording system was introduced to Syowa Station in September 2004. Syowa’s recording

terminal K4 was fully replaced by K5 simultaneously with the termination of the SYW sessions

at the end of 2004. Syowa participated in the OHIG sessions in the austral summer season of

2007. Data transfer through Intelsat satellite link from Syowa Station to NIPR became possible

according to the introduction of K5 system, but huge VLBI data transfer is not realistic because

of the low transfer speed.

2. Notes on System Maintenance

There is no significant problem in the “mechanical system”. The hydrogen maser set (Anritsu

RH401A; 1002C) was used for the observations from 2004 to 2007. JARE-48 (2007-2008) reinstalled 1001C at Syowa Station; the maser was brought back to Syowa Station in January 2007

after a major overhaul. A backup video-converter was also brought to Syowa Station by the JARE48. The tube in the Cs frequency comparator and local oscillator has to be replaced with a new

one in the near future.

3. Session Status

Table 1 summarizes the status of processing as of January 2008 for the sessions after 2004.

The SYW sessions consisted of Syowa (Sy), Hobart (Ho) and HartRAO (Hh). The OHIG sessions

involved the Fortaleza (Ft), O’Higgins (Oh), Kokee Park (Kk), Parkes (Pa), TIGO Concepcion

(Tc), and Syowa (Sy) antennas. In 2005, Syowa joined the CRD sessions, but after 2006, Syowa

participated only in OHIG sessions. The number of OHIG sessions in which Syowa participated

during 2007 was five.

94 IVS 2007 Annual Report
National Institute of Polar Research JARE Syowa Station 11-m antenna

Until 2004, OHIG sessions’ data on K4 tapes from Syowa Station were copied to Mark IV

tapes at GSI and the Mark IV tapes were sent to the Mark IV Correlator for final correlation.

After introducing the K5 system, K5 hard disk data brought back from Syowa Station were ftp

transferred to MIT Haystack Observatory or Bonn Correlator through a NICT server and converted

to the Mark 5 format data there.

Figure 1. Syowa VLBI staff for JARE-48 (Feb. 2007 - Jan. 2008).

4. Staff of the JARE Syowa Station 11-m Antenna

• Kazuo Shibuya, Project coordinator at NIPR.

• Koichiro Doi, Liaison officer at NIPR.

• Takanobu Sawagaki (from Hokkaido University), Chief operator for JARE-47 (Feb. 2006 -

Jan. 2007).

• Hiroshi Ishii (from NEC), Antenna engineer for JARE-47.

• Naoki Arai (from Electric Navigation Research Institute), Chief operator for JARE-48 (Feb.

2007 - Jan. 2008). (right in Figure 1)

• Sachiko Nagashima (from MontBell Co., Ltd.) Operator for JARE-48. (center in Figure 1)

• Hitoshi Sugawara (from NEC), Antenna engineer for JARE-48. (left in Figure 1)

IVS 2007 Annual Report 95
JARE Syowa Station 11-m antenna National Institute of Polar Research

Table 1. Status of SYW and OHIG experiments as of January 2008

Code Date Station Hour Correlation Solution Notes

OHIG29 2004/Feb/10 Ho, Hh, Ft, Oh, Tc 24 h Yes Yes (J45)

SYW030 2004/Apr/07 Ho, Hh 24 h Yes Yes

SYW031 2004/Aug/18 Ho, Hh 24 h Yes Yes

OHIG32 2004/Oct/16 Ho, Hh, Ft, Oh, Kk, Tc 24 h No No

OHIG33 2004/Nov/09 Ho, Ft, Oh, Kk, Tc 24 h Yes Yes

OHIG34 2004/Nov/30 Ho, Hh, Ft, Oh, Kk, Tc 24 h Yes Yes

OHIG35 2004/Dec/08 Ho, Hh, Ft, Oh, Kk, Tc 24 h Yes Yes

SYW032 2004/Dec/13 Ho, Hh 24 h Yes Yes

OHIG36 2005/Jan/26 Ho, Hh, Ft, Oh, Kk 24 h Yes Yes

OHIG37 2005/Feb/02 Ho, Hh, Ft, Oh, Kk 24 h Yes Yes (J46)

OHIG38 2005/Feb/15 Ho, Hh, Ft, Oh, Kk 24 h Yes Yes

CRDS18 2005/Apr/11 Ho, Hh 24 h Yes Yes

CRDS19 2005/May/10 45, Hh 24 h Yes Yes

OHIG39 2005/Nov/08 Ho, Hh, Ft, Oh, Kk 24 h Yes Yes

OHIG40 2005/Nov/09 Ho, Hh, Ft, Oh, Kk 24 h Yes Yes

OHIG41 2005/Nov/16 Ho, Hh, Ft, Oh, Kk 24 h Yes Yes

OHIG42 2006/Jan/31 Ho, Hh, Ft, Oh, Kk, Tc 24 h Yes Yes

OHIG43 2006/Feb/08 Ho, Hh, Ft, Oh, Kk, Tc 24 h Yes Yes (J47)

OHIG44 2006/Feb/14 Ho, Hh, Ft, Oh, Kk, Tc 24 h Not yet Not yet

OHIG45 2006/Nov/07 Ho, Hh, Ft, Oh, Kk, Tc 24 h Yes Not yet

OHIG46 2006/Nov/14 Ho, Hh, Oh, Kk, Tc 24 h Not yet Not yet

OHIG47 2006/Nov/29 Ho, Hh, Ft, Oh, Kk, Tc 24 h Not yet Not yet

OHIG49 2007/Feb/13 Ho, Hh, Ft, Oh, Kk, Tc 24 h Not yet Not yet (J48)

OHIG51 2007/Nov/06 Ho, Ft, Oh, Kk, Tc 24 h Not yet Not yet

OHIG52 2007/Nov/07 Ho, Ft, Oh, Kk, Tc 24 h Not yet Not yet

OHIG53 2007/Nov/13 Ho, Hh, Ft, Oh, Kk, Pa, Tc 24 h Not yet Not yet

OHIG54 2007/Nov/14 Ho, Hh, Ft, Oh, Kk, Pa, Tc 24 h Not yet Not yet

(1) 45: DSS45

(J45) JARE-45: op K. Doi eng. K. Fukuhara (J46) JARE-46: op K. Egawa eng I. Okabayashi

(J47) JARE-47: op T. Sawagaki eng H. Ishii (J48) JARE-48: op N. Arai eng H. Sugawara

96 IVS 2007 Annual Report
National Institute of Polar Research JARE Syowa Station 11-m antenna

5. Analysis Results

At the end of 2007, 52 sessions from May 1999 through February 2006 have been analyzed

with the software CALC/SOLVE developed by NASA/GSFC. The data of 5 OHIG sessions from

OHIG44 through OHIG49 will be analyzed soon.

The length of the Syowa-Hobart baseline is increasing with a rate of 53.8 ± 0.5 mm/yr. The

Syowa-HartRAO baseline shows a slight increase with a rate of 11.5 ± 0.4 mm/yr. These results

agree approximately with those of GPS. We do not detect a significant change in the SyowaO’Higgins baseline. Detailed results from the data until the end of 2003 as well as comparisons

with the results from other space geodetic techniques are reported in [3].

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/TP2003-211619, 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 2007 Annual Report 97
TIGO Bundesamt f ̈ur Kartographie und Geod ̈asie - TIGO

Geodetic Observatory TIGO in Concepci ́on

Sergio Sobarzo, Cristobal Jara, Eric O ̃nate, Cristian Herrera, Carlos Verdugo, Hayo Hase,

Armin B ̈oer, Bernd Sierk

Abstract

2007 was the sixth year of TIGO operation with 107 successful 24-hour observations.

1. General Information

The operation of TIGO is based on an agreement between Chile and Germany, in which Universidad de Concepci ́on, Instituto Geogr ́afico Militar, and the Bundesamt f ̈ur Kartographie und

Geod ̈asie secured their cooperation until the end of 2011. This year Universidad del B ́ıo B ́ıo finishes its participation in the consortium; however the VLBI staff remains warranted. TIGO is

located near the Universidad de Concepci ́on, at longitude 73.025 degrees West, latitude 36.843

degrees South and at an altitude of 180 m, 500 kilometers south of Santiago, Chile’s capital.

2. Component Description

The IVS network station TIGOCONC is the VLBI part of the Geodetic Observatory TIGO,

which was designed to be a fundamental station for geodesy. Hence the VLBI radiotelescope is

co-located with an SLR telescope (ILRS site), a GPS/Glonass permanent receiver (IGS site), and

other instruments such as water vapor radiometer, seismometer, superconducting gravity meter

and absolute gravity meter.

The atomic clock ensemble of TIGO consists of 2 hydrogen masers, 3 cesium clocks and 3 GPS

time receivers realizing the Chilean contribution to the Universal Time scale (Circular T, BIPM).

The technical parameters of the TIGO radiotelescope as published in [1] have not changed.

In 2007 the entire TIGO computer network infrastructure was upgraded to 1 Gbps allowing

the testing of new e-VLBI protocols and algorithms. Now any existing limiting factor is located

outside TIGO facilities.

3. Staff

The VLBI group remained unchanged as compared to 2006. In 2007 the TIGO VLBI group

consisted of the persons listed in Table 1. In 2007, Hayo Hase was elected to be an IVS Network

Representative on the IVS Directing Board for a four-year term.

4. Current Status and Activities

During 2007 TIGO was scheduled to participate in 111 IVS experiments (see Table 2). The

four failed experiments were mainly associated with problems related to cooling.

Apart from the regular IVS observation load, the TIGO VLBI group is involved in three

development areas: e-VLBI, Remote Control User Interface for the FS and Sattrack testing.

98 IVS 2007 Annual Report
Bundesamt f ̈ur Kartographie und Geod ̈asie - TIGO TIGO

Figure 1. Current VLBI Staff (Jara, Sobarzo, Hase, Herrera, Verdugo and O ̃nate).

Table 1. TIGO VLBI support staff in 2007.

Staff Function Email

Hayo Hase head hayo.hase@tigo.cl

Sergio Sobarzo chief engineer sergio.sobarzo@tigo.cl

Cristobal Jara electronic engineer cristobal.jara@tigo.cl

Eric O ̃nate electronic engineer eric.onate@tigo.cl

Cristian Herrera informatic engineer cristian.herrera@tigo.cl

Carlos Verdugo mechanical engineer carlos.verdugo@tigo.cl

any VLBI-operator on duty vlbi@tigo.cl

all VLBI-operators vlbistaff@tigo.cl

Table 2. TIGO’s IVS observation statistics for 2007.

Name # of Exp. OK Failed

R1xxx 41 40 1

R4xxx 51 50 1

R&D 7 7 0

OHIGxx 7 6 1

T20xx 3 2 1

RDVxx 2 2 0

Total 111 107 4

4.1. e-VLBI

During 2007, TIGO continued its participation in the EXPReS project, which aims at connecting 21 VLBI radiotelescopes in 6 continents using high speed networks allowing real-time

IVS 2007 Annual Report 99
TIGO Bundesamt f ̈ur Kartographie und Geod ̈asie - TIGO

VLBI. The previously mentioned TIGO network upgrade was done to support the realization of

the objectives of this project.

TIGO also had presence at the 6th International e-VLBI Workshop held in Bonn, Germany on

September 17 and 18. Hayo Hase presented the development work of Sergio Sobarzo under the title

Multipath and Singlepath Routing for e-VLBI. This research aims at a new protocol, which will

allow that parallel flows of VLBI data can be sent over different routes using different constraints

resulting in an increase of the data transfer speed proportional to the number of alternative routes.

Also development work is being done to look into new algorithms for UDP congestion control and

congestion avoidance, which can be applied to e-VLBI data.

On July 12th, the First Research Virtual Communities Global Forum was held. TIGO, among

14 other research organizations, made an online presentation in the Networking session called

Connectivity of Chilean NREN.

4.2. Remote Control User Interface

New improvements were made to the Remote Control Software developed in 2005 (see [2]).

Now the client is a standalone application written in Python running in the Linux Graphical

Environment (see Figure 2).

Figure 2. Screenshot of the software for remote control VLBI operation with the Field System. The upper

part displays antenna status and receiver temperatures; in the middle there is an operator input area, and

at the bottom there is a live image of the telescope. Also there are tabs for Mark 5 status & schedule,

receiver status & weather, and log with additional information.

100 IVS 2007 Annual Report
Bundesamt f ̈ur Kartographie und Geod ̈asie - TIGO TIGO

4.3. Sattrack Testing

In January, Michael Moya, a visitor from Chalmers University of Technology in Gothenburg,

Sweden, made the final tests of the satellite tracking software at TIGO [3]. Since in the southern

sky there are not that many suitable radio sources to perform pointing tests, there was the need to

find a way to do these calibrations using artificial sources, like AQUA and TERRA, with carrier

signals inside the X-Band. (See Figure 3 for a successful observation.) The written software was

included in the FS station software and uses the North American Aerospace Defense Command

(NORAD) two line elements (TLE) as input. As a future work this software should be included

in the main distribution of the Field System.

Figure 3. Successful pointing on TERRA using sattrack software [3].

5. Future Plans

The VLBI activities in 2008 will focus on

• execution of the IVS observation program for 2008

• participation in the CONT08 campaign

• continuation of developments:

– investigations related to e-VLBI

– remote control user interface for the FS

– new monitor and control solution for the receiver

• repetition of the local survey

References

[1] Vandenberg, N.R.: International VLBI Service for Geodesy and Astrometry 1999 Annual Report,

NASA/TP–1999-209243, 1999.

[2] Gonzalo Remedi, Sergio Sobarzo and Hayo Hase, Remote Control of VLBI Operations, Proceedings of

the Fourth IVS General Meeting, 2006, pp 127-131.

[3] M. Moya Espinosa and R. Haas, SATTRACK A Satellite Tracking Module for the VLBI Field System,

Proceedings of the 18th European VLBI for Geodesy and Astrometry (EVGA) Working Meeting, 2007,

pp 53-58.

IVS 2007 Annual Report 101
Tsukuba 32-m VLBI Station Geographical Survey Institute, Japan

Tsukuba 32-m VLBI Station

Kensuke Kokado, Machida Morito, Shinobu Kurihara, Shigeru Matsuzaka

Abstract

Tsukuba 32-m radio telescope is operated by Geographical Survey Institute (GSI) VLBI group.

This report summarizes the current status and the future plans of Tsukuba 32-m VLBI station. We

had participated in a total of 164 domestic/international VLBI sessions scheduled at the beginning of

this year and some new sessions, such as INT3 and Ultra Rapid dUT1 experiments in 2007. All of the

observations have been performed with the K5/VSSP32 system. We had some troubles at our facility,

so we ran an overall check of the antenna. In the near future, we plan to do an overall maintenance.

AIRA

CHICHI10

TSUKUB32

SINTOTU3

The VLBI station of GSI

Figure 1. Tsukuba 32-m VLBI station and GARNET (GSI VLBI network).

1. General Information

The Tsukuba 32-m VLBI station (TSUKUB32) is located at GSI in Tsukuba Science City,

which is about 50 km to the northeast of the capital Tokyo. GSI has four VLBI stations:

TSUKUB32, AIRA, CHICHI10, and SINTOTU3. These four stations form our domestic VLBI

network named GARNET (GSI Advanced Radio telescope NETwork). We have performed our domestic VLBI observations using GARNET. A series of the observations is named JADE (JApanese

Dynamic Earth observation by VLBI). The main purposes of the JADE series are to define the

reference frame of Japan and to monitor the plate motions for the advanced study of crustal de102 IVS 2007 Annual Report
Geographical Survey Institute, Japan Tsukuba 32-m VLBI Station

formations. The GARNET stations, centered on TSUKUB32, are located to cover the Japanese

mainland.

2. Component Description

In March 2007, we finished the installation and adjustment of K5/VSSP32 [1], which enables

us to record at 32 Msps/ch. Since then, we have performed all domestic/international sessions

with the K5/VSSP32. After the installation, we moved the previous K5 system (K5/VSSP) to

VERAISGK station of NAOJ on Ishigaki Island. VERAISGK has participated in JADE sessions

throughout the year. At VERAISGK, we introduced a high-speed optical network. Now, we

transfer the data to Tsukuba at about 24 Mbps. We also renewed a Low Noise Amplifier (LNA)

for stable refrigeration of X-band receiver at TSUKUB32 station in December 2007.

We made a joint research agreement with Tsukuba University for installing a K-band receiver

at TSUKUB32 station. In test observations, we found a noise pattern of standing wave type in

the receiver system. Investigations revealed that the water resistant sheet for the feed horn of the

antenna reflects part of the radio wave, and that the reflected wave is the cause of the standing

wave. After we had changed the water resistant sheet to remove the standing wave, Tsukuba University performed some astronomical observations in December 2007. They succeeded in observing

recombination lines of ammonia molecules and ionized gas. Meanwhile, we implemented K-band

VLBI observations for finding fringes with KASHIM34 or GIFU11 station. We could find fringes

for the first time in May 2007.

Figure 2. K5/VSSP32 Figure 3. Change of the water resistant sheet

In 2007, we had some problems with the equipment of the station. One of the insulator panels

of the antenna was broken by strong wind and fell down to the ground on January 3rd. As a

result of immediate investigation, we found three more dangerous panels which lacked the fixation

screws. We reinforced these panels on March 23rd and ran an overall check of the antenna in May

IVS 2007 Annual Report 103
Tsukuba 32-m VLBI Station Geographical Survey Institute, Japan

2007, because other equipment might have a problem. Another problem was the hydrogen maser,

which went down twice (March and November). As we have two hydrogen masers at TSUKUB32

station, we could continue to participate in VLBI sessions switching the main hydrogen masers.

However, these masers have a short life expectancy because they were manufactured more than 10

years ago, so we will have to renew them in the near future.

3. Staff

Table 1 shows the regular operating staff of GSI’s VLBI observation group. Kazuhiro Takashima

(former leader of VLBI group) and Junichi Fujisaku (former operation chief) moved to different

departments in April. In their stead, Kozin Wada and Shinobu Kurihara came back to GSI VLBI

group after a few years interval. Yoshihiro Fukuzaki is in charge of the analysis of SYOWA experiments and a member of the IVS Directing Board (Networks Representative). Routine operation

were mainly performed under contract with Advanced Engineering Service Co., Ltd (AES), over

230 days in 2007. The information about the correlator staff are listed in the report of Tsukuba

VLBI Correlator in the correlator section of this volume.

Table 1. Staff list of the GSI VLBI group

Name Position

Shigeru MATSUZAKA Director of Space Geodesy Division

Kozin WADA Deputy Director of Space Geodesy Division

Shinobu KURIHARA Leader of VLBI group

Etsurou IWATA Network chief

Morito MACHIDA Operation chief

Kensuke KOKADO Technical staff (Observation and Analysis)

Daisuke TANIMOTO Technical staff (routine observation)

Yoshihiro FUKUZAKI Researcher, IVS DB

4. Current Status and Activities

The regular sessions are shown in Table 2. TSUKUB32 station participated in a total of 164

domestic/international VLBI sessions in 2007. We have conducted INT3 sessions since August

27th, 2007, with Ny- ̊Alesund and Wettzell every Monday. The aim is to obtain the UT1 estimate

within 24 hours after the session. Therefore, we adapt “e-VLBI” and “Tsunami” protocol which

is a UDP/IP based protocol developed by Advanced Network Management Laboratory of Indiana

University. We can transfer the data to Bonn correlator at about 300 Mbps using “Tsunami”. We

also use “Tsunami” to transfer the data to Bonn correlator in IVS-R sessions.

In addition, we had two special experiments in 2007. The first one was the intensive experiment

for ultra-rapid UT1 measurement. The goal of the experiment is to obtain the UT1 result within

30 minutes after the end of the last scan. The stations that participated in the experiment are

TSUKUB32, KASHIM34, ONSALA60, and METSAHOV, all with high-speed network connections. In the ultra rapid experiment, we used “Tsunami” protocol, because one of the key factors

104 IVS 2007 Annual Report
Geographical Survey Institute, Japan Tsukuba 32-m VLBI Station

to enable the rapid UT1 measurement is to transfer the data as fast as possible. We transfered the

data from the stations in Europe to Japan using the Tsunami protocol and the PC-EVN system.

We succeeded in obtaining the UT1 result within 1 hour after the end of the experiment with

ONSALA60 on November 22th, 2007.

The second was a special domestic VLBI experiment for geting more precise positions of the

Japanese VLBI stations. USUDA64 station of Japan Aerospace Exploration Agency (JAXA) and

YAMAGUCH station of Yamaguchi University participated in the experiment together with the

four stations of GSI. Further, we performed test observations for geodetic VLBI with UCHINOURA

station of JAXA. As we found fringes in X-band, we plan geodetic VLBI sessions for 2008. We

expect to get more precise positions of these stations by analyzing the data of these sessions. These

results will be used as reference positions for astronomical observations at these stations.

Table 2. The regular sessions at Tsukuba 32-m VLBI station in 2007

Sessions Code Number

IVS-R R1258,R1259 ... R1307,R1308 31

IVS-T T2052 1

VLBA RDV66 1

APSG APSG20,APSG21 2

JADE JD0701-0712 12

IVS-INT1 I07267,I07268,I07269 3

IVS-INT2 K07007,K07013 ... K07349,K07350 96

IVS-INT3 K07239,K07246 ... K07344,K07351 18

Total 164

5. Future Plans

At present, we make domestic observations in 8 MHz sampling mode, because the video convertors at participating stations cannot accept a wider band than 4 MHz. Therefore, we plan to

broaden the frequency range and will perform a fringe test in January 2008.

GSI VLBI group has made co-location surveys for connecting the result of VLBI observations

to the geodetic network at all of the GSI VLBI stations. We will conduct a second co-location

survey at TSUKUB32 station in February 2008.

References

[1] J. Fujisaku, S. Kurihara, K. Takashima: Tsukuba 32m VLBI station, IVS 2004 Annual Report, February 2005

[2] J. Fujisaku, K. Kokado, K. Takashima: Tsukuba 32m VLBI station, IVS 2005 Annual Report, April

2006

[3] K. Kokado, J. Fujisaku, K. Takashima: Tsukuba 32m VLBI station, IVS 2006 Annual Report, April

2007

IVS 2007 Annual Report 105
Nanshan Station Urumqi Observatory, NAO–CAS

Nanshan VLBI Station Report for 2007

Aili Yusup, Na Wang

Abstract

The Nanshan 25-meter radio telescope is operated by Urumqi Observatory. This report describes

the activities and the status of Nanshan VLBI station as an IVS network station in 2007.

1. Introduction

The station is located 70 km south of Urumqi, the capital city of Xinjiang Uygur Autonomous

Region of China. The station is affiliated with the Urumqi Observatory of the National Astronomical Observatories, CAS. We contribute to IVS in geodetic VLBI observations. The Nanshan

VLBI station has participated in domestic VLBI experiments and as one of the VLBI ground stations tracking the Chinese Chang’E satellite. Urumqi also participated in the Japanese SELENE

observation. The telescope participated in real-time experiments among the Chinese Network. We

are grateful for the kind help and support from the VLBI experts within the IVS. The Urumqi

Observatory is willing to continue the collaboration in international VLBI activities.

2. Telescope Status

2.1. Antenna

• Diameter: 25 meter

• Antenna type: Modified Cassegrain wave-guide

• Seat-rack type: Azimuth-pitching ring

• Main surface precision: 0.40 mm (rms)

• Pointing precision: 15” (rms)

• Rolling range: Azimuth: -270◦to 270◦; Elevation: 5◦to 88◦

• Maximum rolling speed: Azimuth: 1.0◦/sec; Elevation: 0.5◦/sec

2.2. Receiver

The basic specifications of the receivers are given in Table 1.

2.3. Recording System

Mark 5, Mark IV, Mark II, and K5 recording systems are available now at the Nanshan VLBI

station. The performance of the observing system has been improved over the last year. A new

FS computer is in use at Nanshan, and the Field System has been upgraded to version 9.9.2 and

works well. The p-cal control system has been updated, and the parameters of S/X band receivers

are sampled from the FS software.

106 IVS 2007 Annual Report
Urumqi Observatory, NAO–CAS Nanshan Station

Table 1. Specifications of receivers

Parameters Freq. Range

(MHz)

1.3 cm LCP Tsys=190K DPFU=0.057 22100–24000

3.6 cm RCP Tsys=110K DPFU=0.093 8100–8900

6 cm dual Tsys=22K DPFU=0.105 4700–5110

13 cm RCP Tsys=75K DPFU=0.096 2150–2450

18 cm dual Tsys=21K DPFU=0.088 1400–1720

30 cm LCP Tsys=160K DPFU=0.06 800–1200

49 cm dual Tsys=? DPFU=? 305–345 not tested yet

92 cm dual Tsys=? DPFU=? 560–660 not tested yet

2.4. Time and Frequency System

Nanshan’s no. 11 H-maser has been upgraded at ShAO, and it is in good status. The other

two H-masers, the No. 13 and the MHM2010 imported from the Symmetricom company in the

United States, work well. A new time and frequency system has operated continuously since its

installation at the Nanshan station in November 2005, and it works well.

3. Personnel

Table 2. The main staff at Nanshan VLBI Station

Name Position Working area e-mail

Na Wang Professor Station chief na.wang@uao.ac.cn

Aili Yusup Professor Chief engineer aliyu@uao.ac.cn

Zhengwen Sun Senior engineer Microwave, Receiver sunzw@uao.ac.cn

Xiang Liu Professor VLBI friend liux@uao.ac.cn

Yousuo Dong Senior engineer Antenna control dongys@uao.ac.cn

Maozheng Chen Senior engineer Receiver mzchen@uao.ac.cn

Aili Esamdin Scientist Astronomy aliyi@uao.ac.cn

Jarken Yesembek Scientist Astronomy jerken@uao.ac.cn

Weixia Wang Senior engineer Receiver wangwx@uao.ac.cn

Minghui Shao Senior engineer Time and Freq., Terminal shaomh@uao.ac.cn

Wenjun Yang Engineer Terminal yangwj@uao.ac.cn

Shiqiang Wang Engineer Antenna Wangshq@uao.ac.cn

Hua Zhang Engineer Terminal, Time and Freq. zhangh@uao.ac.cn

Guanghui Li Engineer Network, Computer ligh@uao.ac.cn

Jun Ma Engineer Receiver majun@uao.ac.cn

Chenyu Chen Engineer Antenna chency@uao.ac.cn

Xiangfeng Wang Engineer Network, Computer wangxf@uao.ac.cn

IVS 2007 Annual Report 107
Nanshan Station Urumqi Observatory, NAO–CAS

4. Nanshan Geodetic VLBI Observations during 2007

Nanshan participated in the following 6 geodetic VLBI sessions during 2007 as listed in table

3. All experiments were recorded using Mark 5A. The telescope has been kept in a good condition,

and all geodetic 24-hour experiments did well in 2007.

Table 3. Geodetic VLBI experiments observed by Urumqi Observatory during 2007.

Experiment Date Remarks (problems)

T2049 02.06 OK

T2050 05.15 OK

T2051 07.31 OK

T2052 11.27 OK

APSG20 09.11 OK

APSG21 10.10 OK

5. Future Plan

A new 1.3 cm dual polarization cryogenic receiver will be built in 2008. A dual band for both

92 cm and 49 cm receiver systems will be tested and used in 2008.

108 IVS 2007 Annual Report
MIT Haystack Observatory Westford Antenna

Westford Antenna

Mike Poirier

Abstract

Technical information is provided about the antenna and VLBI equipment at the Westford site of

Haystack Observatory, and about changes to the systems since the IVS 2006 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.

Figure 1. The radome of the Westford antenna.

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 spacecraft-deployed 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 in 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

IVS 2007 Annual Report 109
Westford Antenna MIT Haystack Observatory

and techniques now employed in geodetic VLBI worldwide. Primary funding for geodetic VLBI at

Westford is provided by the NASA Space Geodesy Program.

Table 1. Location and addresses of 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.

Figure 2. Wide-angle view of 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.

The antenna is enclosed in a 28-meter-diameter, air-inflated radome made of 1.2-mm-thick,

Teflon-coated fiberglass—see Figure 1. When the radome is wet, system temperatures increase by

110 IVS 2007 Annual Report
MIT Haystack Observatory Westford Antenna

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

10–20 K at X-band and by a smaller amount at S-band. The major components of the VLBI data

acquisition system are a Mark IV electronics rack, a Mark 5A recording system, and a Pentiumclass PC running PC Field System version 9.9.2. The primary frequency and time standard is the

NR-4 hydrogen maser. A CNS Clock GPS receiver system provides independent timing information

and comparisons between GPS and the maser. 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 an Ashtech Model-Z Reference Station receiver acquires the GPS data.

3. Westford Staff

The personnel associated with the VLBI program at Westford and their primary responsibilities

are:

Joe Carter antenna controls

Brian Corey VLBI technical support

Kevin Dudevoir pointing system software

Dave Fields technician, observer

Glenn Millson observer

Michael Poirier site manager

Alan Whitney site director

IVS 2007 Annual Report 111
Westford Antenna MIT Haystack Observatory

4. Status of the Westford Antenna

During the period 2007 January 1 through 2007 December 31, Westford participated in 62

24-hour geodetic sessions. Westford regularly participated in the IVS-R1, IVS-R4, IVS-R&D,

RD-VLBA, and T2 series of geodetic sessions as well as fringe tests, e-VLBI experiments, and

VLBI2010 wideband development testing.

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.

5. e-VLBI Development at Westford

Westford continues to play a key role in the development of e-VLBI. In 2007, Westford served

as a test bed for:

• continued high-speed e-VLBI development over a dedicated 10 Gbps link to Haystack Observatory and a new 10 Gbps link to the rest of the world,

• integration and testing of e-VLBI technology for the new Mark 5B system, and

• evaluation of new networking equipment for e-VLBI.

The outlook for Westford is that it will play a crucial role in e-VLBI development for VLBI2010

and the broadband development effort as data rates approach 4 Gbps.

6. Outlook

At Westford we anticipate being able to participate in 68 24-hour geodetic sessions in 2008

and to support occasional e-VLBI experiment fringe tests and VLBI2010 wideband development

testing.

112 IVS 2007 Annual Report
Forschungseinrichtung Satellitengeod ̈asie (FESG) Fundamentalstation Wettzell - 20m Radiotelescope

Fundamentalstation Wettzell - 20m Radiotelescope

Richard Kilger, Gerhard Kronschnabl, Wolfgang Schl ̈uter

Abstract

The 20m Radiotelescope in Wettzell, Germany contributed very successfully and strongly to the

IVS observing program again in 2007. Technical changes, improvements, and upgrades have been done

to increase the reliability of the entire VLBI observing system.

1. General Information

The 20m Radiotelescope in Wettzell (RTW) was designed in the years 1980/81 as a project of

the former “Sonderforschungsbereich 78 Satellitengeod ̈asie”. RTW is an essential component of the

Fundamentalstation Wettzell (FSW) and is jointly operated by Bundesamt f ̈ur Kartographie und

Geod ̈asie (BKG) and Forschungseinrichtung Satellitengeod ̈asie (FESG) of Technical University

Munich. In addition to the 20m RTW at the Fundamentalstation Wettzell (FSW) the following

geodetic space technique systems are co-located:

• WLRS (Wettzell Laser Ranging System), a laser ranging system designed for Satellite Laser

Ranging (SLR) and Lunar Laser Ranging (LLR) being involved in ILRS; at present, a new

laser Satellite Observing System (SOS-W) for low orbiting satellites is under construction.

• GPS receivers, involved in gloabl network IGS, in the European network EUREF, in the

national network GREF, and in time transfer experiments.

• G, a large lasergyroscope or ringlaser dedicated to monitoring daily variations of Earth

rotation.

A time and frequency system (T&F) is established for the generation of the timescale

UTC(IfAG) and for the provision of very precise frequencies needed for VLBI, SLR/LLR, and

GPS observations. Cs-clocks, H-Masers, and GPS time receivers are employed. The time scale

UTC(IfAG) is published in the monthly Bulletin T of BIPM. Additional in situ observations are

carried out, such as gravity observations with a super conducting gravity meter, recording of earthquakes with a seismometer, and meteorological observations to monitor pressure, temperature, and

humidity including wind speed, wind direction and rain fall. Water vapor observations are carried

out continuously with a Radiometrixs radiometer. Periodically, conventional geodetic control measurements are performed to tie the reference points of the space geodetic systems RTW, WLRS,

GPS, and “G” to the local terrestrial coordinate system and to investigate the local stability.

2. Staff

The staff of the Fundamentalstation Wettzell consists in total of 35 members for operations,

maintenance, and repair, for improvement of all devices, and for development of new systems.

Within the responsibility of the Fundamentalstation Wettzell are also the:

• TIGO systems (see TIGO report in this volume), operated in Concepci ́on, Chile by 3 BKG

experts jointly with a Chilean partner consortium (support staff: 11 engineers).

• O‘Higgins station (see O’Higgins report in this volume) in Antarctica, jointly operated with

the German Space Center (DLR) and the Institute for Antarctic Research Chile (INACH).

IVS 2007 Annual Report 113
Fundamentalstation Wettzell - 20m Radiotelescope Forschungseinrichtung Satellitengeod ̈asie (FESG)

Figure 1. 20m Radiotelescope in the rural environment

The staff operating RTW is summarized in table 1. At the end of October Richard Kilger

retired; nevertheless he continued to support the TWIN-project, improved the cooling system, and

participated in the O’Higgins observations. Dr. Alexander Neidhardt will take over his position

in May 2008. Alexander has background as an IT Engineer and currently works for the control

system of the new Laser Ranging System SOS-W, which is in its final stage to become operational.

Table 1. Staff - members of RTW

Name Affiliation Function Working for

Wolfgang Schl ̈uter BKG head of the FSW RTW, TIGO, O’Higgins, T&F,...

Richard Kilger FESG group leader RTW, retired October RTW

Erhard Bauernfeind FESG mechanical engineer RTW

Ewald Bielmeier FESG technician RTW

Gerhard Kronschnabl BKG electronic engineer RTW, TIGO and O’Higgins (partly)

Christian Pl ̈otz BKG/FESG electronic engineer O’Higgins, RTW (partly)

Raimund Schatz FESG software engineer RTW

Walter Schwarz BKG electronic engineer RTW, O’Higgins and WVR (partly)

Reinhard Zeitlh ̈ofler FESG electronic engineer RTW

Daniel Helmbrecht FESG/BKG student RTW

3. Observations in 2007

The 20m RT-Wettzell has supported geodetic VLBI activities for 25 years. All successfully

observed sessions in the year 2007 are summarized in table 2. According to the IVS 2007 Master

114 IVS 2007 Annual Report
Forschungseinrichtung Satellitengeod ̈asie (FESG) Fundamentalstation Wettzell - 20m Radiotelescope

Schedule, RTW ran more 24-hour geodetic VLBI sessions than any other IVS network station, as

it has for the last eight years. In addition to the 24-hour sessions, RTW continued to run the daily

one-hour INTENSIVE sessions in order to determine UT1-UTC. At the beginning of 1984, RTW

observed together with Westford, since 1995 with Greenbank and since 1999 with Kokee Park.

These sessions are called INT1 and are performed every weekday. The correlation is done at the

Washington Correlator (WACO). On Saturday and Sunday RTW participates in the INT2 sessions

together with Tsukuba, Japan, filling the weekend gap with data from Sunday morning to Monday

evening. Since August 2008, INT3 sessions were set up on Monday morning, in order to shorten the

weekend gap. INT3 includes the network stations Wettzell, Tsukuba and Ny- ̊Alesund. INT2 data

are correlated at the VLBI correlator in Tsukuba; INT3 data are correlated in Bonn. Both VLBI

correlators in Tsukuba and Bonn have a fast internet connection and are able to receive the data

from the observing stations via e-VLBI in near real time. INT2 and in particular INT3 provide

regular UT1-UTC results with the shortest latency. Some efforts to shorten the latency, which

is affected mostly by the data transfer between the stations and the correlator, have been made.

RTW has strongly improved its internet connection in 2007 from 34 Mbit/sec to 622 Mbit/sec.

Today the data transfer via Internet is extended to all correlators which already have fast internet

connections (Bonn, Tsukuba and Haystack). The data transfer via Internet to the Washington

Correlator is still organized via a center in the Washington area. The last mile problem is solved

by car transport to the correlator.

Table 2. RTW observations in 2007

program number of

24h-sessions

IVS R1 52 program number of

IVS R4 52 1h-sessions

IVS T2 4 INT1(Kokee-RTW) 213

IVS R&D 10 INT2(Tsukuba-RTW) 83

EUROPE 6 INT3(Tsukuba-RTW-Ny Al) 16

RDV/VLBA 6 in total 312

in total 132

In addition to the routine observations, some measurements were carried out to test the 1 Gbps

recording capabilities and to test the observation modes for the upcoming SELENE observations,

which are requested by the National Astronomical Observatory of Japan. SELENE is a Lunar

Project to improve the determination of the gravity field of the moon.

4. Technical Improvements and Maintenance

VLBI observations require high reliability at all participating stations; therefore careful servicing of all components is essential to ensure successfully performed VLBI measurements through

the year(s). Additionally the 20m RTW has to be kept on a high technical standard and has to

be improved according to technological advancement.

In 2007 the following actions were carried out:

• Implementation of an EVN PC for the data transmission to the Bonn correlator:

– Combining the EVN PC via VSIC-System with Mark 5A,

IVS 2007 Annual Report 115
Fundamentalstation Wettzell - 20m Radiotelescope Forschungseinrichtung Satellitengeod ̈asie (FESG)

– Extension of the Fieldsystem PC with software to record the data in parallel with Mark

5A and the EVN PC System,

– The EVN PC transfer is operationally employed for the INT3 data,

• Improvement of the Internet connection:

– Upgrading from 34 Mbps to 622 Mbps,

– Testing to verify the usable bandwidth, which shows best values of 500 Mbps,

– Installation of an additional backup server to improve the reliability,

– Installation of 6 TB storage capabilities for intermediate data handling of INT data and

R1 data,

• Development of a test bed for the RTW motor drives:

– for testing the status of the motors,

– for optimizing the drive units,

• Integration of the Digital Baseband Converters (DBBC):

– replacement of the analog baseband converters,

– improvement of RTW towards VLBI 2010 requirements,

• Inplementation of the hardware to support the Japanese SELENE Project:

– collaboration with the National Astronomical Observatory of Japan (NAO),

– test observations and preparation for tracking the Lunar Orbiter RStar and VStar,

• Fieldsystem Upgrade from Version FS 9.9.2 to FS 9.10.2

• Contributions to VLBI 2010:

– releasing the specifications for the new VLBI 2010 compatible telescope (TWINTelescope Wettzell TTW),

– requesting bids and contracting a company to manufacture the TWIN-telescopes,

– considering a broadband feed capable of receiving a frequency band from 1 to 18 GHz.

5. Plans for 2008

During 2008, plans are to maintain the standards in observing quality and quantity. Some

dedicated items will be:

• Final integration of the digital baseband converters (DBBC)

• Final integration of the Mark 5B-units

• Proceeding towards the realisation of the VLBI 2010 TWIN-Telescope.

116 IVS 2007 Annual Report
Observatorio Astron ́omico Nacional Observatorio Astron ́omico Nacional – Yebes

Observatorio Astron ́omico Nacional – Yebes

Francisco Colomer, Pablo de Vicente, Jes ́us G ́omez–Gonz ́alez,

Jos ́e Antonio L ́opez–Fern ́andez

Abstract

This report updates the description of the OAN facilities as an IVS network station. The new 40-m

radiotelescope has seen first light, and commissioning is in progress. First geodetic VLBI observations

are expected in 2008.

1. General Information: the OAN Facilities

The Observatorio Astron ́omico Nacional (OAN) of Spain is a department of the Instituto

Geogr ́afico Nacional (IGN, Ministerio de Fomento) and operates a new 40 meter radiotelescope

at Yebes (Guadalajara, Spain). The facility also includes an old 14-m radiotelescope, which has

been a network station of the IVS, participating regularly in the geodetic VLBI campaigns until

2003, and will now be refurbished to become a tracking station for the next space radiotelescope

VSOP-2.

Pictures of the radiotelescopes and of the Yebes site are available in the IVS Annual Reports

for 2005 and 2006. A satellite view can be found at the URL http://tinyurl.com/23ooly.

Yebes is also the reference station for the Spanish GPS network. A building has been finished

to hold the IGN gravimeters.

2. OAN Staff Working in VLBI Projects

Table 1 lists the OAN staff who are involved in VLBI studies, some of whom can be found

at the telescope (CAY) address. The VLBI activities are also supported by other staff such as

receiver engineers, computer managers, secretaries, and students. Moreover, we expect to contract

telescope operators in 2008.

Table 1. Staff in the OAN VLBI group (Email: vlbitech@oan.es).

Name Background Role Address

Francisco Colomer Astronomer VLBI Project coordinator OAN

Richard Dodson Astronomer Marie-Curie fellow OAN

Susana Garc ́ıa-Espada Engineer PhD student OAN

Jes ́us G ́omez–Gonz ́alez Astronomer General Subdirector for IGN

Astronomy, Geodesy and Geophysics

Jos ́e Antonio L ́opez–Fern ́andez Engineer CAY site manager CAY

Maria Rioja Astronomer Scientist (Astrometry) OAN

Pablo de Vicente Astronomer VLBI Technical coordinator CAY

IVS 2007 Annual Report 117
Observatorio Astron ́omico Nacional – Yebes Observatorio Astron ́omico Nacional

Figure 1. Photograph of the new X-band receiver, to be installed at the new 40-m radiotelescope.

Figure 2. Photograph of the new S/C/CH-bands receiver, installed at the new 40-m radiotelescope cabin.

118 IVS 2007 Annual Report
Observatorio Astron ́omico Nacional Observatorio Astron ́omico Nacional – Yebes

Table 2. Characteristics of the Yebes 40-m geodetic VLBI station.

Parameter Value DAR VLBA4 (14) + VSI-C

Diameter 40 meter Recorder Mark 5B

Receivers 2 - 115 GHz H-maser KVARTZ CH-1

S/X Tsys 100 K GPS TrueTime XL-DC

S/X SEFD expected 420 Jy Weather station SEAC-EMC

3. Status of the Geodetic VLBI Activities at OAN

The most important developments have been the construction of the S/X band receivers for

the 40-m radiotelescope (see Figures 1 and 2), as well as its commissioning and setup for VLBI.

All relevant equipment is already available at the Yebes site (e.g., VLBA4/VSI DAR, Mark 5B

recorder, H-maser, GPS receiver, weather station).

Thanks to a fruitful cooperation with the geodesy group at Onsala Space Observatory (Sweden),

we have re-analyzed the geodetic VLBI data of all campaigns where the old 14-m radiotelescope

at Yebes has participated using the best available apriori geophysical models. We compared in

particular the time series of station coordinates with the results from an analysis of the Yebes

GPS data. This work is part of the PhD thesis of Susana Garc ́ıa-Espada and, together with

planned local-tie measurements, is of major importance for the combination of the historic VLBI

observations performed with the 14-m radio telescope and the future observations with the new

40-m radio telescope.

4. Future Plans

The construction of a new building for the installation of permanent equipment for constant

gravity monitoring (FG5–number 211, and A-10–006 absolute gravimeters) is finished (see Figure

3). The construction of a network of concrete pillars around the 40-m radiotelescope to measure

its reference point and its local-tie to the old 14-m radiotelescope is delayed and will be performed

in 2008. Moreover, the Yebes site will get connected to GEANT at a rate of 1 Gbps thanks to the  ́

EC project EXPReS.

References

[1] Cordob ́es D., de Vicente P., Fern ́andez J., Almendros C., Yag ̈ue J.M. “Traslado de

los equipos de VLBI al radiotelescopio de 40m”. Informe T ́ecnico OAN 2007-1 (see

http://www1.oan.es/informes/archivos/IT-OAN-2007-1.pdf).

[2] de Vicente P., Gallego J.D., Bola ̃no R., Almendros C. “Monitorizaci ́on del m ́aser de hidr ́ogeno

antes y despu ́es del traslado al radiotelescopio de 40m”. Informe T ́ecnico OAN 2007-3 (see

http://www1.oan.es/informes/archivos/IT-OAN-2007-3.pdf).

[3] Cordob ́es D., de Vicente P., Bola ̃no R. “Software para corregir la deriva

del m ́aser ajustando su cavidad”. Informe T ́ecnico OAN 2007-4 (see

http://www1.oan.es/informes/archivos/IT-OAN-2007-4.pdf).

IVS 2007 Annual Report 119
Observatorio Astron ́omico Nacional – Yebes Observatorio Astron ́omico Nacional

Figure 3. Building at Yebes which will hold the gravimeters.

[4] de Vicente P., Almendros C. “Mark IV formatter upgrade with a VSI card”. Informe T ́ecnico OAN

2007-9 (see http://www1.oan.es/informes/archivos/IT-OAN-2007-9.pdf).

[5] Cordob ́es D., L ́opez-P ́erez J.A., Garc ́ıa-Garc ́ıa R., L ́opez-Fern ́andez J.A., Abad J.A., Mart ́ınez G.

“Dise ̃no, montaje y medida de ecualizadores para el receptor banda X”. Informe T ́ecnico OAN 2007-11

(see http://www1.oan.es/informes/archivos/IT-OAN-2007-11.pdf).

[6] de Vicente P., Bola ̃no R., Almendros C., Fern ́andez J., Abad J.A. “Upgrading the Mark 5A to Mark 5B”. Informe T ́ecnico OAN 2007-15 (see

http://www1.oan.es/informes/archivos/IT-OAN-2007-15.pdf).

[7] ETSIT Madrid. “Polarizador y acoplador de banda S para el radiotelescopio de 40 metros”. Informe

T ́ecnico OAN 2007-17 (see http://www1.oan.es/informes/archivos/IT-OAN-2007-17.pdf).

[8] Malo I., de Miguel A., Fern ́andez J., Abad J.A., Henche S., L ́opez-P ́erez J.A., Serna J.M., L ́opezFern ́andez J.A. “FI del Receptor S del Radiotelescopio de 40m del CAY”. Informe T ́ecnico OAN

2007-20 (see http://www1.oan.es/informes/archivos/IT-OAN-2007-20.pdf).

[9] Serna-Puente J.M., L ́opez-Fern ́andez J.A., Malo I., L ́opez-P ́erez J.A. “Medidas m ́odulo FI del

receptor banda X del Radiotelescopio de 40m del CAY”. Informe T ́ecnico OAN 2007-22 (see

http://www1.oan.es/informes/archivos/IT-OAN-2007-22.pdf).

[10] L ́opez-Fern ́andez J.A., Serna-Puente J.M., Malo I., Tercero F., Yag ̈ue J.M., Abad J.A., Fern ́andez

J. “Criostato de los receptores S/C/CH de la antena ARIES XXI del CAY”. Informe T ́ecnico OAN

2007-23 (see http://www1.oan.es/informes/archivos/IT-OAN-2007-23.pdf).

120 IVS 2007 Annual Report
Institute of Applied Astronomy of Russian Academy of Sciences Zelenchukskaya Station

Zelenchukskaya Radio Astronomical Observatory

Andrei Dyakov, Sergey Smolentsev

1. Abstract:

This report briefly summarizes the observing activities at the Zelenchukskaya 32-m VLBI station during the year 2007.

2. General Information

Zelenchukskaya Radio Astronomical Observatory was founded by 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 the Republic Karachaevo-Cherkessiya (Northern Caucasia)

about 70 km south of Cherkessk, near to the Zelenchukskaya site (not far from the Radiotelescope

RATAN-600). The geographic location of the observatory is shown on the IAA RAS Web site:

http://www.ipa.nw.ru/PAGE/koi8-r/DEPOBSERV/rus zel.htm

The basic instruments of the observatory are a 32-m radio telescope and technical systems for

doing VLBI observations.

Figure 1. Zelenchukskaya Observatory.

Table 1. Zelenchukskaya Observatory location and address.

Longitude 41◦34′

Latitude 43◦47′

Zelenchukskaya Observatory

Republic Karachaevo-Cherkessia

357140, Russia

ipazel@mail.svkchr.ru

IVS 2007 Annual Report 121
Zelenchukskaya Station Institute of Applied Astronomy of Russian Academy of Sciences

3. Technical and Scientific Information

The technical parameters of the radio telescope RT-32 and other Zelenchukskaya station equipment are presented in the 2005 Annual Report [1].

3.1. Co-location with GPS

A GPS ASHTECH Z-X113 receiver with an ASH 700936D M antenna Dorne-Margolin/Choke

Ring was installed at the observatory during 2006. Observed data are sent to BKG and IGS every

hour.

4. Radio Telescope

• The antenna rail was reconstructed by adding a steel supporting construction and rebuilding

the concrete under it (Figure 2).

Figure 2. Steel supporting construction under the rail.

• The antenna structure was painted in August 2007 (Figure 3).

Figure 3. Painting of antenna.

122 IVS 2007 Annual Report
Institute of Applied Astronomy of Russian Academy of Sciences Zelenchukskaya Station

5. Participation in the IVS Observing Program

Table 2 summarizes the sessions observed during 2007.

Table 2. List of IVS sessions observed at ZcRAO in 2007.

Month IVS-R1 IVS-R4 EURO R&D VLBA

January 1 3

February 1 3 1

March 3 1

April 1 3

May 1 1

October 4 1

November 4 1

December 1 4 1 1

Total 5 25 2 2 2

During 2007 the Zelenchukskaya IVS station participated in a total of 36 IVS-R1, IVS-R4,

EURO, R&D, and VLBA sessions.

6. Outlook

Our plans for the coming year are the following:

• Participation in IVS-R1, IVS-R4, IVS-T2, EURO, R&D, and VLBA observing sessions.

• Participation in the IVS CONT08 observing campaign.

• Participation in domestic observational programs for obtaining Earth orientation parameters.

• Putting into operation the cable length control system (“ground unit”).

• Upgrading the electronic part of the angle data unit.

References

[1] International VLBI Service for Geodesy and Astrometry 2005 Annual Report, NASA/TP-2006-214136,

154–157.

IVS 2007 Annual Report 123

Operation Centers

Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn IGGB Operation Center

The Bonn Geodetic VLBI Operation Center

A. Nothnagel, A. M ̈uskens

Abstract

The IGGB Operation Center has continued to carry out similar tasks of organizing and scheduling

various observing series as in 2006. The INT3 activities have been added in the second half of the year.

1. Center Activities

The IGGB Operation Center is located at 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 more than twenty years. The observing series organized and scheduled

in 2007 are the same as in 2006 but augmented with the INT3 activities.

• Measurement of Vertical Crustal Motion in Europe by VLBI (EUROPE)

In Europe, a series of special sessions has been scheduled for the determination of precise

station coordinates and for long term stability tests. This year, six sessions with Ny- ̊Alesund,

Onsala, Metsahovi, Svetloe, Zelenchukskaya, Badary, Effelsberg, Wettzell, Simeiz, Madrid

(DSS65A), Medicina, Matera, and Noto were scheduled employing the frequency setup of

16 channels and 4 MHz bandwidth in fan-out mode (identical to the setup of the IVS-T2

sessions).

• IVS-T2 series

This series has been observed roughly every third month (4 sessions in 2007) 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 at least once per year in the T2 sessions. In view of the limitations in

station days, priority was given to stronger and more robust networks with many sites over

more observing sessions. Therefore, 12 to 15 stations have been scheduled in each session

requiring multiple passes on the IVS correlators. 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):

Seven sessions of the Southern Hemisphere and Antarctica Series with the Antarctic stations

Syowa (Japanese) and O’Higgins (German) plus Fortaleza, Hobart, Kokee, HartRAO and

DSS45 have been organized for maintenance of the VLBI TRF and Earth rotation monitoring. These sessions are clustered in time at periods when O’Higgins is manned depending

on logistical circumstances and manpower available. The recording frequency setup is 16

channels and 4 MHz channel bandwidth.

• UT1 determination with near-real-time e-VLBI (INT3):

One of the main applications of the results of the IVS Intensive series is the prediction of UT1

values based on time series of existing UT1 observations. Reducing the latency in providing

UT1 results from observations does improve UT1 predictions significantly.

IVS 2007 Annual Report 127
IGGB Operation Center Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn

For this purpose another Intensive project was initiated to fill the gaps between the INT2

sessions on Sunday mornings and the INT1 sessions on Monday evenings. Under the short

name INT3, the telescopes of Ny- ̊Alesund, Tsukuba and Wettzell started to observe a new

series of one-hour Intensive sessions in August 2007. These sessions are scheduled to start

every Monday morning at 7:00 a.m. UT.

Figure 1. INT3 Network

In order to speed up delivery of the results, the raw VLBI observation data of the three sites

is transferred to the Bonn Correlator by Internet connections. For compatibility reasons,

the Tsukuba data, initially recorded in K4 format, has to be converted to Mark 5 format

after transmission. 16 channels with 8 MHz/channel are recorded resulting in 256 MBit/s.

With close to 30 minutes effective observing and recording time, each station has to transfer

about 460 GBit (or 58 GBytes) per session. Due to copying procedures and current network

capacities, completion of delivery of the raw VLBI data to the correlator is currently about

seven hours after the final observation.

2. Staff

Table 1. Personnel at IGGB Operation Center

Arno M ̈uskens +49-228-525264 mueskens@mpifr-bonn.mpg.de

Axel Nothnagel +49-228-733574 nothnagel@uni-bonn.de

128 IVS 2007 Annual Report
NASA Goddard Space Flight Center CORE Operation Center

CORE Operation Center Report

Cynthia C. Thomas, Daniel MacMillan

Abstract

This report gives a synopsis of the activities of the CORE Operation Center from January 2007 to

December 2007. The report forecasts activities planned for the year 2008.

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 in 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 station time and media dependent—as it has been for the past three years. The following are

the network configurations for the sessions for which the CORE Operation Center was responsible:

IVS-R1: 52 sessions, scheduled weekly and mainly on Mondays, six to eight station networks

RDV: 6 sessions, scheduled evenly throughout the year, 14 to 18 station networks

IVS-R&D: 10 sessions, scheduled monthly, five to seven station networks

2. IVS Sessions January 2007 to December 2007

This section displays the purpose of the IVS sessions for which the CORE Operations Center

is responsible.

• IVS-R1: In 2007, the IVS-R1s were scheduled weekly with six to eight station networks.

Ny- ̊Alesund, Westford, and Wettzell participated in most of the IVS-R1 sessions. Fortaleza

participated in several IVS-R1 sessions using 4 MHz bandwidth while the other stations used

8 MHz until the end of October. Fortaleza started using 8 MHz bandwidth during R1300

on October 29. Seshan participated in the IVS-R1 sessions with only 8 BBCs during 2007.

Both Ny- ̊Alesund and Zelenchukskaya were tagged along to all IVS-R1 sessions in which the

two stations participated.

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

the time delay from the end of recording to results as short as possible. The time delay goal

is a maximum of 15 days. Participating stations are requested to ship discs to the correlator

as rapidly as possible. 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 full 10-station VLBA plus up to 8 geodetic stations.

These sessions are being coordinated by the geodetic VLBI programs of three agencies: 1.

USNO will perform repeated imaging and correction for source structure; 2. NASA will

IVS 2007 Annual Report 129
CORE Operation Center NASA Goddard Space Flight Center

analyze this data to determine a high accuracy terrestrial reference frame; and 3. NRAO

will use 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 10 R&D sessions in 2007, as decided by the IVS Observing Program Committee, was to record at 1 Gbit/s data rate to evaluate the geodetic results for

sessions one through four. Those experiments also tested the entire data flow from scheduling

through analysis for the higher data rate. The purpose of the fifth session was to determine

polarization leakage in the receiver on the geodetic VLBI measurables. The purpose of the

sixth through tenth sessions was to test 512 Mbps recording mode for possible usage in the

CONT08 campaign.

3. Current Analysis of the CORE Operation Center’s IVS Sessions

Table 1 gives the average formal errors for the R1, R4, T2, and RDV sessions from 2007.

The R1 sessions have significantly better formal uncertainties in 2007 compared with 2006. RDV

uncertainties are worse in 2007 than 2006. This is probably due to the decrease in the number of

sites in the RDV sessions from 2006 (18-19 sites) to 2007 (15-16 sites).

Table 2 shows the EOP differences with respect to IGS for the R1, R4, and RDV series. The

level of WRMS agreement for the R1 and R4 sessions in 2007 is within 10-15% of the WRMS IGS

difference in 2006. The RDV WRMS IGS differences are larger than in 2006; however, it is difficult

to draw any statistically significant conclusions from these differences since there were only 5 RDV

sessions that were analyzed at the time of writing.

Table 1. Average EOP Formal Uncertainties for 2007

Session Type Num X-pole Y-pole UT1 DPSI DEPS

(μas) (μas) (μs) (μas) (μas)

R1 49 45(54) 43(52) 1.9(2.5) 82(111) 33(45)

R4 49 69(73) 73(72) 2.9(3.2) 162(166) 68(67)

T2 1 44(54) 49(55) 2.2(2.5) 107(126) 36(48)

RDV 5 50(40) 53(41) 2.8(1.9) 92(74) 41(31)

Values for 2006 are shown in parentheses

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.

130 IVS 2007 Annual Report
NASA Goddard Space Flight Center CORE Operation Center

Table 2. Offset and WRMS Differences (2007) 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 52 -20(7) 60(76) 4(15) 77(77) -1(-4) 19(17)

R4 52 -38(-35) 112(98) 10(36) 125(131) 2(-2) 22(21)

RDV 5 -10(31) 104(16) -140(22) 86(95) 7(-7) 22(12)

Values for 2006 are shown in parentheses

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

Irv Diegel Maser maintenance Honeywell

Mark Evangelista Receiver maintenance Honeywell

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

Leonid Petrov Analysis NVI, Inc./GSFC

David Rubincam Procurement of materials necessary for CORE

operations

GSFC/NASA

Dan Smythe Tape recorder maintenance Haystack

Cynthia Thomas Coordinate master observing schedule and

prepare observing schedules

NVI, Inc./GSFC

5. Planned Activities during 2008

The CORE Operation Center will continue to be responsible for the following IVS sessions

during 2008.

• The IVS-R1 sessions will be observed weekly and recorded in a Mark 5 mode.

• The IVS-R&D sessions will be observed 10 times during the year. The purpose of the R&D

sessions in 2008 as determined by the IVS Observing Program Committee is to continue the

series of 512 Mbps tests.

• The RDV sessions will be observed 6 times during the year.

IVS 2007 Annual Report 131
NEOS Operation Center at USNO U.S. Naval Observatory

NEOS Operation Center

Kerry Kingham, M.S. Carter

Abstract

This report covers the activities of the NEOS Operation Center at USNO for 2007. 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 IVSR4 observing session, on Thursday-Friday, for Earth Orientation, together with five daily onehour duration “intensives” for UT1 determination, Monday through Friday. The operational IVSR4 network has included VLBI stations at Kokee Park (Hawaii), Wettzell (Germany), Fortaleza

(Brazil), Ny- ̊Alesund (Norway), TIGO (Chile), Svetloe, Badary and Zelenchukskaya (Russia),

Hobart (Australia), Matera and Medicina (Italy), and Westford (USA). A typical R4 consisted of

6 to 7 stations.

The regular stations for the weekday IVS Intensives were Kokee Park and Wettzell. During

most of the year intensives including Kokee Park, Wettzell, and Svetloe were observed twice per

month in order to characterize the Kokee Park – Svetloe baseline so that Svetloe can be used as

an alternate for Wettzell should it be needed.

All sessions are correlated at the Washington Correlator, which is located at USNO and is run

by NEOS.

2. Staff

K. A. Kingham and M. S. Carter are the only staff members of the NEOS Operation Center.

Kingham is responsible for the overall managment and Carter makes the schedules. M. S. Carter

is located at the USNO Flagstaff Station (NOFS).

132 IVS 2007 Annual Report
Correlators

Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn Bonn MPIfR/BKG Correlator

The Bonn Astro/Geo Mark IV Correlator

Alessandra Bertarini, Arno M ̈uskens, Walter Alef

Abstract

The Bonn Mark IV VLBI correlator is operated jointly by the MPIfR and the IGGB in Bonn and

the BKG in Frankfurt. In 2007, e-VLBI transfers became routine for geodetic experiments and, thanks

to that, a new intensive series (INT3) was introduced and is correlated in Bonn. Three Mark 5B units

have been installed and are in regular use for stream correlation. In late December, the first phase of a

Linux cluster dedicated for the software correlator, which will become the long-term future replacement

for the hardware correlator, has been installed.

1. Introduction

The Bonn Mark IV correlator is hosted at the Max-Planck-Institut f ̈ur Radioastronomie

(MPIfR) (http://www.mpifr-bonn.mpg.de/div/vlbicor/) Bonn, Germany. It is operated jointly by

the MPIfR and by Bundesamt f ̈ur Kartographie und Geod ̈asie (BKG) (http://www.bkg.bund.de/)

in cooperation with the Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn (IGGB)

(http://www.gib.geod.uni-bonn.de). It is a major correlator for geodetic observations and MPIfR’s

astronomical projects, for instance those involving millimeter wavelengths and astrometry.

2. Present Status and Capabilities

Figure 1. The left-most rack contains the two correlator crates. The racks second and third from left contain

two station units with two rack-mounted Mark 5A playback units. The right-most rack contains three Mark

5B units and a Mark 5A unit dedicated for e-VLBI.

The Bonn correlator (Fig 1) is one of the four Mark IV VLBI data processors in the world. It

has been operational since 2000. A summary of the Bonn correlator capabilities is presented in

Table 1.

The correlator is controlled by a dedicated Linux workstation and an HP workstation connected

to a Linux file server. Correlation setup, data inspection, fringe-fitting, and data export are done on

a second Linux machine connected to the Linux file server. In 2007, about 700 Gbyte of correlated

IVS 2007 Annual Report 135
Bonn MPIfR/BKG Correlator Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn

Table 1. Correlator Capabilities

Playback Units

Number available: 1 Mark IV tape drive, 8 Mark 5A systems, 3 Mark 5B systems (interchangeable)

Tape types: Thick, thin

Playback speeds: 80 ips, 160 ips (thin tapes); 135 ips, 270 ips (thick tapes)

up to 1024 Mbit/s (Mark 5A)

Formats: Mark III/Mark IV/VLBA (Mark IV/VLBA w/wo barrel roll, data demod.)

Sampling: One bit; two bit

Fan-out: 1:1 1:2 1:4

Fan-in: Not supported

No. channels: ≤ 16 USB and/or LSB

Bandwidth/channel: (2, 4, 8, 16) MHz

Signal: Mono, dual frequency; dual polarization

Modes: 128-16-1 128-16-2 128-8-1

128-8-2 128-4-1 128-4-2

128-2-2 256-16-1 256-16-2

256-8-1 256-8-2 256-4-2

512-16-2 512-8-2

1024-16-2

Correlation

Geometric Model: CALC 8

Number of boards: 16

Phase cal: Two tones (Mark 5A/tape), 16 tones (Mark 5B) extraction at selectable frequencies

Pre-average times: 0.2 s to 5 s

Lags per channel: 32 minimum, 2048 maximum; 1024 tested and used

Maximum output: 10 stations: 45 baselines, 16 channels, 32 lags with

autocorrelation function (ACF) parallel-hand polarizations only

8 stations: 28 baselines, 16 channels, 32 lags with ACF full pol.

Fringe-fit: Off-line FOURFIT

Export: Database, MK4IN to AIPS

data were generated. The total disk space available for data handling at the correlator is more

than 10 Tbyte. Data security is guaranteed by using a file system with redundancy (RAID level

5) and by daily back-up of the data on a PC disk.

3. Staff

The people in the geodetic group at the Bonn correlator are:

Arno M ̈uskens: group leader. Scheduling of T2, OHIG, EURO, INT3, and e-VLBI supervisor.

Simone Bernhart: experiment setup and evaluation of correlated data and media shipping.

(successor of A. H ̈ofer)

136 IVS 2007 Annual Report
Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn Bonn MPIfR/BKG Correlator

Alessandra Bertarini: experiment setup and evaluation of correlated data, software correlator development, e-VLBI commissioning tests and media shipping. Digital baseband converter

(DBBC) testing. PhD student at IGGB since early 2007 to reduce the effect of polarization leakage

on geodetic measurables.

Christian Dulfer: e-VLBI development and operations.

Bertalan Feher: setup and trial correlation of INT3.

Fr ́ed ́eric Jaron: e-VLBI support, software support and Web page maintainance.

Four student operators for night shifts and weekends.

The people in the astronomy group of MPIfR at the Bonn correlator, who support IVS correlation,

are:

Walter Alef: head of the VLBI technical department, correlator software maintenance and

upgrades, computer system administration and friend of the correlator.

David Graham: technical development, consultant, software correlator development and

DBBC development and testing.

Alan Roy: deputy group leader, water vapor radiometer (WVR), technical assistance, FPGA

firmware for DBBC for linear to circular polarization conversion.

Heinz Fuchs: correlator operator, responsible for the correlator operator schedule, daily

operations and media shipping.

Hermann Sturm: correlator operator, correlator support software, media shipping and Web

page development.

Michael Wunderlich: engineer maintaining correlator, playback drives, Mark 5 and development of the DBBC.

Rolf M ̈artens: technician maintaining correlator hardware, playback drives and Mark 5 playbacks.

One student operator for night shifts and weekends and help with VLBI data export.

4. Status

Experiment Status: in 2007 the Bonn group correlated 48 R1, five EURO, one T2, three

OHIG, 18 intensive, one R&D and about 30 astronomical projects.

e-VLBI: near-real-time e-VLBI transfers from Tsukuba, Onsala, Mets ̈ahovi, Ny- ̊Alesund,

Wettzell, and Kashima have become regular at the correlator. This reduced the time between

observation and correlation since no shipment is required. The data rates achieved ranged from

100 Mb/s with Ny- ̊Alesund (limited by radio link) to 400 Mb/s with peak up to 800 Mb/s. The

transfers are done using the UDP-based Tsunami protocol.

INT3: a third intensive series was introduced in mid-2007 and is scheduled and correlated

in Bonn. Thanks to near-real-time e-VLBI transfer, the turnaround between observation and

database submission to the analysis center is about seven hours.

Mark 5B: three Mark 5B units are installed at Bonn and are in regular use since Westford,

Badary and Parkes antennas are equipped with Mark 5B.

Correlator Status: during 2007 the correlator control software has been partly ported from

HP to Linux by the Haystack group. Bonn correlator installed the Linux version of the components

that have been released at an early stage. Six tape drives were decommissioned at the end of 2007

to make space for the software correlator cluster, so the number of usable tape drives is now

reduced to one unit.

IVS 2007 Annual Report 137
Bonn MPIfR/BKG Correlator Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn

Software Correlator: Validation tests of the DiFX software correlator are being conducted

with the support of the Australian group at Melbourne and Perth. First results are very promising

and a small publication is being prepared. A new Linux cluster (Fig: 2) was installed in late

December.

2 nodes for user interaction

1 service node

12 1 GBit inputs for Mark 5 units

21 nodes

8 cores per node

1 I/O node with 20 TB of disk space

20 Gbps InfiniBand interconnections

Figure 2. Scheme of the Linux cluster. The left rack contains top to bottom: part of the nodes, the service

node (with keyboard and monitor), the 20 TB disk RAID, the switches and the panel control. The right

rack contains top to bottom: part of the nodes, empty slots for future nodes an the panel control.

DBBC: the Bonn group is involved in the development of a DBBC for the European VLBI

Network (EVN). This unit is designed as a full replacement for the existing analogue BBCs. Version

1 is in production; the first unit was delivered to Wettzell in November 2007. Two more units have

been integrated and tested in December 2007.

5. Outlook for 2008

Correlator: the tape drive will be maintained in 2008 until the last session with tapes has

been correlated. There will be a gradual changeover to Mark 5B, which will further simplify the

correlation process since the station units will no longer be needed.

Software Correlator: the software correlator will be installed on the new Linux cluster and

first astronomical correlation is awaited by the end of January 2008. The Mark IV hardware

correlator and the new software correlator will coexist for some time.

e-VLBI: stream correlation using e-VLBI transfer will continue and e-VLBI tests with other

antennas are envisaged. A K-band experiment will be transferred via e-VLBI from Australia to

Bonn and copied directly to Mark 5B disks. The net protocol to be used for this transfer is still

under discussion.

Personnel Changes: a new post-doc will dedicate 50% of her/his time for the future development for the software correlator.

DBBC: version 2 is under developement to provide broader bandwidth by using a new

analogue-to-digital converter (ADC) and more powerful FPGA cores. This will lower costs by

implementing four BBCs on a single FPGA. The ADC card prototype is ready for testing. The

new card, the FiLa-10G board, provides outputs on optical fiber and testing will begin in the first

half of 2008.

138 IVS 2007 Annual Report
MIT Haystack Observatory Haystack Correlator

Haystack Observatory VLBI Correlator

Mike Titus, Roger Cappallo, Brian Corey, Kevin Dudevoir, Arthur Niell, Alan Whitney

Abstract

This report summarizes the activities of the Haystack Correlator during 2007. Linux correlator runtime software was developed and migrated to Bonn. Testing of new observing modes and equipment,

primarily Digital Back Ends (DBE), was conducted. Mark 5B capability was migrated to Bonn and

Washington, and Mark 5A/B development continues. One real-time e-VLBI test was conducted, and

real-time e-VLBI capability was restored. Non-real-time transfers continue, and that software and

capability were installed at Bonn. Investigation of 1 Gb/sec EOP results were conducted. Engineering

support of other correlators continues.

Figure 1. Partial view of the Haystack Mark IV correlator, showing 2 racks containing three Mark 5A

correlator playback units, four Mark 5B DOM correlator playback units with associated correlator interface

board units, and a laptop monitor.

1. Introduction

The Mark IV VLBI correlator of the MIT Haystack Observatory, located in Westford, Massachusetts, is supported by the NASA Space Geodesy Program and by the National Science Foundation. The available correlator time is dedicated mainly to the pursuits of the IVS, with a small

portion of time allocated to processing radio astronomy observations for the Ultra High Sensitivity

IVS 2007 Annual Report 139
Haystack Correlator MIT Haystack Observatory

VLBI (u-VLBI) project. The Haystack Correlator serves as a development system for testing new

correlation modes, for e-VLBI, for hardware improvements such as the Mark 5B system, and for

diagnosing correlator problems encountered at Haystack or at one of the identical correlators at

the U.S. Naval Observatory and the Max Planck Institute for Radioastronomy. This flexibility

is made possible by the presence on-site of the team that designed the correlator hardware and

software. Additionally, some production correlator time is dedicated to processing geodetic VLBI

observations for the IVS.

2. Summary of Activities

2.1. Linux Correlator Run-time Software Conversion

This year many run-time programs were migrated to the more contemporary Linux O/S platform Red Hat Enterprise 4. That architecture was installed and is in use at the Bonn correlator.

Washington is expected to upgrade roughly at the time of this writing also. Programs converted

include the messaging system, opera, and conductor. Considerable performance improvements

have been obtained with this conversion at both Haystack and Bonn.

2.2. New Observing Equipment and Methods Testing

Many test experiments related to the application of Digital Back Ends to future observing

methods were conducted. These experiments are a part of the VLBI2010 project and a highsensitivity astronomy project called u-VLBI whose goals include mm-wavelength observations of

the galactic center. In particular, the experiments related to VLBI2010 involve the use of the

Westford and GGAO antennas as test beds for a new very wide band receiver, and a specially

devised observing mode which combines the outputs from two DBE IFs onto one VSI cable, in

support of dual polarization observations.

2.3. Mark 5A/5B Recording System Related Projects

Installation of Mark 5B capability was completed at both the Bonn and Washington correlators

this year. Testing of Mark 5A and 5B software on the correlator continues. One effort is to correct

bad disk-handling limitations on Conduant’s SDK 7 version of their software. These limitations

have become an impediment to upgrading field stations to later versions of the Mark 5A software.

This problem seems close to resolution. Another effort is to add e-VLBI capabilities to the Mark

5B system. This effort is progressing well and should be implemented on the Haystack correlator

soon. Help enabling Mark 5B capabilities at the JIVE correlator is a part of this effort.

2.4. e-VLBI

One real-time e-VLBI test was conducted on the Haystack correlator this year, involving one

VLA antenna and the Westford antenna. This was a proof-of-concept demonstration for NRAO.

e-VLBI efforts have been curtailed for more than a year at the Haystack correlator due to the

removal of our high speed link by Lincoln Laboratory. This link was restored at a 10Gbps data

rate late in 2007 so resumed testing is planned. Non-real-time transfers have continued through

this period, and the software which facilitates this process was installed and is now in use at Bonn,

140 IVS 2007 Annual Report
MIT Haystack Observatory Haystack Correlator

where transfers of data destined for their correlator are conducted on a regular basis. Thirtytwo experiments from four stations were transferred to Haystack this year. These non-real-time

transfers included data from Kashima and Tsukuba, Japan and Syowa, Antarctica.

2.5. Other Projects

Investigations of poor EOP results from 1 Gb/sec geodetic R&D experiments became a priority

this year after a report by Leonid Petrov. Those investigations are continuing. General support of

the other correlators continues, with some examples being repair and testing of Bonn input boards,

loan of a crate control computer to Bonn to replace a failed unit, and much support for software

issues. Many software issues were related to the Linux conversion and installation of Mark 5Bs at

both correlators, but there were other support issues not related to these two major upgrades as

well.

3. Experiments Correlated

In 2007, thirty-one geodetic-VLBI experiments were processed at the Haystack correlator,

consisting of 9 R&Ds, 3 T2s, and 19 test experiments. The test experiments cover a wide assortment

of projects, some of which were touched on in the summary above. There was also a large number

of smaller tests not included in the above count because they were too small to warrant individual

experiment numbers.

4. Current/Future Hardware and Capabilities

Currently, functional hardware installed on the system includes 2 tape units, 7 Mark 5A units,

7 station units, 3 Mark 5B units (DOMs) with their associated correlator interface boards (CIBs),

16 operational correlator boards, 2 crates, and miscellaneous other support hardware. Changes in

the above described matrix compared to last year are the addition of one Mark 5B unit (a USNO

purchased unit currently borrowed for testing), and the reduction of one functional tape unit due

to cannibalization of hardware from the third previously functioning unit. We have the capacity

to process all baselines for 10 stations simultaneously in the standard geodetic modes, provided

the aggregate recordings match the above hardware matrix. In 2008 expansion of the Mark 5B

units may allow for the retirement of Station Units and an increase in available playback units.

5. Staff

Staff who participated in aspects of Mark IV, Mark 5, and e-VLBI development and operations

include:

5.1. Software Development Team

• John Ball - (part time) - Mark 5A/5B; e-VLBI

• Roger Cappallo - real-time correlator software and troubleshooting; system integration; post

processing; Mark 5B; Linux conversion; e-VLBI

• Kevin Dudevoir - correlation; maintenance/support; Mark 5A/5B/5C; e-VLBI; Linux conIVS 2007 Annual Report 141
Haystack Correlator MIT Haystack Observatory

version

• Chester Ruszczyk - e-VLBI; Mark 5C

• Jason SooHoo - e-VLBI; Mark 5C

• Alan Whitney - system architecture; Mark 5A/5B/5C; e-VLBI

5.2. Operations Team

• Peter Bolis - correlator maintenance

• Brian Corey - experiment correlation oversight; station evaluation; technique development

• Dave Fields - playback drive maintenance; Mark 5 installation and maintenance; general

technical support

• 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

& hardware testing

• Ken Wilson - correlator maintenance; playback drive maintenance; general technical support

6. Conclusion/Outlook

Further migration of run-time programs to the Linux platform is expected in the coming year.

Expansion of Mark 5B units at all correlators will continue as more field stations convert to Mark

5B. Mark 5C testing should begin. For information regarding the Mark 5C recording system,

please refer to the “Haystack Observatory Technology Development Center” report. e-VLBI testing

should increase this year with the return of the high speed link. Further testing of Digital Back

Ends will continue, with the intent of transforming standard observing techniques to higher data

rates in the coming years. This is an exciting time at the Haystack correlator, with many new

systems coming on-line, promising vast improvements in all aspects of observing.

142 IVS 2007 Annual Report
IAA RAS IAA Correlator Center

IAA Correlator Center

Igor Surkis, Andrey Bogdanov, Artemy Fateev, Alexey Melnikov, Violet Shantyr,

Vladimir Zimovsky

Abstract

The 12-board correlator MicroPARSEC equipped with S2-PT terminals was completed in 2007.

This correlator is used for processing up to 3-station observations. The new correlator ARC for 6-station

VLBI observations processing is under development. The VLBI data of the 3-station observations of

the Russian national network Quasar was processed using MicroPARSEC correlator.

1. Introduction

The IAA Correlator Center is located 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. Summary of Activities

2.1. MicroPARSEC Correlator Development

In 2007 the 12-board correlator MicroPARSEC was finished (Figure 1). It is capable of processing simultaneously up to 24 frequency channels to a maximum of 32MHz clock frequency and 2-bit

sampling. The correlator is designed to process 2- or 3-station VLBI observations of 16 frequency

channels from each station. If handling 3-station experiments, then 3 baselines of 8 frequency

channels each are processed simultaneously.

At present the correlator is used for processing VLBI observations for astrometry. As a result,

the correlator produces accurate geometric delays stored in NGS files.

Special PCI-standard boards called “MicroPARSEC units” are the main component of the

MicroPARSEC correlator. Each unit is designed based on the Altera FPGA technology and

contains two XF correlation devices. These units are placed into a special industrial computer

(Figure 2).

Currently the correlator is equipped with two S2 playback terminals. In 2008 we are planning

to equip it with Mark 5B terminals.

2.2. ARC Correlator Development

A new correlator ARC (Astrometric Radiointerferometric Correlator) development was started

in 2007. This correlator will be able to process VLBI signals from 6 station (15 baselines) with 16

frequency channels each simultaneously. The correlator will have 2-bit sampled VSI-H signals at

32MHz maximum clock on its input. The maximum data rate of each station would be 1 Gbit per

second. We are planning to equip this correlator with Mark 5B terminals.

The main processing device of ARC is BMC (Basic Module of Correlator), which is very similar

to the MicroPARSEC unit (Figure 3). It is designed with FPGA technology in PCI board standard.

The XF correlation algorithm is applied. All mathematical algorithms are FPGA’s code.

IVS 2007 Annual Report 143
IAA Correlator Center IAA RAS

Figure 1. 12-board MicroPARSEC correlator.

Figure 2. Industrial computer chassis with 12 MicroPARSEC units.

In comparison with MicroPARSEC unit, BMC has a larger size. It is Compact PCI 6U device.

Also BMC has a greater number of correlation devices—16 instead of 2 in MicroPARSEC unit.

Each device represents a single-baseline, single-channel XF correlator for calculating 64 complex

delays and picking out calibration signals. BMCs are inserted into the Compact PCI 6U crates.

The correlator includes 15 BMCs and 6 Mark 5B terminals. SDSS (Signals Distribution

and Synchronization System) provides Mark 5B with synchronization signals (DPSCLOCK and

DPS1PPS) and transmits VLBI data from Mark 5B to BMC (Figure 4). SDSS transfers data

streams of each station to 5 BMCs.

BMCs carry out all hardware data processing. Each BMC receives data streams of 2 stations

and processes 16 frequency channels per baseline.

The correlator hardware control software is distributed over 4 Compact PCI 6U crates with

144 IVS 2007 Annual Report
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Figure 3. ARC BMC unit (left) and MicroPARSEC unit (right).

Figure 4. ARC correlator.

BMCs and a personal computer from where management is being carried out. Mark 5B terminal

control, crates coordination, and data transfer are realized through the local correlator network.

At the present time the pilot batch of the BMCs have been produced. The correlator prototype

construction has been started. We are planing to complete and test the full scale correlator in

2009.

3. Experiments Done

The regular national VLBI observations with the 3-station Quasar VLBI network were continued in 2007. Observational data were processed using the 4-board MicroPARSEC correlator

(before February 2007) and 12-board MicroPARSEC correlator (since February 2007). All the

IVS 2007 Annual Report 145
IAA Correlator Center IAA RAS

processed VLBI observations were 14 24-hour, 3-baseline sessions and 24 8-hour, single-baseline

sessions.

The obtained group and ionospheric delay accuracy varies from 50 to 100 picoseconds.

4. Staff

• Andrey Bogdanov — software developer

• Artemy Fateev — software developer

• Alexey Melnikov — software developer, scheduler

• Violet Shantyr — software developer, post processing

• Igor Surkis — leading investigator, system integrator, software developer

• Vladimir Zimovsky — hardware developer, system integrator, correlator operator

146 IVS 2007 Annual Report
National Institute of Information and Communications Technology VLBI Correlators at Kashima

VLBI Correlators at Kashima

Mamoru Sekido, Tetsuro Kondo, Moritaka Kimura, Yasuhiro Koyama

Abstract

The software correlator systems developed at Kashima Space Research Center are used for data

processing of R&D VLBI experiments. In 2007 the correlation tasks processed were an e-VLBI project

for rapid UT1 measurements, the CARAVAN2400 project for reference baseline determination with

small diameter antennas, and a project for comparison of time standards with VLBI. An automatic

data processing scheme was newly introduced and it has drastically reduced the latency of UT1 determination. The rapid UT1 measurement with e-VLBI was demonstrated at the JGN2 symposium

2008. The automated correlation processing scheme also works efficiently in the other projects. The

implementation of the high speed correlation software package GICO3 into the correlation system for

the VERA project is in progress under contract with NAOJ.

1. General Information

The VLBI group of Kashima Space Research Center (KSRC) of National Institute of Information and Communications Technology (NICT) has been developing software correlators and the

disk-based data acquisition system called K5. The software correlator system works on a cluster

of personal computers (PCs), and it has the capacity for automation and for modification of the

correlation configuration for specific data processing.

2. Component Description

NICT has developed two kinds of data acquisition systems (DAS): K5/VSI and K5/VSSP

[1]. Software correlator adaptations have been developed for each of them. To clearly distinguish

the two software correlator packages, Table 1 summarizes their differences. Mainly the ‘cor &

fx cor’ system has been used for geodetic data processing such as UT1 measurements and the

CARAVAN2400 project. In the following, ‘K5 software correlator’ means ‘cor & fx cor’ system,

except when clearly stated otherwise (e.g., K5/VSI correlator).

Table 1. Two kinds of K5 software correlators developed at KSRC.

Name of Corresponding Number of Processing Main

Module DAS System Data Channel Speed Developer Applications

cor & fx cor K5/VSSP, K5/VSSP32 4 x 4ch Medium T. Kondo Geodesy

UT1

GICO3 K5/VSI 1ch (∼ N) Fast M. Kimura Astronomy

VERA Project

2.1. Software Correlator for K5/VSSP (‘Cor & Fx cor’)

The K5 software correlator system has been developed by T. Kondo [2] with the aim of

geodetic VLBI data processing. It has been originally dedicated for processing the data of

K5/VSSP(VSSP32) [3], which is a disk-based VLBI data recording system developed at NICT.

IVS 2007 Annual Report 147
VLBI Correlators at Kashima National Institute of Information and Communications Technology

The K5 software correlation package includes the format converter between K5/VSSP and Mark 5

system. Thus it can be used for correlation processing of Mark 5 data via data format conversion.

Now the K5 software correlation system has been exported to JIVE under a license agreement

and it has been routinely used for fringe detection for VLBI observations of the European VLBI

Network.

Figure 1. A view of the observation room of the

Kashima 34m antenna. The K5 system in this room is

used both for observation and correlation processing.

Some perl script package wrapping for the

correlator core software (‘cor & fx cor’) was

developed in 2007. They provide a communication function to the correlator core which

enables an automatic correlation processing

with distributed computation on a PC cluster. This capability contributed to the improvement of the latency of the ultra-rapid

UT1 measurement. The rapid UT1 measurement has been conducted in a collaboration

among NICT, Geographical Survey Institute

(GSI) Japan, Onsala Space Observatory (Sweden), and Mets ̈ahovi Radio Observatory (Finland). UT1 estimation has become available

with 30 minutes of latency by using multiple

technologies such as high speed network, data

transport protocol ‘tsunami’, disk-based data

recording systems K5/VSSP32 and Mark 5 [4], and PC interface VSI-B [5]. One target of the

rapid-UT1 measurement project is the evaluation of the operational stability of pseudo-realtime

e-VLBI as well as the stability of the solution. The ‘tsunami’ protocol [6] made the real-time

transfer of observed VLBI data in Mark 5 format possible over intercontinental distances (Onsala, Mets ̈ahovi to Kashima,Tsukuba). Then data format conversion from Mark 5 to K5 and

cross correlation processing are performed. For utilizing this automated processing, only the clock

parameters need to be fixed before the experiment.

A VLBI database system based on NetCDF1 has been developed by T. Hobiger (MK3TOOLS)

[7, 8]. After the correlation processing, the MK3TOOLS have been used for the creation of Mark

III databases for the analysis with the CALC/SOLVE system. The NetCDF database file is used

as intermediate database to generate a Mark III database. Since the MK3TOOLS have a function

to generate NGS card format as well, this is used for the analysis with OCCAM analysis system.

Automatic analysis procedure for UT1 estimate is being developed by T. Hobiger by using the

MK3TOOLS, NGS databases, and the OCCAM software.

Besides UT1 observations, the correlation system has been used for the CARAVAN2400

project [1], a project of time standards comparison with VLBI [1], and some fringe test experiments for supporting VLBI stations of JAXA/ISAS.

2.2. GICO3 Correlator with K5/VSI

GICO3 is a high speed correlation software developed by M. Kimura for the K5/VSI system.

Under a contract with National Astronomical Observatory of Japan (NAOJ), a correlation pro1

http://www.unidata.ucar.edu/software/netcdf/

148 IVS 2007 Annual Report
National Institute of Information and Communications Technology VLBI Correlators at Kashima

Table 2. e-VLBI sessions for rapid UT1 measurement performed since April 2007. Station codes are as

follows, ’Ks’:Kashima34, ’Ts’:Tsukuba 32, ’On’:Onsala, ’Mh’:Mets ̈ahovi, and ’Wz’:Wettzell. The effective

band width for the experiments from 3rd April to 4th June are 140.2MHz and 33.1 MHz for X and S-band,

respectively. And those for experiments from 14 and 15 July are respectively 280.4 MHz and 48.8 MHz

for X and S-band. The experiments on 14 and 15 July were performed by add on to the INT-2 sessions of

Tsukuba-Wettzell baseline.

Date Baseline Data rate UT1-UTC UT1-c04 Error Latency

2007 (Mbps) (ms) (μ sec.) (μ sec.)

03 April Ks – On 256 -69.6044 -38.5 8 –

23 April Ks – On 128 -98.4422 15.0 41 1 h 55 min.

02 May Ks – On 128 -110.0189 -30.4 16 –

18 May Ks – Mh 128 -130.5832 67.5 98 2 h 38 min.

30 May Ks – On 128 -143.2703 -14.7 9 28 min.

31 May Ks – On 128 -143.7011 -83.5 8 –

04 June Ks – On 256 -144.6447 13.1 6 31 min.

14 July Ks-On, Ks-Wz 256 -162.0879 6.2 6 –

Ks – On -162.1017 -7.6 10

Ks – Wz -162.0715 22.6 8

Ts – Wz, On-Ts -162.0674 26.7 8

On – Ts -162.0725 21.6 7

Ts – Wz -162.0585 35.6 5

Ts – Wz(INT2) -162.0974 -3.3 7

15 July Ks – On 256 -162.0186 -30.7 6 –

Ts – Wz(INT2) -162.0017 -13.8 8

cessing system using the software correlator is being developed for the VERA project [9]. The

system is designed for processing 10 baselines of cross correlation and 5 stations autocorrelation,

simultaneously [10]. The data rate is 1 Gbps for each station. A picture of the correlation system

composed of 5 PCs is displayed in Table 3

3. Staff

• Tetsuro Kondo is working for development and maintenance of software correlator package

(cor & fx cor). Data format converter between Mark 5 and K5 is included in the package.

He also is in charge of the development of the PC-based VLBI sampler K5/VSSP32 [3].

• Yasuhiro Koyama is project leader of the “Space-Time Application Project” and is in charge

of overall activity in our group.

• Mamoru Sekido is in charge of the e-VLBI activity.

• Moritaka Kimura is working on the development of a high speed Giga bit software correlator.

He is in charge of the development of software correlators for the VERA project.

• Thomas Hobiger is developing a new VLBI database system using NetCDF. He also is active

in research of atmospheric path delay calibration with ray tracing technique.

• Masanori Tsutsumi is working as system engineer for maintenance of computers.

IVS 2007 Annual Report 149
VLBI Correlators at Kashima National Institute of Information and Communications Technology

Table 3. Picture and Specification of Software Correlator for VERA Project

Specification parameters of the Software Correlator

Stations 5

Baselines 10

Processing Rate 512 - 1024 Mbps/station

Lags Number 64 - 64000 points

Output 10 cross and 5 auto correlations

Output rate 1 - 100Hz

Output format CODA, FITS

References

[1] T. Kondo, Y. Koyama, R. Ichikawa, M. Sekido: Technology Development Center at NICT, International

VLBI Service for Geodesy and Astrometry 2007 Annual Report, this issue, 2008.

[2] Y. Koyama, T. Kondo, H. Osaki, K. Takashima, K. Sorai, H. Takaba, K. Fujisawa: Evaluation of the

K5 system in geodetic VLBI experiments, Technical Development Center News CRL, No.23, 26-30,

2003.

[3] T. Kondo,Y. Koyama, H. Takeuchi, M. Kimura: Development of a New VLBI Sampler Unit

(K5/VSSP32) Equipped with a USB 2.0 Interface, IVS 2006 General Meeting Proceedings, edited

by Dirk Behrend and Karen Baver, NASA/CP-2006-214140, p.195-199, 2006

[4] Whitney, A.R.: The Mark 5B VLBI Data System, IVS 2004 General Meeting Proceedings (eds.

Nancy R. Vandenberg & Karen D. Baver), NASA/CP-2004-212255, 177–181, 2004.

[5] Ritakari, J., and A. Mujunen: Gbit/s VLBI and e-VLBI with Off-The-Shelf Components, IVS 2004

General Meeting Proceedings (eds. Nancy R. Vandenberg & Karen D. Baver), NASA/CP-2004-

212255, 182–185, 2004.

[6] Meiss, M.R.: “Tsunami: A High-Speed Rate-Controlled Protocol for File Transfer”,

http://steinbeck.ucs.indiana.edu/ mmeiss/papers/tsunami.pdf, 2004.

[7] T. Hobiger, Y. Koyama, and T. Kondo: MK3TOOLS & NetCDF - storing VLBI data in a machine independent array oriented data format ,http://mars.hg.tuwien.ac.at/ evga/proceedings/P03 Hobiger.pdf

[8] T. Hobiger, R. Ichikawa, M. Sekido, H. Takiguchi, T. Kondo, Y. Koyama: Analysis Center at National

Institute of Information and Communications Technology, International VLBI Service for Geodesy and

Astrometry 2007 Annual Report, this issue, 2008.

[9] M. Honma et al.: Multi-Epoch VERA Observations of H2O Masers in OH 43.9 – 0.1, Publ. Astron.

Soc. Japan Vol 57 pp. 595-603, 2005

[10] M. Kimura: Development of the software correlator for the VERA system, Technical Development

Center News NICT, No.26, 26-27, 2005.

150 IVS 2007 Annual Report
Geographical Survey Institute, Japan Tsukuba VLBI Correlator

Tsukuba VLBI Correlator

Hiromi Shigematsu, Etsuro Iwata, Morito Machida, Kozin Wada

Abstract

This is a report of the activities at the Tsukuba VLBI Correlator in 2007.

1. General Information

The Tsukuba VLBI Correlator is situated at the Geographical Survey Institute (GSI) in

Tsukuba, Ibaraki Pref., Japan. It is a part of VLBI components operated by GSI, together with

the Tsukuba 32-m VLBI station (TSUKUB32). There are two K5/VSSP correlator units. Intensive sessions (IVS-INT2), performed on Saturday and Sunday on the TSUKUB32–WETTZELL

baseline for monitoring UT1-UTC, have been correlated at the Tsukuba VLBI Correlator. Processing of JADE series (geodetic sessions with domestic VLBI network of GSI, run for 24 hours)

is also a major task for the Tsukuba VLBI Correlator.

2. Component Description

Both the K5/VSSP correlator units “system 1” and “system 2” have been in operational use.

A component description for both units is presented in Table 1.

Removable disk cartridges from the stations are connected to a data server in an external

mounting mode. Each data server can share a couple of the disk cartridges at once through a

drive unit. The data servers can perform distributed computing as well as function as correlation

servers. File handling and multi-task control is assumed by the management computer. There

is no need to assemble a K5/VSSP correlator unit from individual components; an off-the-shelf

computer provides sufficient hardware to support a K5/VSSP correlator unit.

Software correlation processing on the K5/VSSP correlation unit is based on the IP-VLBI

technology. It has been developed at NICT (National Institute of Information and Communications Technology, Japan). The most essential elements are four kernel programs: “apri calc”,

“cor”, “sdelay” in correlation package “ipvlbi20080110”, and “komb” in “komb20071214”. These

K5/VSSP packages are licensed by NICT. Based on an agreement about research cooperation between GSI and NICT, the Tsukuba VLBI Correlator is allowed to take advantage of the products.

“apri calc” calculates a priori delay&rate for each scan per single baseline. “cor” executes software

correlation. “sdelay” makes coarse fringes directly from correlator output. “komb” is a bandwidth

synthesis program to obtain multi-band delays. K5/VSSP also has a conversion program; it can

convert K5 to Mark 5 format and vice versa.

The kernel programs have the capability of processing only one single baseline scan. To meet

the demands for processing many scans for multi-baselines, a simple way of distributed computing

is brought into the unit. Once there is an uncorrelated data set, the task for it is distributed

to any vacant correlation server. The auxiliary application software “PARNASSUS” handles the

detailed control of processing multiple tasks. The acronym “PARNASSUS” stands for Processing

Application in Reference to NICT’s Advanced Set of Softwares Usuable for Synchronization. The

latest version PARNASSUS 1.3, developed at GSI and released March 2006, is installed in the

management computer. PARNASSUS serves the operator as a tool, providing a graphical user

IVS 2007 Annual Report 151
Tsukuba VLBI Correlator Geographical Survey Institute, Japan

Table 1. Component description of the Tsukuba correlator

system 1 system 2

management computer 1 1

(CPU) Intel Pentium 4, 3.0GHz Intel Pentium 4, 3.0GHz

data servers 23 8

(CPU) Intel Pentium 4, 3.0GHz Intel Pentium 4, 3.4GHz

correlation servers 16 (rackmount type computer) 8 (rackmount type computer)

(CPU) Intel Xeon 3.06GHz (dual CPUs) Intel Xeon 3.4GHz (dual CPUs)

format K5/VSSP

media type SATA disk cartridge

kernel program package ipvlbi20080110, komb20071214

aid application PARNASSUS 1.3

OS Linux

operation JADE IVS-INT2

installation April 2005 August 2006

interface and facilitating multi-task control. CALC/SOLVE developed by NASA/GSFC is installed

on an HP workstation to produce primary solutions.

3. Staff

A list of the staff at the Tsukuba VLBI Correlator in 2007 is given below. Staff in the observation domain are listed in the report of the Tsukuba 32-m VLBI station in the Network Stations

section of this volume. K. Takashima, long time VLBI group member of GSI and the operations

manager of the Tsukuba VLBI Correlator for the last four years, has left for a new career in April.

In his stead, K. Wada took over the responsibility of GSI’s representative member for Observing

Program Committee. Routine operations were mainly performed under contract with Advanced

Engineering Services Co., Ltd (AES) over 200 days in the 2007 fiscal year (April 2007 through

March 2008). AES was asked for 20 additional days of routine operations which were funded by

National Astronomical Observatory of Japan (NAOJ). AES was also asked for 13 additional days

of routine operations which were funded by Japan Aerospace Exploration Agency (JAXA).

• S. Matsuzaka : Supervisor, Head of Space Geodesy Division (GSI)

• K. Wada : Operations manager (GSI)

• E. Iwata : technical staff (GSI), network expert, system development and consultant

• H. Shigematsu : technical staff (GSI), correlation chief, media library and shipping

• M. Machida : technical staff (GSI)

• K. Nozawa : main operator in routine correlation processing (Advanced Engineering Services

Co., Ltd)

• K. Takano : sub-operator in routine correlation processing, (Advanced Engineering Services

Co., Ltd)

152 IVS 2007 Annual Report
Geographical Survey Institute, Japan Tsukuba VLBI Correlator

4. Current Status and Activities

During 2007, 95 Intensive sessions (IVS-INT2) on TSUKUB32-WETTZELL single baseline for

UT1, three Intensive sessions (IVS-INT2) on KASHIM34-WETTZELL single baseline for UT1, and

12 24-hour geodetic sessions of domestic network (JADE series) were processed at the Tsukuba

VLBI Correlator.

One geodetic session for 24-hour (U07173 session) was processed also at the Tsukuba VLBI

Correlator. The U07173 session, conducted under GSI’s initiative, aimed at the improvement of

both the USUDA64 and YAMAGUCH site positions. USUDA64, 64 m in diameter, belongs to

and is funded by JAXA as a tracking antenna for deep space missions. YAMAGUCH, 32 m in

diameter, belongs to NAOJ’s resources, and is operated by Yamaguchi University as a contribution to observational research in astrophysics under cooperative relationship between NAOJ and

Yamaguchi University. Processing of U07173 was funded by JAXA.

Some baselines of the four “ultra-rapid dUT1 e-VLBI” sessions were processed at the Tsukuba

VLBI Correlator in the form of test experiments.

Processing of JADE series is usually done with “system 1”, while “system 2” has continued

operations mainly for processing Intensive sessions. One of our plans came due to add some more

servers to “system 2” as expansion. Eight rack-mount-type Linux computers were provided for

this work.

Many correlation tasks have been routinely loaded on “system 1” and “system 2”. Now two

years have passed since the installation of “system 1”. Some components went down. This may

lead to an overload on the remaining group of machines. The task information in the access control

list is generally sorted by classification according to scan number first and then to baseline. There

sometimes occured an interruption of the computing process in the middle of a correlation. The

cause was likely a full disk drive, which was accessed frequently for reading data files, eventually

resulting in an NFS (Network File System) service stop.

5. Plan for 2008

• It is planned to continue to process the TSUKUB32/WETTZELL Intensive sessions (IVSINT2) with the K5/VSSP system. The sessions are to be performed on both Saturday and

Sunday with K5/VSSP (TSUKUB32) and Mark 5 (WETTZELL) systems. The Tsukuba

VLBI Correlator is also expected to be responsible for processing 12 geodetic sessions (JADE)

of the domestic VLBI network of GSI.

• We will add some more correlation servers and data servers to the existing K5/VSSP correlation units. At the same time, overloaded servers will be replaced with modern Linux

machines to recover properly the performance of the K5/VSSP correlation units. In addition, the interface devices of the drive units have been gradually damaged through frequent

loading of disk cartridges into the drive slots. The recovery process requires an overhaul of

the drive units for both correlator and station use.

• Discussions for the next version of “PARNASSUS” will continue in the advisory team of VLBI

correlation domain. The current style of distributed computing appears not to be optimized

for obtaining the greatest performance from dual CPUs capacity of correlation server. To

make multi-task processing executable on dual CPUs mode effectively, we plan to upgrade

PARNASSUS by improving the access control to each correlation server. In order to fix the

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Tsukuba VLBI Correlator Geographical Survey Institute, Japan

sudden interruption of the computing process on a machine, the action plan will address

the software and hardware levels. New features will be introduced into PARNASSUS, such

as handling each task information in a random manner and sorting access control first by

baseline and then by scan number in order to avoid frequent access to a specific data server.

The design of interaction among servers will be revised to keep the data processing running.

154 IVS 2007 Annual Report
U. S. Naval Observatory Washington Correlator

Washington Correlator

Kerry A. Kingham, David M. Hall

Abstract

This report summarizes the activities of the Washington Correlator for the year 2007. The Washington Correlator provides up to 80 hours of processing per week, primarily supporting Earth Orientation

and astrometric observations. An additional 40 hours per week of unattended processing is also provided routinely. In 2007 the major programs supported include the IVS-R4, IVS-INT, IVS-R1, APSG,

and CRF (CRF,CRMS,CRDS,CRFS) observing sessions.

1. Introduction

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

experiments. All of the weekly IVS-R4 sessions, all of the daily Intensives, and several IVS-R1

sessions were processed at WACO. The remaining time was spent on terrestrial reference frame

and astrometry sessions. The facility houses a Mark IV Correlator.

Figure 1. The right half of WACO showing 4 Mark 5A units (far right), legacy tape drives, the operator’s

console, Mark 5B (left of console) and the central processor (left).

2. Correlator Operations

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

IVS 2007 Annual Report 155
Washington Correlator U. S. Naval Observatory

average, of extra processing. This has also decreased the time it takes to process an R4 or R1 by

one day.

The correlator staff continues the testing and repair of Mark 5 modules. Not only were failed

disks replaced, but some modules were upgraded by the replacement of small disks with larger

ones.

The Intensive observations from Wettzell continue to be electronically transferred to the Washington area and transported to the correlator. This operation saves 1 to 2 days of shipping time.

A Mark 5B playback unit was added to the correlator complement of Mark 5’s, which now

allows the correlator to process 9 stations (8 Mark 5A and 1 Mark 5B) simultaneously. Six

sessions requiring at least one tape drive were processed in 2007.

Table 1 lists the experiments processed during 2007.

Table 1. Experiments processed during 2007

52 IVS-R4 experiments

19 CRF (Celestial Reference Frame)

2 IVS-R1

2 APSG (Asia Pacific)

232 Intensives

16 Kk-Sv-Wz Intensives

3. Staff

The Washington Correlator is under the management and scientific direction of the Earth

Orientation Department of the U.S. Naval Observatory. USNO personnel continue to be responsible

for overseeing scheduling and processing. During the period covered by this report, a private

contractor, NVI, Inc., supplied a contract manager and correlator operators.

Table 2 lists staff and their duties.

Table 2. Staff

Staff Duties

Dr. Kerry Kingham (USNO) VLBI Correlator Project Scientist

David Hall (USNO) VLBI Correlator Project Manager

Bruce Thornton (NVI) Operations Manager

Harvis Macon (NVI) Lead Correlator Operator

Roxanne Inniss (NVI) Media Librarian

Kenneth Potts (NVI) Correlator Operator

156 IVS 2007 Annual Report
U. S. Naval Observatory Washington Correlator

Figure 2. Roxanne Inniss, Bruce Thornton and Dave Hall keep an eye on processing.

4. Outlook

The Washington Correlator plans to upgrade the Mark 5A playbacks to Mark 5B, in coordination with the installation of Mark 5Bs at the Network Stations, and to upgrade to a new correlator

control computer. It is expected that the number of playbacks available will increase to 11 with

the addition of 2 Mark 5B units before the existing Mark 5A units are converted to Mark 5B.

Plans include bringing a broadband connection to the Correlator in 2008.

IVS 2007 Annual Report 157

Data Centers

Bundesamt f ̈ur Kartographie und Geod ̈asie BKG Data Center

BKG Data Center

Volkmar Thorandt, Reiner Wojdziak

Abstract

This report summarizes the activities and background information of the IVS Data Center for the

year 2007. 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 CDDIS Data

Centers by mirroring the OPAR and the CDDIS file stocks several times per day. The following

sketch shows the principle of mirroring:

Figure 1. 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 of them has at its disposal. The BKG incoming area is

protected and users need to obtain username and password to get access (please contact the Data

Center staff).

An incoming script is watching the incoming area and checking the syntax of the files sent by

IVS components. If it is o.k. 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 Data Center by sending e-mails about its activities. The incoming script is a part of the

technological unit which is responsible for managing the IVS and the Operational Data Center and

to carry out first analysis steps in an automatic manner. All activities are monitored to guarantee

data consistency and to control all analysis steps from data incoming to delivering of analysis

products to IVS.

IVS 2007 Annual Report 161
BKG Data Center Bundesamt f ̈ur Kartographie und Geod ̈asie

Public access to the BKG Data Center is available through FTP and HTTP:

FTP: ftp://ivs.bkg.bund.de/pub/vlbi/

HTTP: http://ivs.bkg.bund.de/vlbi/

Structure of BKG IVS Data Center:

vlbi/ : root directory

ivs-iers/ : VLBI products for IERS

ivs-pilot2000/ : directory for special investigations

ivs-pilot2001/ : directory for special investigations

ivs-pilotbl/ : directory for baseline time series

ivs-pilottro/ : directory for tropospheric time series

ivs-special/ : special CRF investigations

ivscontrol/ : controlfiles for the data center

ivsdata/ : VLBI observation files

ivsdocuments/ : IVS documents

ivsproducts/ : analysis products

(earth orientation, terrestrial and celestial frames,

troposphere, daily sinex files)

2. Technical Equipment

DELL Server (SUSE Linux Enterprise 9.5 operating system)

disk space: 300 GBytes (Raid system)

backup: 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)

162 IVS 2007 Annual Report
NASA Goddard Space Flight Center CDDIS Data Center

CDDIS Data Center Summary for the 2007 IVS Annual Report

Carey Noll

Abstract

This report summarizes activities during the year 2007 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. Introduction

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 raw and analyzed data to facilitate scientific

investigation. The CDDIS archive of GNSS (GPS and GLONASS), laser ranging, VLBI, and

DORIS data is stored on-line for remote access. Information about the system is available via the

Web at the URL http://cddis.gsfc.nasa.gov. The current and future plans for the system’s support

of the IVS are discussed below.

2. System Description

The CDDIS archive of VLBI data and products is accessible to the public via anonymous ftp

access.

2.1. Computer Architecture

The CDDIS is operational on a dedicated server, cddis.gsfc.nasa.gov. The system has over 3.5

Tbytes of on-line magnetic disk storage; over 1 Tbytes are devoted to VLBI activities. A dedicated

DLT tape system is utilized for system backups. The CDDIS is located at NASA GSFC and is

accessible to users 24 hours per day, seven days per week.

2.2. Staffing

Currently, a staff consisting of one NASA civil service employee and two contractor employees

supports all CDDIS activities. (See Table 1 below.)

Table 1. CDDIS Staff

Name Position

Ms. Carey Noll CDDIS Manager

Dr. Maurice Dube Head, CDDIS contractor staff and senior programmer

Ms. Ruth Labelle Programmer

IVS 2007 Annual Report 163
CDDIS Data Center NASA Goddard Space Flight Center

3. Archive Content

The CDDIS has supported GSFC VLBI coordination and analysis activities for the past several

years through an on-line archive of schedule files, experiment logs, and data bases in several formats.

This archive has been expanded for the IVS archiving requirements.

The IVS data center content and structure is shown in Table 2 below. (A figure illustrating

the flow of information, data, and products between the various IVS components was presented in

the CDDIS submission to the 2000 IVS Annual Report.) In brief, an incoming data area has been

established on the CDDIS host computer, cddis.gsfc.nasa.gov. Using specified file names, operation

and analysis centers deposit data files and analyzed results to appropriate directories within this

filesystem. Automated archiving routines, developed by GSFC VLBI staff, peruse the directories

and migrate any new data to the appropriate public disk area. These routines migrate the data

based on the file name to the appropriate directory as described in Table 2. 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 has been 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 f ̈ur Kartographie und Geod ̈asie in Leipzig, and the Observatoire de

Paris.

The public filesystem in Table 2 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 data base and NGS card image formats). A products disk area has

also been 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 2007, over 150 user organizations accessed the CDDIS on a regular basis to retrieve

VLBI related files. These users downloaded over 460K 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. Last year we

procured new computer hardware that will increase the CDDIS on-line disk storage capacity, ensure

system redundancy, and better serve our user community. We hope to be operational on this new

system in the spring of 2008.

164 IVS 2007 Annual Report
NASA Goddard Space Flight Center CDDIS Data Center

Table 2. IVS Data and Product Directory Structure

Directory Description

Data Directories

vlbi/ivsdata/db/yyyy VLBI data base files for year yyyy

vlbi/ivsdata/ngs/yyyy VLBI data files in NGS card image format for year

yyyy

vlbi/ivsdata/aux/yyyy/ssssss Auxillary files for year yyyy and session ssssss; these

files include: log files, wx files, cable files, schedule

files, correlator notes

vlbi/raw Raw VLBI data

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-pilot2000 IVS Analysis Center pilot project (2000)

vlbi/ivs-pilot2001 IVS Analysis Center pilot project (2001)

vlbi/ivs-pilotbl IVS Analysis Center pilot project (baseline)

vlbi/ivs-pilottro IVS Analysis Center pilot project (troposphere)

vlbi/ivs-special IVS special analysis solutions

Other Directories

vlbi/ivscontrol IVS control files (master schedule, etc.)

vlbi/ivsdocuments IVS document files (solution descriptions, etc.)

vlbi/dserver dserver software and incoming files

IVS 2007 Annual Report 165
Italy INAF Data Center Istituto di Radioastronomia–Bologna

Italy INAF Data Center Report

M. Negusini, P. Sarti, S. Montaguti

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. We also report about some changes in the hardware facilities devoted to IVS

activities.

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 have been 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 (for

the time being, we have done this for 1998 and 1999 EUROPE experiments), as if they were

produced by a WVR. These databases are available 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, where Mark 5 Calc/Solve version 10

was installed and all VLBI data analysis migrated. The Internet address of this computer is

sarip.ira.inaf.it. Since 2007 a new server with a storage capacity of 1 TB has been available and,

therefore, all experiments performed in the previous years were downloaded and archived, thus

completing the catalogue. 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/super

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.

166 IVS 2007 Annual Report
Istituto di Radioastronomia–Bologna Italy INAF Data Center

The HP 785/B2600 workstation is still maintained. The Internet address of this computer is

boira3.ira.inaf.it and the databases are stored in different directories and on different disks as well.

The complete list of directories where databases are stored follows:

1 = /data1/mk3/data1

2 = /data1/mk3/data2

4 = /data6/dbase6

6 = /data5/dbase5

5 = /data4/dbase4

7 = /data7/dbase7

8 = /data8/dbase8

9 = /data9/dbase9

The username for accessing the database at the moment is geo. The password can be requested

by sending an e-mail to negusini@ira.inaf.it.

The other workstation still working in Bologna is an HP282 computer with Internet address

hp-j.ira.inaf.it. The databases are stored in the following directories:

7 = /data8/dbase8

8 = /data10/dbase10

The superfiles are stored in different directories:

/data2/super

/data10/super10

/data9/super9

/data8/super8

The list of superfiles is stored in the file /data6/solve files/SUPCAT. The area for data storage

has a capacity of 366 gigabytes with the installation of an external server. The data can be accessed

using the username geo, and the password can be requested by writing to negusini@ira.inaf.it.

IVS 2007 Annual Report 167
Data Center at NICT Kashima Space Research Center, NICT

Data Center at NICT

Yasuhiro Koyama, Mamoru Sekido, Hiroshi Takiguchi

Abstract

The Data Center at 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 with the Key Stone Project VLBI Network were the

primary objects 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. Introduction

In April 2004, the Communications Research Laboratory was integrated with the Telecommunications Advanced Organization of Japan (TAO) to establish the National Institute of Information

and Communications Technology (NICT) as a new institute. The IVS Data Center at NICT

archives and releases the databases and analysis results processed by the Correlation Center and

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 were no additional data for the KSP regular sessions since 2002. In 2006, for example,

five geodetic VLBI sessions were added. The analysis results in SINEX (Solution INdependent

EXchange) file format as well as other formats are available on the WWW server. Database files

generated with the Mark III database file format are available upon request and will be sent to

the users on DDS tape cartridges. 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 Data Center at NICT. In the past, an FTP server was

used to provide data files, but it was decided to terminate the FTP service because of security

risks of maintaining an anonymous FTP server. Instead, the WWW server www3.nict.go.jp was

prepared to place large size data files.

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/w/w114/stsi/database/

e-VLBI Sessions http://www.nict.go.jp/w/w114/stsi/research/e-VLBI/UT1/

Hayabusa Sessions http://www.nict.go.jp/w/w114/stsi/research/Navi/HAYABUSA/

The responsibilities for maintenance of these server machines were moved from the VLBI research group of NICT to the common division for the institutional network service of the laboratory

in 2001 to improve the network security of these systems.

168 IVS 2007 Annual Report
Kashima Space Research Center, NICT Data Center at NICT

2. Data Products

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 (once every two days) basis until May

1999. The duration of each session was about 23.5 hours. Within that period, daily observations

were performed from March 1 to April 1, 1999 to obtain continuous VLBI data series for various

investigations such as studies about the atmospheric delay models and for the improvements of

the data analysis technique. The high-speed ATM (Asynchronous Transfer Mode) network line

to the Miura station became unavailable in May 1999, and the real-time VLBI observations with

the Miura station became impossible. Thereafter, the real-time VLBI sessions were performed

with three stations only—Kashima, Koganei, and Tateyama. 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 three stations except for 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 Kashima, Miura, and Tateyama stations to Koganei station for tapebased correlation processing of the full 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 since July 22,

2000. The daily sessions were continued until November 11, 2000, and the site motion 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. 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. By investigating

the time series of the site positions, 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 addition to the KSP regular VLBI sessions, domestic and international geodetic VLBI

sessions were conducted by NICT in cooperation with Geographical Survey Institute (GSI) and

other organizations. These sessions are listed in Table 2. The observed data of these sessions were

correlated by using the K4 correlator and the K5 software correlator at NICT either at Koganei

or at Kashima.

In 2007, 35 geodetic VLBI sessions were performed in total. Ultra-rapid e-VLBI sessions were

performed based on the proposal submitted to and approved by the IVS Observing Program

Committee in May 2007. The purpose of these sessions is to demonstrate e-VLBI capabilities for

ultra-rapid data processing after intensive type short period (typically 1 hour) observing schedules.

Observed data at one site are transferred to the other site in real-time by using high speed research

IVS 2007 Annual Report 169
Data Center at NICT Kashima Space Research Center, NICT

Table 2. Geodetic VLBI sessions conducted by NICT (since 2005)

Year exp. names sessions

2005 Geodetic c0505 (CONT05, partial participation), GEX13

Hayabusa 14 sessions

2006 Geodetic GEX14, viepr2, CARAVAN (3 sessions)

Spacecraft Geotail: 1 session

Pulsar 1 session

2007 Ultra Rapid e-VLBI 15 times, 29 sessions

Time Comparison 4 sessions, 12 days in total

Cs-Gas-Cell 1 session

Spacecraft Hayabusa: 1 session

networks, and the format conversion and data correlation processing are done immediately after

the real-time file transfer. Thus, it is expected to provide the database with a minimum time

of latency after each session. Two stations in Japan, Tsukuba and Kashima, and two stations

in Europe, Onsala and Mets ̈ahovi, are the regularly participating stations, and Wettzell station

will participate when regular IVS intensive observation session (INT2) is used for the project.

Under the project, we are developing necessary software programs to realize real-time and near

real-time data processing and automated data analysis. Our goal is to release the database file

on the data center WWW server as soon as possible, as well as to release the analyzed results to

the wide community by using e-mail. For this purpose, 29 sessions were scheduled over 15 days.

The number of sessions performed on each day varies for different reasons. Sometimes, only one

session was scheduled and performed on one day, whereas 6 sessions were scheduled and performed

on November 26, 2007.

A series of time transfer sessions were also performed in 2007. The purpose of the sessions

is to evaluate the capability of geodetic VLBI experiments for precise and accurate time transfer

between Time and Frequency Laboratories located worldwide. At first, two one-day sessions were

performed on January 11th and 22nd, 2007. Then a 3-day session was performed from February

28th, and a one-week continuous session was performed from June 15th.

One geodetic VLBI session was performed on the baseline between Kashima 34-m station

and Koganei 11-m station to evaluate the performance of the Laser Diode pumped Cesium gas

cell type frequency standard system. This frequency standard has been developed by Anritsu

Corporation to provide better frequency stability at the short time scale less than one day compared

with the normal Cesium beam type frequency standard system. The system has a frequency

stability reaching 2 × 10−14 for a time interval of about 1000 seconds. Although the performance

of the frequency stability is not as good as hydrogen maser frequency standard systems, it was

demonstrated that the system can be used for geodetic VLBI observations.

In addition, one VLBI session was performed on March 7, 2007 to determine the precise orbit

of the Hayabusa spacecraft. It was planned to perform maneuver operation of the spacecraft to

return to the Earth, and the precise orbit information was necessary.

Figure 1 shows the number of geodetic VLBI sessions and number of valid observed delays used

in the data analysis for each year up to the year 2007.

170 IVS 2007 Annual Report
Kashima Space Research Center, NICT Data Center at NICT

Figure 1. Number of sessions (left) and observed delays (right) used in the data analysis.

3. Staff Members

The data center at NICT is operated and maintained by the Space-Time Standards Group at

Kashima Space Research Center, NICT. The staff members are listed in Table 3.

Table 3. Staff members of Space-Time Standards Group, KSRC, NICT

Name Main Responsibilities

KOYAMA Yasuhiro Administration of Servers, Generation and Archival of Databases

SEKIDO Mamoru Responsible for e-VLBI sessions

TSUTSUMI Masanori System Engineer

4. Future Plans

Although the regular VLBI sessions with the KSP VLBI network finished in 2001, the IVS

Data Center at NICT will continue its service and will archive and release the analysis results

accumulated by the Correlation Center and 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

[2] Koyama, Y., T. Kondo, M. Kimura, and H. Takeuchi, IVS NICT TDC News, No. 26, Sep. 2005, pp.

9-12

IVS 2007 Annual Report 171
Paris Observatory (OPAR) Data Center Observatoire de Paris, SYRTE/UMR 8630

Paris Observatory (OPAR) Data Center

Christophe Barache

Abstract

This report summarizes the OPAR Data Center activities in 2007. Included is information about

functions, architecture, status, future plans and staff members of OPAR Data Center.

1. OPAR Data Center Functions

The Paris Observatory (OPAR) has provided a Data Center for the International VLBI Service

for Geodesy and Astrometry (IVS) since 1999. The OPAR, along with 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 (auxilliary, database, products, documents),

• mirrors the other ones every three hours,

• gives free FTP access to the files.

BKG

(USA) (GERMANY)

CDDIS OPAR

(FRANCE)

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.

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 total number of OPAR Data Center

submission failures is rather small (around five this year); errors mostly consisted of file name

172 IVS 2007 Annual Report
Observatoire de Paris, SYRTE/UMR 8630 Paris Observatory (OPAR) Data Center

errors or files uploaded by mistake. The script undergoes permanent improvement and takes into

account the IVS components’ requests.

The structure of IVS Data Centers is:

ivscontrol/ : provides the control files needed by the data center

(session code, station code, solution code...)

ivscontrol_new/ : temporary test directory

ivscontrol_old/ : temporary test directory

ivsdocuments/ : provides documents and descriptions about IVS products

ivsdata/ : provides files related to the observations:

aux/ : auxilliary files (schedule, log...)

db/ : observation files in data-base CALC format

ngs/ : observation files in NGS format

sinex/ : observation files in SINEX format

ivsproducts/ : provides results from Analysis Center:

eopi/ : Earth Orientation Parameters, intensive sessions

eops/ : Earth Orientation Parameters, sessions of 24h

crf/ : Celestial Reference Frame

trf/ : Terrestrial Reference Frame

daily_sinex/ : Time series solutions in SINEX format of Earth

orientation and site positions

int_sinex/ : Daily Intensive solution in SINEX format, mainly

designed for combination

trop/ : Tropospheric time series (starting July 2003)

ivs-iers/ : provides products for IERS Annual Report

ivs-pilot2000/ : provides products of 2000 for special investigations

ivs-pilot2001/ : provides products of 2001 for special investigations

ivs-pilottro/ : provides tropospheric time series for Pilot Project

(until June 2003)

ivs-pilotbl/ : provides baseline files

ivs-special/ : specific studies

raw/ : original data (not writable actually at OPAR Data Center)

3. Current Status

The OPAR Data Center is operated actually on a PC Server (PowerEdge 2800—Xeron 3.0

GHz) located at 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 600 GB disk extensible up to 4.7 TB.

The OPAR server is accessible 24 hours per 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.

IVS 2007 Annual Report 173
Paris Observatory (OPAR) Data Center Observatoire de Paris, SYRTE/UMR 8630

FTP access:

ivsopar.obspm.fr

username : anonymous

password : your e-mail

cd vlbi (IVS directory)

4. Future Plans

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

ensure better access and also make raw data available in the OPAR Data Center, we have acquired

new disks to get 3 TB for data storage. Their installation is planned for the beginning of 2008,

together with the implementation of the dserver package.

5. Staff Members

Staff members who are contributing to the OPAR Data Center and the OPAR Analysis Center

for IVS are listed below :

• Christophe Barache, Data Center manager and Data Analysis.

• Anne-Marie Gontier, responsible for GLORIA Analysis Software.

• S ́ebastien Lambert, scientific developments.

• Daniel Gambis, interface with IERS activities.

To obtain information about the OPAR Data Center please contact: ivs.opa@obspm.fr

174 IVS 2007 Annual Report
Analysis Centers

Geoscience Australia Geoscience Australia Analysis Center

Geoscience Australia Analysis Center

Oleg Titov

Abstract

This report gives an overview about activity of the Geoscience Australia IVS Analysis Center during

the year 2007.

1. General Information

The Geoscience Australia (GA) IVS Analysis Center is located in Canberra. The Geodesy

group operates as a part of the Geospatial and Earth Monitoring Division (GEMD).

2. Component Description

Currently the GA IVS Analysis Center contributes nutation offsets, three EOPs and their rates

on a regular basis for IVS-R1 and IVS-R4 networks and their predeccesors (IRIS-A, NEOS-A).

The EOP time series from 1983 to 2007 are available. The CRF catalogues using a global set of

VLBI data since 1979 are regularly submitted. In addition the GA Analysis Center participates

in the statistical analysis of baseline length repeatabilities.

3. Staff

• Dr. Oleg Titov - project manager

4. Current Status and Activities

Several CRF solutions have been prepared using the OCCAM 6.2 software. VLBI data comprising 3555 daily sessions from 25-Nov-1979 to 26-Apr-2007 have been used to compute several

global solutions with different sets of reference radio sources. This includes 3,930,655 observational

delays from 2066 radio sources observed by 60 VLBI stations.

The last four solutions (aus000a,aus001a,aus002a,aus003a) were submitted within the scope

of the IERS/IVS Working Group on the Second Realization of the ICRF. The aus000a solution

strategy used all radio sources as global parameters. The aus001a solution strategy used radio

sources as close as possible to the ICRF [1]. Coordinates of 102 ‘other’ ICRF sources were treated

as local parameters and their positions were estimated for each VLBI session. The rest of the

sources were treated as global parameters. The aus002a solution treated as global parameters only

582 radio sources which satisfy two conditions: 1) z≥1 and 2) not ‘unstable’ in the classification

by Feissel-Vernier [2]. The aus003a solution treated as global parameters only 486 radio sources

which satisfy two conditions: 1) z≤1 and 2) not ‘unstable’. Statistics of these solutions are shown

in Table 1.

Station coordinates were also estimated using NNR and NNT constraints. Long-term time

series of the station coordinates have been established to estimate the corresponding velocities

for each station. Due to a limited amount of observations the velocities have been estimated

for 55 stations only. Velocities of five stations (DSS65A, MARCUS, METSAHOV, VLBA85 3,

IVS 2007 Annual Report 177
Geoscience Australia Analysis Center Geoscience Australia

Table 1. Statistics of CRF solutions

Solution Number of

global sources

Number of arc

sources

Weighted

rms (pks)

chi-squared

aus008a all 15.4 0.866

aus008b 212 defining 102 other 15.2 0.862

aus008c 582 z≥1 1495 15.1 0.860

aus008d 486 z≤1 1591 15.5 0.905

and ZELENCHK) were not estimated. Tectonic motion for Gilcreek VLBI site after the Denali

earthquake is modeled using an exponential function [4].

The adjustment has been done by least squares collocation method, [5] which considers the

clock offsets, wet troposphere delays and troposphere gradients as stochastic parameters with

apriori covariance functions. The gradient covariance functions were estimated from the GPS

hourly values [3].

5. Geodetic Activity of the Australian Radiotelescopes

During 2007 two Australian radiotelescopes (Hobart and Parkes) were involved in geodetic

VLBI observations. The GA geodesy group promoted the observations in different ways.

The Parkes 64-meter telescope participated in five geodetic VLBI sessions in 2007. Five sessions

are planned for 2008 year. This program is promoted in cooperation with the Australian Telescope

National Facility (ATNF). The last two sessions in November were recorded with Mark 5B recorder.

6. New Geodetic VLBI Network

In November, 2006 the geospatial bid within the National Collaborative Research Infrastructure

Strategy (NCRIS) capability “Structure and Evolution of the Australian Continent” has been

approved. The VLBI part of this bid includes three new modern VLBI sites to be built in different

parts of the Australian continent. The proposed design includes small size dish (12 m) with

high slewing rate (5 degrees/second) equipped with Mark 5B recorder. First telescope in Hobart is

expected to be installed in 2008, two other telescope (Yarragadee, Western Australia and Katherine,

Northern Territory) will be built in 2009. The radio astronomy group of UTAS takes responsibility

for this network deployment.

7. Baseline Length Repeatability Analysis

Traditionally the baseline length repeatability is used as a measure of the quality of geodetic

VLBI data. The repeatability R used to be fit by a linear model as a function of baseline length

L only as R = aL + b. However, it was shown that the simple linear regression does not fit long

baselines properly (e.g., [6], [7]).

It was shown [8] that the repeatability R can be fitted as a function of two parameters: baseline

length L and slewing rate of radio dish V . Then the following expression can be given for R:

178 IVS 2007 Annual Report
Geoscience Australia Geoscience Australia Analysis Center

R

2 =

AL2 + B

√

V (C − DL)

Here A,B,C,D are empirical parameters to be estimated by least squares. Fig 1 demonstrates

the empirical values of the repeatabilities versus baseline length (black dots) and their approximation by the proposed formula (circles).

Figure 1. Fitting of the empirical relationship ‘repeatability vs baseline length’ (top) and post-fit residuals

(bottom).

IVS 2007 Annual Report 179
Geoscience Australia Analysis Center Geoscience Australia

The horizontal and vertical uncertainties (σh and σv) can be also calculated using the same

empirical values plus the radius of the Earth Re as:

σh =

√

B

q

2

√

V (C − DL)

σv =

s

σ

2

h +

2AR2

√ e

V (C − DL)

More details are available in [8].

References

[1] Ma, C., E. Arias, T. Eubanks, A. Fey, A.-M. Gontier, C. Jacobs, O. Sovers, B. Archinal, P. Charlot,

The International Celestial Reference Frame as realized by Very Long Baseline Interferometry, In: AJ,

116, 516–546, 1998.

[2] Feissel-Vernier, M., Selecting stable extragalactic compact radio sources from the permanent astrogeodetic VLBI program, In: AJ, 403, 105–110, 2003.

[3] Haas, R., private communication.

[4] Titov, O., P. Tregoning, Post-seismic motion of the Gilcreek geodetic sites following the November,

2002 Denali Earthquake, In: International VLBI Service for Geodesy and Astrometry 2004 General

Meeting Proceedings, NASA/CP–2004-212255, N. R. Vandenberg and K. D. Baver (eds.), 496–500,

2004.

[5] Titov, O., Estimation of subdiurnal tidal terms in UT1-UTC from VLBI data analysis In: IERS

Technical Notes 28, B. Kolaczek, H. Schuh and D. Gambis (eds.), 11–14, 2000.

[6] MacMillan, D. D., D. Behrend, D. Gordon, C. Ma, First Results from CONT05 In: International

VLBI Service for Geodesy and Astrometry 2006 General Meeting Proceedings, NASA/CP–2006-214140,

D. Behrend and K. D. Baver (eds.), 269–273, 2006.

[7] Lambert, S., Baseline and Site Repeatability in the IVS rapid Network, In: International VLBI Service

for Geodesy and Astrometry 2006 General Meeting Proceedings, NASA/CP–2006-214140, D. Behrend

and K. D. Baver (eds.), 296–299, 2006.

[8] Titov, O., Baseline length repeatability In: Proc of 18 European VLBI on Geodesy and Astrometry

Working Meeting, J. Boehm, A. Pany and H. Schuh (eds.), 64–68, 2007.

180 IVS 2007 Annual Report
Observatoire de Bordeaux Bordeaux Observatory Analysis Center

Bordeaux Observatory Analysis Center Report

Patrick Charlot, Antoine Bellanger, G ́eraldine Bourda, Arnaud Collioud, Alain Baudry

Abstract

This report summarizes the activities of the Bordeaux Observatory Analysis Center in 2007. During

this period, we have continued the VLBI imaging activity initiated previously. A total of 574 VLBI

maps have been produced by full imaging of three RDV sessions. Other activities focus on regular

processing of the IVS-R1 and IVS-R4 sessions and calculation of additional structure indices to refine

our source categorization based on this criterion. Newly developed activities include simulations to

study the imaging capabilities of the next generation VLBI system and, on the observational side,

the initiation of a VLBI survey of weak sources that are potential candidates to link the ICRF and

the future GAIA frame. Plans for 2008 follow the same analysis and research lines, with also specific

contributions in the framework of the Working Group on the Second Realization of the International

Celestial Reference Frame.

1. General Information

The Bordeaux Observatory is located in Floirac, near the city of Bordeaux, in the southwest of

France. It is funded by the University of Bordeaux and the CNRS (National Center for Scientific

Research). VLBI analysis and research activities are primarily developed within the M2A group

(“M ́etrologie de l’espace, Astrodynamique, Astrophysique”) led by P. Charlot.

The contribution of Bordeaux Observatory to IVS has been mostly concerned with the maintenance, extension, and improvement of the International Celestial Reference Frame (ICRF). This

includes regular VLBI imaging of the ICRF sources and evaluation of their astrometric suitability,

as well as developing specific VLBI observing programs aimed at extending the frame.

In addition, the Bordeaux group is in charge of the VLBI component in the multi-technique

GINS software [1] as part of a collaborative effort within the French “Groupe de Recherches de

G ́eod ́esie Spatiale” (GRGS) to combine VLBI and space geodetic data (SLR, GPS, DORIS) at the

observation level. This effort also involves space geodesy groups in Toulouse, Grasse, and Paris.

2. Description of Analysis Center

The Bordeaux Observatory Analysis Center routinely analyzes the weekly IVS-R1 and IVS-R4

sessions. This analysis is now based on the GINS software, whereas it was carried out with the

JPL VLBI estimation software MODEST [2] in previous years. Results derived with GINS have

been checked against IVS solutions [3]. In the fall of 2007, we installed the Linux version of GINS

(GINS-PC) in Bordeaux, which should facilitate the production of future operational solutions.

Another activity is focused on producing VLBI maps of the ICRF sources by analysis of data

from the RDV sessions. This analysis is conducted with the AIPS and DIFMAP calibration and

imaging software. The aim of such regular imaging is to compare source structural evolution and

positional instabilities. The maps are also used to derive “structure indices” in order to characterize

the astrometric suitability of the sources. Such studies will be important in the framework of the

realization of the next ICRF by a joint IAU/IVS/IERS working group within the coming year.

In addition, the Bordeaux group has been involved in the VLBI2010 activities. This includes

studies of source structure effects from wide band delay measurements and simulations of VLBI

maps for the evaluation of the imaging capabilities of VLBI2010 test networks.

IVS 2007 Annual Report 181
Bordeaux Observatory Analysis Center Observatoire de Bordeaux

3. Scientific Staff

The IVS group in Bordeaux comprises the following five individuals who are involved either

part time or full time in VLBI analysis and research activities, as described below:

• Patrick Charlot (50%): overall responsibility for Analysis Center work and data processing.

His major research interests include the densification and extension of the ICRF and studies

of source structure effects in astrometric VLBI data.

• Antoine Bellanger (100%): engineer with background in statistics and computer science. His

main role is to conduct initial VLBI data processing and develop analysis tools as needed.

He is also the Web master for the M2A group.

• G ́eraldine Bourda (50%): postdoc fellow funded by the French space agency (CNES). She is in

charge of the VLBI analysis with GINS for combining space geodesy data at the observation

level. She is also leading an observing program for linking the ICRF and the GAIA frame.

• Arnaud Collioud (100%): engineer with background in astronomy and interferometry. His

task is to process the RDV sessions with AIPS and DIFMAP for imaging the sources. In

addition, he develops simulations to study the imaging capabilities of VLBI2010 networks.

• Alain Baudry (10%): radioastronomy expert with specific interest in radio source imaging

and astrometric VLBI.

4. Analysis and Research Activities during 2007

As noted above, a significant part of our activity consists of systematic imaging of all extragalactic sources observed during the RDV sessions. During the past year, three such sessions have

been processed (RDV26, RDV62, and RDV64), resulting in 574 VLBI images at either X or S band

for 200 different sources. See Fig. 1 for a sample of the images derived from the RDV64 session,

observed on 2007 July 10. Overall, we have now produced a total of 1122 images for 264 different

sources. The imaging work load has been shared between USNO and Bordeaux Observatory since

2007: the USNO group processes the odd-numbered RDV sessions while the Bordeaux group processes the even-numbered ones. In addition, we collaborate with Whittier College (USA) and the

Max Planck Institute for Radioastronomy in Bonn for analysis of the earlier RDV sessions.

In order to make these images available, we have developed a prototype database which also

includes the structure correction maps and structure indices derived from the VLBI images. Calculation of structure indices is useful to categorize the sources and to identify those that remain

astrometrically suitable over time. Based on our VLBI images and those from the Radio Reference

Frame Image Database (RRFID), we have obtained 2697 structure indices at X band (from 577 different ICRF sources) and 2388 structure indices at S band (from 492 different ICRF sources), with

up to 28 VLBI epochs available for the most intensively observed sources [4]. Among these, there

are about 200 sources that are found to be astrometrically suitable at any epoch. Such sources are

potential candidates to serve as defining sources in the next realization of the ICRF.

During the past year, we also initiated a new VLBI observational program dedicated to observing 450 weak sources that are potential candidates to link the ICRF and the future GAIA frame.

These candidates were selected on the basis of their optical counterpart (V ≤ 18), their total flux

density (S ≥ 20 mJy) and their declination (δ ≥ −10◦) so that they can be observed with northern

182 IVS 2007 Annual Report
Observatoire de Bordeaux Bordeaux Observatory Analysis Center

Figure 1. VLBI images at X band (upper panel) and S band (lower panel) for three ICRF sources (0458−020,

1519−273, and 1606+106) as derived from the data of the RDV64 session conducted on 2007 July 10.

VLBI arrays. Pilot observations were carried out with the European VLBI Network (EVN) in

June and October 2007 in order to identify which sources are detectable with VLBI. Interestingly,

about 90% of the targets turned out to be detected, with typical VLBI flux densities of 25 mJy at

X band and 45 mJy at S band [5]. This very high detection rate sets excellent prospects for follow

up imaging and precise astrometry on these targets and, in the longer term, for the ICRF–GAIA

link.

Another activity that was initiated during the past year is the study of the imaging capabilities

of the next generation VLBI system as a contribution to the work of the VLBI2010 Committee.

To this end, a pipeline that simulates VLBI images from VLBI2010 schedules has been developed. Based on this pipeline, simulated VLBI images have been successfully produced for various

schedules depending on the network configuration, the number of observations per day, and the

observing strategy. A major conclusion of this study is that a 16-station network fails to properly

reconstruct extended structures for sources at low declination, whereas a 32-station network reconstructs such structures in a reliable way for sources at any declination. Details of the pipeline

and results of the simulations will be reported at the forthcoming IVS General Meeting [6].

IVS 2007 Annual Report 183
Bordeaux Observatory Analysis Center Observatoire de Bordeaux

5. Outlook

For the year 2008, our plans include the following:

• Keep on analyzing the new IVS-R1 and IVS-R4 sessions as they become available and develop

appropriate procedures for future operational analysis with GINS.

• Continue the processing of the RDV sessions to monitor the X and S band structural variability of the ICRF sources in cooperation with USNO and other groups that contribute to

the imaging of these sessions.

• Continue to evaluate the astrometric suitability of the ICRF sources as new maps become

available and categorize the sources according to our structure index criterion.

• Contribute to the work of the IAU/IVS/IERS Working Group on the Second Realization of

the ICRF with emphasis on the selection of defining sources and identification of unstable

sources.

• Finalize the prototype database that holds our source maps, structure correction maps, and

structure indices so that these can be made publicly available through the Web.

• Pursue further our studies of the imaging capabilities of the next generation VLBI system

by carrying out additional simulations within the framework of the VLBI2010 Committee.

References

[1] Meyer, U., Charlot, P., Biancale, R.: 2000, GINS: A New Multi-technique Software for VLBI Analysis,

IVS 2000 General Meeting Proceedings, Eds. N. R. Vandenberg and K. D. Baver, NASA/CP-2000-

209893, p. 324–328.

[2] Sovers, O. J., Jacobs, C. S.: 1996, Observation Model and Parameter Partials for the JPL VLBI

Parameter Estimation Software “MODEST”–1996, JPL Publication 83-39, Rev. 6, August 1996.

[3] Bourda, G., Charlot, P., Biancale, R.: 2007, GINS: A New Tool for VLBI Geodesy and Astrometry,

Proceedings of the 18th European VLBI for Geodesy and Astrometry Working Meeting, Eds. J. B ̈ohm,

A. Pany, and H. Schuh, IGG Vienna, p. 59–63.

[4] Charlot, P., Fey, A., Collioud, A., Ojha, R., Boboltz, D., Camargo, J. I. B.: 2008, Source structure: an

essential piece of information for generating the next ICRF, Proceedings of the IAU Symposium 248,

A Giant Step: from Milli- to Micro-arcseond astrometry, Shanghai, 15–19 October 2007 (in press).

[5] Bourda, G., Charlot, P., Porcas, R., Garrington, S.: 2008, Multi-step VLBI observations of weak

extragalactic radio sources to align the ICRF and the future GAIA frame, to be presented at the 5th

IVS General Meeting, March 3–6, 2008, Saint Petersburg (Russia).

[6] Collioud, A., Charlot, P.: 2008, Imaging capabilities of the next generation VLBI system, to be presented at the 5th IVS General Meeting, March 3–6, 2008, Saint Petersburg (Russia).

184 IVS 2007 Annual Report
Centro di Geodesia Spaziale (CGS) - Telespazio Matera CGS VLBI Analysis Center

Matera CGS VLBI Analysis Center

Roberto Lanotte, Giuseppe Bianco, Cinzia Luceri

Abstract

This paper reports the VLBI data analysis activities at the Space Geodesy Center (CGS) at Matera

from January 2007 through December 2007 and the contributions that the CGS intends to provide for

the future as an IVS Data 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. VLBI data analysis activities are performed at CGS for

a better understanding of the tectonic motions with specific regards to the European area. The

CGS, operated by Telespazio on behalf of ASI, provides full scientific and operational support

using the main space geodetic techniques: VLBI, SLR, and GPS.

2. Staff at CGS Contributing to the IVS Analysis Center

- Dr. Giuseppe Bianco, Responsible for CGS/ASI (primary scientific/technical contact).

- Dr. Cinzia Luceri, Responsible for scientific activities, e-GEOS.

- Dr. Roberto Lanotte, Geodynamics data analyst, Telespazio.

3. Current Status and Activities

3.1. Global VLBI Solution asi2007a

The main VLBI data analysis activities at the CGS in the year 2007 were directed towards

the realization of a global VLBI analysis, named asi2007a, using the CALC/SOLVE software

(developed at GSFC). The main characteristics of this solution are:

• Data span:

1979.08.03 - 2007.12.27 (3463 sessions)

• Estimated Parameters:

– Celestial Frame:

right ascension and declination as global parameters for 637 sources

– Terrestrial Frame:

Coordinates and velocities for 92 stations as global parameters

– Earth Orientation:

Unconstrained X pole, Y pole, UT1, Xp rate, Yp rate, UT1 rate, dpsi, and deps.

IVS 2007 Annual Report 185
Matera CGS VLBI Analysis Center Centro di Geodesia Spaziale (CGS) - Telespazio

3.2. IVS Tropospheric Products

Regular submission of tropospheric parameters (wet and total zenith path delays, east and

north horizontal gradients) for all VLBI stations observing in the IVS R1 and R4 sessions was

continued during 2007. At present 493 sessions have been analyzed and submitted covering the

period from 2002 to 2007. The results are available on the IVS products ftp sites.

3.3. IVS Pilot Project “Time Series of Baseline Lengths”

Regular submission of station coordinate estimates, in SINEX files, was continued during 2007

for the IVS pilot project “Time Series of Baseline Lengths”. The series is composed of 3167

sessions, from 1979 to 2007. At the present, an analysis of the differences between the CGS series

and those provided by the analysis centers participating in this project is under investigation.

4. Future Plans

• Continue to improve the realization of global VLBI analysis.

• Continue to participate in IVS analysis projects.

186 IVS 2007 Annual Report
DGFI, Deutsches Geod ̈atisches Forschungsinstitut DGFI Analysis Center

DGFI Analysis Center Annual Report 2007

Volker Tesmer, Hermann Drewes, Manuela Kr ̈ugel

Abstract

This report summarizes the activities of the DGFI Analysis Center in 2007 and outlines the planned

activities for the year 2008.

1. General Information

The German Geodetic Research Institute (Deutsches Geod ̈atisches Forschungsinstitut, DGFI)

is an autonomous and independent research institution located in Munich. It is run by the German

Geodetic Commission (Deutsche Geod ̈atische Kommission, DGK) at the Bavarian Academy of Sciences. The research covers all fields of geodesy and includes the participation in national and international projects as well as functions in international bodies (see also http://www.dgfi.badw.de).

2. Activities in 2007

1. Common signals in homogeneously reprocessed long-term GPS and VLBI height time series

The intention was to understand how station position time series improve, if latest high-end

models are used in geodetic data analysis. One criteria that can be applied is the similarity

of annual harmonic signals estimated from GPS and VLBI height series. We used GPS and

VLBI height time series with daily resolution (data from 94-07), computing 2 solution runs:

• Iteration 1: Both series are fully reprocessed and the a priori models were homogenized

in both softwares (GPS: Bernese 5.1 @ GFZ, VLBI: OCCAM 6.1 @ DGFI); Nevertheless,

not all models were state-of-the-art (e.g., NMF, constant a priori ZD).

• Iteration 2: Besides the efforts in iteration 1, all models were updated according to the

latest state of knowledge (e.g., VMF1, a priori ZD from ECMWF, thermal deformation

for VLBI, the VLBI ZD was estimated in full UTC hours as for GPS).

Figure 1. Annual harmonic signals estimated from GPS and VLBI height time

series. The arrows illustrate the estimated amplitudes and phases of 17 stations with enough data (dark is VLBI,

light grey is GPS). The figure shows the

results of iteration 2, which is related to

state-of-the-art models.

Figure 1 illustrates the GPS and VLBI annual signals estimated from the iteration 2 data.

Considering the WRMS of the VLBI vs GPS differences in phase and amplitude for all

stations (iteration 1 / 2: WRMS amplitude 2.2 / 1.7 mm, WRMS phase 44 / 38 deg), one

can assume that the iteration 2 modeling is clearly better.

IVS 2007 Annual Report 187
DGFI Analysis Center DGFI, Deutsches Geod ̈atisches Forschungsinstitut

2. Alternative models to estimate nutation and polar motion rates

In VLBI data analysis, it is common practice to determine the full set of EOP (dUT1 and

LOD, polar motion and their rates as well as nutation offsets) for each 24-h VLBI session.

For that, we have a mathematical correlation of the nutation offsets and the terrestrial pole

rates, as illustrated in Figure 2 (because nutation offsets are equivalent to a retrograde daily

oscillation in the terrestrial frame).

Figure 2. Correlation coefficients between nutation offsets and terrestrial

pole rates, estimated from the 2004-

2006 session SINEX files, submitted to

the IVS by DGFI. The annual variation of the correlation reflects the annual change in phase of the retrograde

daily oscillation due to a superposition

of the sidereal and the solar day.

Therefore, efforts were made to estimate nutation parameters not for each session, but for

several sessions or even weeks, which would lead to a considerable improvement if the deficiencies of the a priori nutation model are only the free core nutation (FCN, with a period

of about 432 days). Like this, we could stabilize the nutation estimates, which thus would

help to improve the polar motion rate estimates for each session.

Preliminary results indicate that the WRMS of the differences between the dX pole rates and

the IGS values is getting smaller, the WRMS of the differences of the dY pole rates does not

change significantly. An analysis of the daily nutation estimates reveals the reason for the

only moderate improvement: the IAU2000A nutation model has small insufficiencies in the

shorter periods, like the fortnightly lunar (Mf) 13.661 days period, with residual amplitude

of about 0.06 mas. Thus, before repeating these tests, the nutation model has to be improved

in the higher frequencies.

3. Effect of analyis options in results from the IVS standard SINEX normal equations

In close cooperation with the VLBI group of the University of Bonn, the results from two

VLBI analysis software packages, OCCAM and Calc/Solve, were compared to detect systematic differences, caused by model differences. The comparisons were carried out with EOP

and station position time series calculated from standard normal equations (SINEX files), as

used for the official IVS combination (contributions are from DGFI and the NASA Goddard

Space Flight Center). In addition, the same comparisons were done with consistent time series generated with all relevant corrections adapted in both software packages (contributions

from DGFI and the VLBI group of the University of Bonn, IGGB).

Comparing the GSFC(IVS)–DGFI(IVS) differences to the IGGB–DGFI differences, systematics became obvious. Many stations had systematic height offsets of about 1 cm in the

GSFC(IVS)–DGFI(IVS) case, but not for IGGB–DGFI (horizontal differences were smaller

by a factor of 3). These systematic differences turned out to be mainly due to differences in

the pole tide model.

188 IVS 2007 Annual Report
DGFI, Deutsches Geod ̈atisches Forschungsinstitut DGFI Analysis Center

4. DGFI contribution to the second realization of the ICRF (ICRF2)

DGFI takes part in the IVS Working Group for the second realization of the ICRF (ICRF2)

by submitting all types of results necessary in this context. The first goal is to identify sources

which cannot be assumed to have positions constant in time, by computing and analyzing

time series of estimated source positions. DGFI computes such time series using a NNR

datum over all sources per session with respect to a homogeneous CRF solution.

Figure 3 (upper panel) shows the time series of declination components of the source 1741-

038, with only NNR conditions applied for each single session. An annual signal can clearly

be seen, which is possibly caused by atmospheric mismodeling in data analysis, although the

respective source code in OCCAM is fully up-to-date with the latest models in this area of

research. If some deformation parameters (see legend of Figure 3) are also estimated (panel

in the middle: IERS approach, lower panel: DGFI approach), this signal is absorbed.

Figure 3. Time series of declination components for the source 1741-038. Upper

panel: positions are estimated for each

session, with only NNR datum applied.

Panel in the middle: with a deformation model also estimated, which is often used in the IERS and the astrometric community (for declination δ: Dδ(δδ0) + dz , for right ascension α:Dα(δ-δ0)).

Lower panel: estimated with NNR datum

and a simpler but very effective deformation model, developed at DGFI (for declination δ: dz cosδ). Although still under

investigation, the DGFI model fits the data

well.

5. IVS Operational Analysis Center at DGFI

The IVS updated its approach to determine the operational IVS Earth Orientation Parameters (EOP) series from averaging solutions submitted by the different Analysis Centers (which

all used inhomogeneous solution setups, different reference frames etc), to computing them

from normal equations, which were derived by adding the SINEX files submitted to the IVS

by the different Analysis Centers (ACs). These files contain the EOP and station positions

for each 24-hour session as SINEX normal equations, which provides a direct relation of the

EOP to one definite TRF throughout the whole series (e.g., the ITRF2005). This approach

also allows to analyze the input data in a much better way than before and is especially suitable to rigorously reprocess the combination, if necessary. The DGFI IVS AC contributed to

this new operational series from its beginning in December 2006 with a recomputed series of

datum-free normal equations in SINEX format for VLBI sessions back to 1984 (3050 sessions

at the end of 2007).

IVS 2007 Annual Report 189
DGFI Analysis Center DGFI, Deutsches Geod ̈atisches Forschungsinstitut

6. IVS OCCAM Working Group

Most important for DGFI as IVS AC is to maintain and refine the VLBI software OCCAM to

current requirements in close collaboration within the IVS OCCAM Working Group, chaired

by Oleg Titov, Geoscience Australia (Canberra, Australia). Other leading members are

scientists from the Vienna University of Technology, Austria, the St. Petersburg University,

the Institute of Applied Astronomy, both Russia, and DGFI. The latest updates of the

software package are related to an optional homogenization effort with the Bernese GPS

Software and post-fit analysis tools to analyze station and radio source position time series.

3. Staff

Members of the DGFI IVS AC are Volker Tesmer, Manuela Kr ̈ugel, and Hermann Drewes.

4. Plans for 2008

In 2008, it is planned to further improve the VLBI software OCCAM, support IVS TRF and

CRF preparation activities (submit solutions computed at DGFI and analyze different contributions), and to submit SINEX files for all 24-h sessions to the IVS on an operational basis.

5. Selected Publications

Artz, T., S. B ̈ockmann, A. Nothnagel, V. Tesmer: ERP time series with daily and sub-daily

resolution determined from CONT05. J. Boehm, A. Pany, H. Schuh (Eds.): Proc. of the 18th

EVGA Working Meeting, 12-13 April 2007, Geowiss. Mitteilungen, Heft Nr. 79, TU Wien, ISSN

1811-8330, 69-74, 2007

B ̈ockmann, S., T. Artz, A. Nothnagel, V. Tesmer: Comparison and combination of consistent

VLBI solutions. J. Boehm, A. Pany, H. Schuh (Eds.): Proc. of the 18th EVGA Working Meeting,

12-13 April 2007, Geowiss. Mitteilungen, Heft Nr. 79, TU Wien, ISSN 1811-8330, 82-87, 2007

Heinkelmann, R., J. Boehm, S. Bolotin, G. Engelhardt, D. MacMillan, H. Schuh, E. Skurikhina,

V. Tesmer, O. Titov, P. Tomasi: Combination of long time series of troposphere zenith delays observed by VLBI. In: Schuh, H., A. Nothnagel, C. Ma (Eds.): VLBI special issue. Journal of

Geodesy, DOI 10.1007/s00190-007-0147-z, 2007

Schuh, H., R. Heinkelmann, J. Sokolova, V. Tesmer: Sub-Commission 1.4 Interaction of Celestial and Terrestrial Reference Frames. IAG Commission 1 Reference Frames, Report 2003-2007,

Bulletin No. 20, ed. By H. Drewes and H. Hornik, DGFI, Munich, pp. 46-51, 2007

Tesmer, V.: Celestial Reference Frames and Interaction with Terrestrial Reference Frames. In:

M ̈uller, J., H. Hornik (Eds.): National Report of the Federal Republic of Germany on the Geodetic

Activities in the years 2003-2007. Deutsche Geod ̈atische Kommission, Reihe B, Nr. 315, M ̈unchen,

11-13, 2007

Tesmer, V.: Effect of various analysis options on VLBI-determined CRF. J. Boehm, A. Pany,

H. Schuh (Eds.): Proc. of the 18th EVGA Working Meeting, 12-13 April 2007, Geowiss. Mitteilungen, Heft Nr. 79, TU Wien, ISSN 1811-8330, 103-110, 2007

190 IVS 2007 Annual Report
Forsvarets forskningsinstitutt (FFI) (Norwegian Defence Research Establishment) FFI Analysis Center

FFI Analysis Center

Per Helge Andersen

Abstract

FFI’s contribution to the IVS as an analysis center focuses primarily on a combined analysis at the

observation level of data from VLBI, GPS, and SLR using the GEOSAT software. This report shortly

summarizes the current status of analyses performed with the GEOSAT software. FFI is currently

Analysis Center for IVS and ILRS, Technology Development Center for IVS, and Combination Research

Center for IERS.

1. Introduction

A number of co-located stations with more than one observation technique have been 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 co-located antennas is estimated using constraints in

accordance with a priori information given by the ground surveys. One set of Earth orientation

parameters (EOP) and geocenter coordinates can be estimated from all involved data types. 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 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

accounted for with the GEOSAT software developed by FFI.

After five years of development and extensive validation we are proud to announce that a

major revision and extension of the GEOSAT software has been completed. The most important

changes implemented have been described in recent IVS Annual Reports. Much more flexibility

and automation have been added. Furthermore, the latest and “best” models (mostly following the

IERS Standard) and “calibration tables” and “instrumental/geophysical events tables” have been

included. Analysis of tracking data to S/C’s in deep space has been added. For any technique,

the delay due to the troposphere is determined with 3D raytracing using the European Center for

Medium-range Weather Forcast Numerical Weather Model. No mapping functions are used and

the corrections are determined directly from interpolation in the raytracing files.

2. Staff

Dr. Per Helge Andersen - Research Professor of Forsvarets forskningsinstitutt (FFI) and Institute of Theoretical Astrophysics, University of Oslo.

IVS 2007 Annual Report 191
FFI Analysis Center Forsvarets forskningsinstitutt (FFI) (Norwegian Defence Research Establishment)

3. Combination of VLBI, GPS, and SLR Observations at the Observation Level

The processing of observations in GEOSAT is performed in three steps: 1) Omc step: for each

individual technique generate files of residuals (observed minus calculated, omc) and partials for

a period of “one arc” (usually 24 hours). Selected parameters are estimated to generate “small”

residuals so that iterating in the filter is not necessary. 2) Comb step: combine omc files for all

techniques at the epoch-by-epoch level using a UD (Upper-Diagonal factorized) sequential filter.

The result is a SRIF (Square-Root-Information-Filter) array for that specific arc. 3) Global step:

combine all arc SRIF arrays to generate a multi-year solution. The estimation is performed with

a CSRIFS (Combined Square-Root-Information-Filter-and-Smoother factorized) sequential filter.

To perform the analyses we have a dedicated array of 10 state-of-the-art LINUX work stations,

each with 4 cpu’s, 6 GB RAM, and 1 TB disk space. The status of the analysis by Jan 2008 is as

follows: The omc step is completed for the period 1 Jan 2000 to 31 Dec 2006 with approximately

175 GPS stations, 10-30 SLR stations, and 0-20 VLBI stations daily. This is a tremendeous

computation task which took approximately 1 month of computation time. When new and better

models become available the computation can automatically be repeated within half the time

since the raytracing files can be re-used. The first tests at the Comb step level is presently

being performed trying to determine an “optimal” mix of solve-for parameters, constraints, and

weighting.

Our plan is to take the seven years of data through all three steps within 1-2 year. The outcome

will be new realizations of TRF, CRF, and EOP relying on consistent models and estimation

strategies. As a by-product a file of estimated eccentricity vectors will be produced. After that

we plan to add 2007 and newer data and also data before 2000. We also plan to estimate GM

and some low-order gravity coefficients simultaneously with all the other parameters. This type

of analysis is along the lines of the ideas behind the GGOS project where geometry, gravity, and

Earth orientation are to be simultaneously and consistently determined.

192 IVS 2007 Annual Report
Bundesamt f ̈ur Kartographie und Geod ̈asie BKG/IGGB Analysis Center

The BKG/IGGB VLBI Analysis Center

Volkmar Thorandt, Axel Nothnagel, Gerald Engelhardt, Dieter Ullrich, Thomas Artz,

Sarah B ̈ockmann, Markus Vennebusch

Abstract

In 2007 the activities of the BKG/IGGB (former GIUB, only renamed) VLBI Analysis Center, as

in previous years, consisted of routine computations of Earth orientation parameter (EOP) time series

and 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. Routine computations of the

UT1—UTC Intensive observations include all sessions of the Kokee—Wettzell and Tsukuba—Wettzell

baselines and the networks Kokee—Svetloe—Wettzell and Ny- ̊Alesund—Tsukuba—Wettzell. At the

same time, new models have been implemented in the data analysis software and first contributions to

the Working Group on ICRF2 were finished at BKG. At IGGB the emphasis was placed on individual

research topics.

1. General Information

The BKG/IGGB VLBI Analysis Center has been established jointly by the Federal Agency for

Cartography and Geodesy (BKG), Leipzig, and the Institute of Geodesy and Geoinformation of the

University of Bonn (IGGB), formerly Geodetic Institute of the University of Bonn (GIUB). Both

institutions maintain their own analysis groups in Leipzig and Bonn but cooperate intensively in the

field of geodetic VLBI. The responsibilities include data analysis for generating IVS products as well

as special investigations with the goal of increasing accuracy and reliability. BKG is responsible for

the computation of time series of EOP and tropospheric parameters, the generation of SINEX files

for 24-hour VLBI sessions and for 1-hour Intensive sessions as well as for quarterly updated global

solutions for TRF and CRF realizations. Besides data analysis, the BKG group is also responsible

for the scheduling of the Tsukuba—Wettzell INT2 UT1—UTC observing sessions. IGGB continues

to host the office of the IVS Analysis Coordinator and carries out special investigations in the

technique of geodetic and astrometric VLBI. Details of the research topics of BKG and IGGB are

listed in Section 3.

2. Data Analysis

At BKG the Mark 5 VLBI data analysis software system Calc/Solve, release of October 10,

2007 [1], has been used for VLBI data processing. It is running under Fortran 90 on a machine

with an operating system GNU/Linux 2.6.5-7.97-smp. It includes the new Calc 10 implementation

for complying with the IAU 2000 Resolutions and the IERS Conventions 2003. The Calc/Solve

software was modified for using the Vienna Mapping Function (VMF1). Applying VMF1 in data

analysis requires a daily update of the VMF1 data from the server of the Technical University

of Vienna [2]. In addition, an independent technological software environment for the Calc/Solve

software is available. The latter is used for linking up the Data Center management with the

pre- and post-interactive part of the EOP series production and to monitor all Analysis and Data

Center activities (Data Center topics are described in the BKG Data Center report in this issue).

IVS 2007 Annual Report 193
BKG/IGGB Analysis Center Bundesamt f ̈ur Kartographie und Geod ̈asie

• Processing of correlator output

The BKG group continued the generation of calibrated databases for the sessions correlated

at the MPIfR/BKG Mark 5 Astro/Geo Correlator at Bonn (e.g. EURO, OHIG, T2) and

submitted them to the IVS Data Centers.

• Scheduling

BKG continued scheduling the INT2 Intensive sessions which are observed on the baseline

TSUKUBA-WETTZELL. Altogether 100 schedule files were created in 2007.

• IVS EOP time series

The new EOP time series bkg00010 differs from the previous one by several points. The data

analysis was made with the new mapping function VMF1 for modeling the tropospheric

delay correction. Mean pole offsets for pole tide were used to be in agreement with the IERS

Conventions 2003 recommended values. The modeling for 3 stations was refined by nonlinear site position variations estimation (GILCREEK, HRAS, PIETOWN). Furthermore

the new official list of the VLBI antenna axis offsets, status May 17, 2007 [3] and the a priori

VTRF2005 [4] were used in data processing.

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 has been computed and

the EOP time series bkg00010 was extracted. Altogether 3533 sessions were processed. The

main parameter types in this solution are globally estimated station coordinates and velocities

together with radio source positions. Minimal constraints for the datum definition were

applied to achieve no-net-rotation and no-net-translation for 26 selected station positions and

velocities with respect to VTRF2005 and no-net-rotation for 212 defining sources with respect

to ICRF-Ext.1 [5]. The station coordinates of the stations BADARY (Russia), CTVASTJ

(Canada), DSS65A (Spain), METSAHOV (Finland), ZELENCHK (Russia) were estimated

as local parameters in each session.

VMF1 was used in the new UT1 time series bkgint07 too. In addition to the observations

of both baselines KOKEE-WETTZELL and TSUKUBA-WETTZELL, also the networks

KOKEE-SVETLOE-WETTZELL and NYALESUND-TSUKUBA-WETTZELL, each with

a duration of about 1 to 1.5 hours, were processed regularly. Series bkgint07 was generated

with fixed TRF (VTRF2005) and fixed CRF derived from the global BKG solution for EOP

determination. The estimated parameter types were only UT1, station clock, and zenith

troposphere. A total of 2372 UT1 Intensive sessions were analyzed for the period between

1999.01.01 and 2008.01.07.

• Quarterly updated solutions for submission to IVS

Also in 2007 quarterly updated solutions were computed for the IVS products TRF and CRF.

There are no differences in the solution strategy compared to the continuously computed EOP

time series bkg00010. 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, 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, horizontal gradients) for all VLBI sessions

194 IVS 2007 Annual Report
Bundesamt f ̈ur Kartographie und Geod ̈asie BKG/IGGB Analysis Center

since 1984. The tropospheric parameters are directly extracted and transformed into SINEX

for tropospheric estimates from the results of the standard global solution for the EOP time

series bkg00010.

• Daily SINEX files

The VLBI group of BKG also continued the regular submissions of daily SINEX files for

all available 24 hours sessions as base solutions for the IVS time series of baseline lengths

and for combination techniques. In addition to the global solutions independent session

solutions were computed for the parameter types station coordinates, EOP, and nutation

parameters. The a priori datum for TRF is defined by the VTRF2005 and the fixed CRF

derived from the global complete BKG solution for EOP determination is used for the a

priori CRF information.

• SINEX files for Intensive sessions

Due to special requirements from IVS, SINEX files for Intensive sessions were created. The

parameter types are station coordinates, pole coordinates and their rates, and UT1 with

rate. But only the normal equations stored in the SINEX files are important for further

combination with other space geodetic techniques.

3. Research Topics

• ICRF2

The VLBI group at BKG is part of the IVS Working Group for the Second Realization of the

ICRF. An important step is the computation of time series for all radio sources. On the basis

of former investigations [6] a new set of time series for all radio sources was computed with

nearly no change in datum definition. It is planned to investigate the long-term stability of

radio sources based on the time series of radio source positions.

• Subdaily EOP

The estimation of subdaily ERP from continuous VLBI campaigns show significant degradations at the session boundaries due to the breaks in observing time caused by the change-over

time at the stations from one session to the next of approximately 30 minutes. As a consequence, high-frequency EOP time series with a resolution of less than two hours are disrupted

showing severe jumps in the time series unless strong constraints are applied. In order to

cope with this problem, a modified solution procedure for continuous VLBI campaigns was

implemented. Here, two consecutive sessions are linked through a stacking of the respective elements of the normal equation matrix so that observations before and after the break

contribute to the EOP parameters near the break.

Furthermore, investigations of the impact of different analysis options on the target parameters have been continued. As one result, corrections to the recent precession-nutation model

IAU2000a with values reported in the IERS C04 series have improved the results in terms

of WRMS w.r.t. GPS solutions since the effect on the retrograde term with a period of one

day is significantly reduced.

• Stability of VLBI solutions

We investigated the impact of different analysis options on station positions. It turned out

that the station position repeatability is improved up to 10% by applying thermal deformation and advanced troposphere modeling with VMF1 instead of using the NMF mapping

IVS 2007 Annual Report 195
BKG/IGGB Analysis Center Bundesamt f ̈ur Kartographie und Geod ̈asie

function. On the other hand no significant degradation could be detected by using ECMWF

meteorological data instead of measured meteorological information to model the a priori

dry hydrostatic zenith delay.

• Singular Value Decomposition

At IGGB the development of a regression diagnostics tool has been completed which helps to

analyze the design matrix of a VLBI adjustment by so-called singular value decomposition.

With this tool observing schedules of one-hour Intensive sessions can be analyzed. In order

to find (groups of) important and less important (and thus negligible) observations, so-called

cluster analysis methods are used. The background and first results have been published in

a Ph.D. thesis [7].

4. Personnel

Table 1. Personnel at BKG/IGGB Analysis Center

Thomas Artz IGGB ++49-228-733563 thomas.artz@uni-bonn.de

Sarah B ̈ockmann IGGB ++49-228-733563 boeckmann@uni-bonn.de

Gerald Engelhardt BKG ++49-341-5634438 gerald.engelhardt@bkg.bund.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

Markus Vennebusch IGGB ++49-228-733565 vennebusch@uni-bonn.de

Reiner Wojdziak BKG ++49-341-5634286 reiner.wojdziak@bkg.bund.de

References

[1] GSFC, NASA (2007): Release of Mark 5 VLBI Analysis Software Calc/Solve from October 10, 2007

(web reference: http://vlbi.gsfc.nasa.gov/solve).

[2] VMF1 (2007): (http://mars.hg.tuwien.ac.at/ ̃ecmwf1).

[3] VLBI antenna axis offsets 2007: (http://vlbi.geod.uni-bonn.de/IVS-AC/data/axis-offsets.txt).

[4] VTRF2005: (http://vlbi.geod.uni-bonn.de/IVS-AC/index.html).

[5] ICRF-Ext.1 (http://hpiers.obspm.fr/webiers/results/Icrf).

[6] Engelhardt G., Thorandt V. (2006): First steps to Investigate Long-Term Stability of Radio Sources in

VLBI Analysis. In: IVS General Meeting Proceedings 2006, Concepcion, Chile, edited by D. Behrend

and K.D. Baver, NASA/CP-2006-214140, p.281-285.

[7] Vennebusch M.; Singular value decomposition and cluster analysis as regression diagnostics tools in

geodetic VLBI; Ph.D thesis, Institute of Geodesy and Geoinformation Bonn, 2007, in press; electronic

document: http://hss.ulb.uni-bonn.de/diss online/landw fak/2007/vennebusch markus

196 IVS 2007 Annual Report
NASA Goddard Space Flight Center GSFC Analysis Center

GSFC VLBI Analysis Center

David Gordon, Chopo Ma, Dan MacMillan, Leonid Petrov, John Gipson, Karen Baver

Abstract

This report presents the activities of the GSFC VLBI Analysis Center during 2007. The GSFC

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 aimed at improving the VLBI technique.

2. Activities

2.1. Analysis Activities

The GSFC analysis group routinely analyzes all IVS sessions using the Calc/Solve system, and

performs the AIPS fringe fitting 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, NEOS INT01,

and INT03 sessions. During 2007, the group processed and analyzed 164 24-hr (54 R1, 53 R4,

6 RDV, 1 R&D, 2 T2, 6 CRF, 10 CRDS, 2 CRMS, 6 EURO, 2 OHIG, 2 APSG, 6 E3, and 14

JADE) sessions and 344 1-hr UT1 (230 NEOS INT01, 97 INT02, and 17 INT03) sessions. We

also submitted updated EOP files and daily Sinex solution files for all IVS sessions to the IVS

Data Centers immediately following analysis. The group also generated a new list of axis offsets

and a file of cable cal signs for the IVS. The GSFC Analysis Center maintains a Web site at

http://lupus.gsfc.nasa.gov/, where the latest solutions and velocity plots can be found.

2.2. Support Activities

The GSFC VLBI Analysis Center has provided a source position service as part of the RDV

program since 1997. Observations of 63 requested sources were made in 2007 for members of the

astronomy/astrometry community, and precise positions were obtained where possible.

2.3. Research Activities

The GSFC Analysis Center performs ongoing research aimed at improving the VLBI technique.

Several of these research activities are described below:

• Station Dependent Correlations: The group continued studying the effect of applying station

dependent noise. Best results were achieved when ∼10 psec of correlated atmosphere noise

due to atmosphere mismodeling was applied.

IVS 2007 Annual Report 197
GSFC Analysis Center NASA Goddard Space Flight Center

• Source Imaging and Source Selection: A major effort was undertaken to collect and make

available all existing maps of geodetic and non-geodetic VLBI radio sources. Using images

and visibility plots, all sources were evaluated concerning their suitability as geodetic sources,

and a new list of geodetic sources was proposed. The new list rejects many of the old geodetic

sources based on structure and resolution effects.

• ICRF2 Preparation: A source position time series file was generated and studied. For each

source, the right ascension and declination position WRMS’s were computed. Possible methods for selecting the best set of defining sources were studied.

• MK-VLBA Earthquake: A 6.7 magnitude earthquake occurred near the MK-VLBA site on

15 Oct, 2006. Careful evaluation of the data indicates an episodic displacement of (-8, -10,

+1) mm at MK-VLBA in its Up, East, and North components.

• Higher Frequency CRF: Members of the analysis group continued working with associates

at JPL, USNO, NRAO, and Bordeaux Observatory to extend the celestial reference frame

to higher frequencies by using the VLBA at K and Q bands (∼24 and ∼43 GHz). The

primary goals are to build up a reference frame for use in planetary spacecraft navigation

at Ka band (∼33 GHz), and to build a reference frame less affected by source structure and

potentially more precise than the current X/S frame. One K band session was observed in

2007, concentrating on weaker sources and ecliptic sources. To date, the group has conducted

10 VLBA sessions and developed a catalog of 267 sources at K-band and 132 sources at Qband, with sub-mas positions. Software was developed to insert ionosphere delay corrections

into the databases using GPS ionosphere maps. When these ionosphere corrections are

applied, an approximately linear bias in declination positions compared to X/S positions is

cut in half. Future work will concentrate on observing weaker sources and on densifying the

catalog along the ecliptic and in the regions needed for several upcoming Mars missions.

• Source Monitoring: We continued the source monitoring program which began on February

1, 2004. The goals of this program are to observe all geodetic catalog sources at least 12 times

per 12 month period and sources in the ICRF at least 2 times per 12 month period. This

is done by including the sources which have not met their targets in the weekly R1s. The

maximum number of monitored sources in the R1s is restricted to 10. In 2006 we modified

the use of the RDVs in the monitoring program. Our goal is to periodically observe all the

monitored sources in the RDV sessions with a sufficient number of observations to image

each source. For the geodetic sources our target is 6 times in any two year period, and

for the other sources in the monitoring program at least once per year. We developed a

MySQL database to track which sources and stations appear in each session. This database

is updated whenever 1) a schedule is posted to IVS; 2) the GSFC group analyzes and posts

a database; 3) the master file is updated. For each source and station, the database contains

information about how many observations were scheduled, how many were correlated, and

how many were used in the solution. It also contains information about the fit of the solution.

In late 2007 we converted one of our machines from an HP machine to a Linux machine. In

the process one of the scripts involved in updating the database stopped working. Because

of this the source monitoring program did not work as planned during the last few months

of 2007 and the first few months of 2008. This error has subsequently been fixed.

• Simulations: We continued work on simulations of the performance of networks of VLBI2010

antennas. Our investigation uses a Monte Carlo procedure to simulate the performance of

198 IVS 2007 Annual Report
NASA Goddard Space Flight Center GSFC Analysis Center

different antenna networks and different antenna specifications, where a critical specification

is the antenna slew rate. Baseline length and vertical precision (scatter of simulation estimates) are improved as azimuthal antenna slew rates increase up to about 6 deg/sec but not

significantly for higher rates. Precision of scale and EOP improves by a factor of 1.5 to 2 as

network size increases from 8 to 32 sites.

• Reference Frame Scale: We investigated the systematic effects that contribute to bias and

annual variation of the VLBI reference frame scale. The largest effects are antenna thermal

deformation, loading, and atmosphere modeling, which explain about 0.35 ppb of the observed annual variation of about 0.5 ppb. Most of the scale bias between SLR and VLBI in

the recent ITRF2005 combination was explained.

2.4. Software Development

The GSFC group develops and maintains the Calc/Solve analysis system. Calc/Solve is a

package of approximately 120 programs and 1.2 million lines of code. Several updates were released

during 2007.

3. Staff

Members of the analysis group and their areas of activity include: Dr. Chopo Ma (CRF,

TRF, EOP, K/Q reference frame development, IVS representative to the IERS, current chairman

of the IERS directing board, and ICRF2 development); Dr. Dan MacMillan (CRF, TRF, EOP,

mass loading, antenna deformation, apparent proper motion, post-seismic studies, and ICRF2 development); Dr. David Gordon (database analysis, RDV processing and analysis, K/Q reference

frame development, VLBA calibrator surveys, Calc development, and ICRF2 development): Dr.

Leonid Petrov (CRF, TRF, EOP, mass loading analysis, VLBA calibrator surveys, Calc/Solve development, source mapping and monitoring, Linux migration, GEODYN development, and ICRF2

development); Dr. John Gipson (source monitoring, station dependent noise, improved parameter

estimation, and chairman of IVS Working Group 4 on VLBI data structures); and Ms. Karen Baver

(UT1 Intensive session analysis, software development, Linux migration, and Web site development

and maintenance).

4. Future Plans

Plans for the next year include: participation in the development of the ICRF2, continued

source monitoring, revision of the geodetic source catalog, participation in VLBI2010 development

efforts, participation in the development of a new VLBI data structure, publication of a refereed

RDV geodesy paper, participation in additional K/Q observations and high frequency reference

frame development, and performing further research aimed at improving the VLBI technique.

IVS 2007 Annual Report 199
Haystack Observatory Analysis Center MIT Haystack Observatory

MIT Haystack Observatory Analysis Center

Arthur Niell

Abstract

The contributions of Haystack Observatory to the analysis of geodetic VLBI data focus on improvement in the accuracy of the estimation of atmospheric delays and on the reduction of instrumental errors

through analysis. In 2007 most of the effort was related to evaluating error sources for the proposed

VLBI2010 system, primarily regarding the sensitivity and performance of the broadband development

prototype hardware that has been installed on the MV-3 antenna at GGAO. Since atmosphere delay error continues to be a significant source of geodetic error, a potential method to improve the

measurement of wet delay by Water Vapor Radiometer was investigated and is reported here.

1. Geodetic Research at the Haystack Observatory

The MIT Haystack Observatory is located approximately 50 km northwest of Boston, Massachusetts. Geodetic analysis activities are directed primarily towards improving the accuracy of

geodetic VLBI results, especially through the reduction of errors due to the atmosphere and to

instrumentation. This work, along with operation of the geodetic VLBI correlator and with support of operations at the Westford, GGAO, Fortaleza, and Kokee Park VLBI sites, is supported

by NASA through a contract from the Goddard Space Flight Center.

2. Possible Improvement in the Accuracy of Measurements of Atmosphere Wet

Delay by Water Vapor Radiometer

Historically, comparisons of zenith wet delay (ZWD) as measured by water vapor radiometers

and as estimated from VLBI observations have shown differences of about 1 cm that vary over

hours, even though the shorter term variations may be similar. No alternative to the traditional

calibration of WVR zenith wet delays through the use of radiosondes has been able to reduce or

remove this characteristic difference.

A water vapor radiometer (WVR), when accurately calibrated, measures the brightness temperature of the atmosphere at one or more frequencies. The VLBI observables are delays. For a

WVR to be used directly in the estimation of geodetic parameters the WVR brightness temperatures near the time of the VLBI observation must be related to delay. This has traditionally been

achieved by using several weeks to several months of radiosonde data taken at a site of similar

atmospheric conditions as that where the WVR is used in order to develop a set of regression

coefficients between the brightness temperature and delay. Since the relation between brightness

temperature and delay is not unique (the same delay can be produced by many distributions of atmospheric water vapor and temperature), there is generally a much larger uncertainty in the delay

than would be obtained if the atmospheric distribution were known at the time of the observation.

A possible alternative is to use a Numerical Weather Model to obtain the relation between

brightness temperature as measured by a WVR and the corresponding delay that would be produced by the same atmosphere. The proposal is that the NWM forecasts, while not providing

delays or brightness temperatures that are accurate enough to be used directly in geodetic estimation, do provide the ratio of brightness temperature to delay with sufficient accuracy to add

information. The WVR measurements in themselves will provide the temporal variation of bright200 IVS 2007 Annual Report
MIT Haystack Observatory Haystack Observatory Analysis Center

ness temperature and thus, through the scaling, will provide the temporal variation of the zenith

delay. The VLBI measurements can then be used to estimate the offset, and, if necessary, a further scaling factor. By using the WVR data for the temporal variability, as few as one or two

parameters might be estimated for the atmosphere within a 24 hour period, rather than from 24

values to more than 100. As long as the number of parameters is considerably smaller than would

be required by the VLBI/GPS data alone, the geodetic results should be improved.

To evaluate this proposal, twelve hour forecasts were made using the MM5 Numerical Weather

Model with a finest horizontal grid spacing of three kilometers. (The MM5 calculations were done

by Mark Leidner of AER, Inc.) The WVR measurements were made at Kokee during CONT02 in

October 2002 using a Radiometrics 1100.

The brightness temperatures and derived zenith wet delays, interpolated to the times of the

VLBI observations at Kokee are shown in Figure 1. Periods of rain are seen as large increases in

brightness temperature.

The MM5 forecasts were initiated every 6 hours and run for 12 hours. Pressure level humidities

and temperatures for the last six hours of each forecast were used to calculate zenith wet delays

and brightness temperatures at the times of the VLBI observations. The ratio of ZWD to 23 GHz

brightness temperature was used to scale the values of 23 GHz brightness temperature measured

by the WVR. The values of ZWD obtained the four ways are shown in Figure 2.

Two periods without rain were identified: Oct 22-23 and Oct 26-27. For each of these periods

two differences are displayed in Figures 3 and 4: a) the uncorrected WVR ZWD minus ZWD

estimated from VLBI, and b) the WVR ZWD obtained by scaling with MM5 minus ZWD estimated

from VLBI. The anticipated result was that the biases would be reduced by using the MM5

scaling since it more closely represents the distribution of water vapor at the time of the WVR

measurements than the time-averaged retrieval coefficients obtained from the radiosonde data. In

fact the biases are reduced for both periods, though not to a negligible value. In the first period

the median difference is reduced from 16 mm to 7 mm. For the second period the change is from

13.2 mm to 11.7 mm, but in fact the bias increases for much of the second day.

While the results are promising, the WVR-VLBI difference is not consistently reduced. Potential sources of the remaining error are lack of accuracy of the MM5 forecasts, errors in the

calibration of the WVR brightness temperatures, and incorrect calculation of brightness temperatures from the MM5 forecast values of humidity and temperature.

3. Acknowledgements

I thank Mark Leidner for setting up and running MM5, Wolfgang Schlueter of BKG for providing the WVR for use at Kokee, and Walter Schwartz of BKG for running and maintaining the

Kokee WVR and for processing data.

IVS 2007 Annual Report 201
Haystack Observatory Analysis Center MIT Haystack Observatory

22 24 26 28 30 32 0

50

100

150

200

2002 October

interpolated zenith delay (mm)

Kokee − Radiometrics 1100 W43

interpolated ZWD (mm)

TB 23 GHz

TB 31 GHz

Figure 1. From top to bottom: Zenith Wet Delay (black), brightness temperature at 23 GHz (blue), and

brightness temperature at 31 GHz (red) for Kokee during CONT02. The ZWDs are interpolated to the

time of the VLBI observations.

15 20 25 30 0

100

200

300

400

500

600

2002 October

delay(mm)

Kokee − Radiometrics 1100 W43

WVR 1100

ZWD_tb2d

VLBI

ZWD_mm5

Figure 2. Zenith wet delays for Kokee during CONT02 at the times of the VLBI observations: red cross:

as measured by the WVR; black dot (begins on Oct 22) - as calculated from the WVR value of brightness

temperature at 23 GHz, scaled by the ratio of delay to brightness temperature from the MM5 forecasts;

blue cross - as estimated from VLBI; green dot (begins on Oct 16) - as calculated directly from the MM5

pressure level values of humidity and temperature.

202 IVS 2007 Annual Report
MIT Haystack Observatory Haystack Observatory Analysis Center

22 22.5 23 23.5 24 −20

−10

0

10

20

30

40

2002 October

ZWD difference (mm)

Kokee − Radiometrics 1100 W43

WVR−VLBI

TB2D−VLBI

Figure 3. The differences in ZWD derived from WVR 23 GHz brightness temperature with respect to the

VLBI estimates for Oct 22-23. red cross - WVR ZWD using radiosonde-derived regression coefficients; blue

line - WVR ZWD using MM5 Numerical Weather Model forecast ratios of delay to brightness temperature.

26 26.5 27 27.5 28 −20

−10

0

10

20

30

40

2002 October

ZWD difference (mm)

Kokee − Radiometrics 1100 W43

WVR−VLBI

TB2D−VLBI

Figure 4. Same as for Figure 3 except for Oct 26-27.

IVS 2007 Annual Report 203
IAA Analysis Center Institute of Applied Astronomy of Russian Academy of Sciences (IAA)

IAA VLBI Analysis Center Report 2007

Elena Skurikhina, Sergey Kurdubov, Vadim Gubanov, George Krasinsky

Abstract

This report presents an overview of IAA VLBI Analysis Center activities during 2007 and the plans

for the coming year. The main directions of IAA AC activities are: daily SINEX file generation on a

regular basis for IVS-R1 and IVS-R4 sessions; TRF/CRF estimation from global VLBI data analysis;

routine computations of Earth orientation parameters (EOP) for submission to IERS; baseline length

and tropospheric parameters from 24-h sessions; UT1-UTC from IVS Intensive sessions; time series of

source position calculation and analysis at the scope of the IERS/IVS Working Group on the Second

Realization of the ICRF; EOP, UT1-UTC, and station position estimation from domestic observation

programs; software development, and NGS-file generation.

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 submits to IVS products

such as daily SINEX files, TRF, CRF, rapid and long-term series of EOP, baseline length, and

tropospheric parameters. Source position time series have been calculated and have been analyzed

using the covariance function technique as part of the efforts of the IERS/IVS Working Group on

the Second Realization of the ICRF. EOP, UT1-UTC, and station positions were estimated from

domestic observation programs RU-E and RU-U. The QUASAR software was further developed.

The IAA AC performs NGS-file generation.

2. Component Description

The IAA AC performs data processing of all kinds of VLBI observation sessions.

For VLBI data analysis we use QUASAR and OCCAM/GROSS software. All reductions are in

agreement with the IERS Conventions (2003). Both sets of software use NGS-files as input data.

The IAA AC contributes to all IVS products: daily SINEX-files for EOPS and EOPS-rates

and station position estimations, TRF, CRF, baseline length, and tropospheric parameters.

QUASAR and OCCAM/GROSS software is supported and developed at the IAA AC.

IVS NGS-files are generated on a regular basis in automatic mode.

3. Staff

– Vadim Gubanov, Prof.: development of the QUASAR software, development of the methods

of stochastic parameter estimation.

– Sergey Kurdubov, scientific reseacher: development of the QUASAR software, global solution

and DSNX-file calculation.

– Elena Skurikhina, Dr.: VLBI data processing, OCCAM/GROSS software development.

– George Krasinsky, Prof.: development of new Precession-Nutation Theory based on numerical

integration of refined differential equations of the Earth rotation.

204 IVS 2007 Annual Report
Institute of Applied Astronomy of Russian Academy of Sciences (IAA) IAA Analysis Center

4. Current Status and Activities

• Software development for VLBI processing

The QUASAR software is being developed to provide contributions to IVS products. The

software is able to calculate all types of IVS products. The capability of SINEX-file generation

for IVS-Intensive sessions was added.

• Global solution

In 2007 two global solutions (iaa2007a and iaa2007b) [1, 3] were calculated using the

QUASAR software and submitted to IVS. For the last solution all available data from 1979

until the end of 2007 were processed. Stochastic signals were estimated by means of the

least-squares collocation technique. The radio source coordinates, station coordinates and

velocities were estimated as global parameters. EOP, WZD (linear trend plus stochastic signal), troposphere gradients, and station clocks (quadratic trend plus stochastic signal) were

estimated as arc parameters for each session.

3,984 24-hour sessions with 5,376,127 delays have been processed. 2,760 global parameters

have been estimated: 963 radio-source positions and the positions and velocities of 129 VLBI

stations (12 with discontinuities).

Transformation parameters between ITRF2005 and catalogues obtained for two epochs are

listed in Table 1. The residuals are 6 mm for 1997.0 and 8 mm for 2005.0. 38 stations were

used for the calculations.

Table 1. Transformation parameters between ITRF2005 and obtained catalogue for two epochs.

EPOCH T1,mm T2,mm T3,mm D, 10−9 R1,mas R2,mas R3,mas

2005.0 6.4 -4.8 19.2 -1.6 -0.080 0.139 -0.018

1997.0 4.7 -5.3 5.0 -1.6 -.062 -.090 -.005

The mean formal errors of the source catalogues are 0.15 mas for right ascension, and 0.11

mas for declination. The WRMS difference vs. ICRF.Ext2 is 0.2 mas in right ascension and

declination. (For the statistics on differences, a total of 574 common sources observed in

more than 3 sessions and more than 20 times were used).

• Participation in the IERS/IVS Working Group on the Second Realization of the

ICRF

Two time series iaa000b and iaa000c with more than 600 sources were calculated using the

QUASAR software for VLBI data processing. Most available VLBI observations (excluding

DSN and VCS sessions) since August 1979 to May 2007 were used.

Source positions for every source were obtained from single series analysis by fixing the coordinates of all other sources. A priori source positions were used from the ICRF-Ext.2 radio

source position catalogue. Station positions were not estimated for either series. The TRF

was fixed by ITRF2005, and the CRF was fixed by ICRF-Ext.2. The following parameters

were estimated in these solutions: position of one source, EOP (only for iaa000b solution),

WZD (linear trend and stochastic), troposphere gradient (east and north), and station clock

offset (quadratic trend and stochastic).

IVS 2007 Annual Report 205
IAA Analysis Center Institute of Applied Astronomy of Russian Academy of Sciences (IAA)

We analyzed time series using a covariance function technique adopted for equidistant time

series with the aim of exposing more stable sources. The global solutions with different sets

of sources for NNR constraints were obtained. Transformation parameters between obtained

source catalogues were calculated and compared.

• Routine analysis

In March 2007 the IAA AC started generating daily SINEX files for IVS-R1 and IVS-R4

sessions for rapid solution (iaa2007a.snx) and submitted to IVS SINEX files based on all

24-hr experiments of the Quarterly Solution [3].

During 2007 the routine data processing was performed with OCCAM/GROSS software

using Kalman Filter. IAA AC provided the operational processing of the “24h” and Intensive

VLBI sessions. Submitting the results to the IERS and IVS was performed on a regular basis.

Processing of the Intensive sessions is fully automated. The EOP series iaa2007a.eops and

iaa2005a.eopi, the baseline length series iaa2007a.bl, and the troposphere parameter series

iaa2007a.trl were continued. At the moment, the EOPS series contains 3463 estimates of pole

coordinates, UT1, and celestial pole offsets, and the EOPI series contains 5821 estimates of

UT1. Long-time series of station coordinates, baseline lengths, and tropospheric parameters

(ZTD, gradients) were computed with the station position catalog ITRF2005.

• Station position estimation

The station positions of Zelenchukskaya and Badary (Table 2) were calculated in the

ITRF2005 reference frame. A priori values for the velocity components were used from

GPS data analysis in both cases. The station position of Zelenchukskaya was calculated

from the analysis of 76 IVS 24-hour sessions. The station position of Badary was calculated

from 24 domestic (2006–2007) and IVS (2007) sessions. The results are presented in Table 2.

Table 2. Station positions and velocities for Zelenchukskaya and Badary, epoch 2000.0, in ITRF2005

Station Station Position, m Velocity, mm/year

X Y Z Vx Vy Vz

Badary -838200.729 3865751.573 4987670.956 -.0253 0.0002 -.0037

± 0.008 ± 0.008 ± 0.009

Zelenchukskaya 3451207.821 3060375.231 4391914.941 -.0221 .0141 .0089

± 0.014 ± 0.012 ± 0.015

• EOP parameter calculation from domestic QUASAR network observations

The regular determination of Earth orientation parameters with QUASAR VLBI-Network

Svetloe-Zelenchukskaya-Badary using the S2 registration system started in August of 2006 [4].

Correlation is performed at the IAA correlator. The observations are carried out in the

framework of two national programs: 24-hour sessions for the determination of five EOP

parameters at three observatories of Network (RU-E programs) and 8-hour sessions for the

determination of Universal time at the base Zelenchukskaya–Badary observatories (RU-U

programs). Each of these two sessions are carried out twice per month. RMS deviations of

EOP values from IERS05 C04 series obtained from RU-E program are 0.88 mas for X-pole

and 1.0 mas for Y-pole, 34 μs for UT1-UTC and 0.61 mas for Celestial Pole Offsets (for 17

206 IVS 2007 Annual Report
Institute of Applied Astronomy of Russian Academy of Sciences (IAA) IAA Analysis Center

sessions since Aug 2006 till the end of 2007). RMS deviations of the Universal time values

for RU-U program from IERS05 C04 series are 134 μs (for 23 sessions).

• IVS NGS card generation

Operational computation of the NGS cards was continued. NGS cards are computed in

automated mode. IAA archive of VLBI observations and products was supported. At present,

all available X and S databases and NGS cards are stored.

5. Future Plans

• Continue to submit all types of IVS product contributions and start to submit SINEX files

for IVS Intensive sessions.

• Continue investigations of VLBI estimation of EOP, station coordinates, and troposphere

parameters, and comparison with satellite techniques.

• Continue the studies in the frame of the IERS/IVS Working Group on the Second Realization

of the ICRF.

• Further improve algorithms and software for processing VLBI observations.

• Continue to compute and provide to IVS the NGS cards for every 1-hour Intensive session.

References

[1] Gubanov V. S., Kurdubov S.L. On global solution from VLBI observations. IAA Comm., v. 13, 2005,

p.434–439.

[2] Kurdubov S. L. Covariation analysis of stochastic parameters of VLBI observations model. IAA Comm.,

v. 14, 2006, p.138–157.

[3] Kurdubov S. QUASAR software in IAA EOP service: Global Solution and Daily SINEX. In Proceeding

of the 18th European VLBI for Geodesy and Astrometry Working Meeting ed. by Johannes B ̈ohm,

Andrea Pany, and Harald Schuh, GEOWISSENSCHAFTLICHE MITTEILUNGEN, Heft Nr.79, 2007,

pp. 79-82.

[4] Finkelstein A.M., Skurikhina E.A., Surkis I.F., Ipatov A.V., Rahimov I.A., Smolentsev S.G. USE

OF THE QUASAR VLBI NETWORK FOR FUNDAMENTAL TIME-POSITIONING SERVICE 0F

GLONASS, AJ Letters (in print).

IVS 2007 Annual Report 207
IGG Analysis Center Institute of Geodesy and Geophysics/University of Technology, Vienna

Vienna IGG Special Analysis Center Annual Report 2007

Harald Schuh, Johannes Boehm, Sigrid Englich, Robert Heinkelmann,

Paulo Jorge Mendes Cerveira, Andrea Pany, Emine Tanir, Kamil Teke, Sonya Todorova,

Joerg Wresnik

Abstract

In April 2007, the Institute of Geodesy and Geophysics (IGG) of the Vienna University of Technology organized the 18th European VLBI for Geodesy and Astrometry (EVGA) Working Meeting,

the 8th VLBI Analysis Workshop and the 2nd IVS VLBI2010 Working Meeting. 69 scientists from

all over the world (20 countries) came to Vienna to present and discuss results of recent research in

geodetic and astrometric VLBI. Apart from these meetings, the main focus of research in 2007 has

been on VLBI2010: Simulation studies have been carried out with three different software packages:

(1) the Kalman Filter version of OCCAM, (2) the Vienna VLBI Simulation Software (VVSIM), and

(3) a special Precise-Point-Positioning software for VLBI simulations.

1. General Information

The Institute of Geodesy and Geophysics (IGG) is part of the Faculty of Mathematics and

Geoinformation of the Vienna University of Technology. It is divided into three research units,

one of them focusing on advanced geodesy (mathematical and physical geodesy, space geodesy).

Within this research unit, one group (out of four) is dealing with geodetic VLBI.

Figure 1. Members of the VLBI group at IGG and friends at the EGU General Assembly 2007 in Vienna.

From left to right: R. Heinkelmann, R. Weber, K. Teke, G. Bourda, P. Swatschina, E. Tanir, M. Opitz,

S. Englich, J. Wresnik, A. Korbacz, J. Boehm, M. Kalarus, P.J. Mendes Cerveira, H. Schuh, A. Pany, J.

Sokolova, A. Karabatic, V. Broederbauer. Not on the picture: S. Todorova.

208 IVS 2007 Annual Report
Institute of Geodesy and Geophysics/University of Technology, Vienna IGG Analysis Center

2. Staff

Personnel at IGG associated with the IVS Special Analysis Center in Vienna are Harald Schuh

(Head of IGG, Chair of the IVS Directing Board), and nine scientific staff members. Their main

research fields are summarized in Table 1.

Table 1. Staff members ordered by the main focus of research.

Johannes Boehm VLBI2010, OCCAM Least Squares Method (LSM), VVSIM

Andrea Pany VLBI2010, troposphere, turbulence theory

Joerg Wresnik VLBI2010, OCCAM Kalman Filter, scheduling

Kamil Teke Least squares method, elevation cutoff angles

Sigrid Englich Earth orientation, tidal influences

Paulo Jorge Mendes Cerveira Earth orientation, datum definition

Robert Heinkelmann Combination, celestial and terrestrial reference frame

Emine Tanir VLBI intra-technique combination

Sonya Todorova Ionosphere

3. Current Status and Activities

• 18th EVGA Working Meeting

In April 2007, the IGG in Vienna organized the 18th European VLBI for Geodesy and

Astrometry (EVGA) Working Meeting, the 8th VLBI Analysis Workshop and the 2nd IVS

VLBI2010 Working Meeting. 69 scientists from all over the world (20 countries) came to

Vienna to present and discuss results of recent research in geodetic and astrometric VLBI.

Thanks to all participants for contributing to these events.

• Modification of the VLBI software package OCCAM

Together with Oleg Titov (Geoscience Australia), chairman of the ‘OCCAM Group’, and

Volker Tesmer (Deutsches Geod ̈atisches Forschungsinstitut, Germany), IGG is involved in

the development of the OCCAM software (Titov et al., 2004 [5]). In 2007 the tidal part

of atmosphere loading corrections (Petrov and Boy, 2004 [4]) was implemented, and global

solutions were run to investigate its influence on geodetic parameters.

• VLBI2010

A Precise-Point-Positioning (PPP) simulator has been developed which uses simulated delay

observables consisting of tropospheric wet delays, stochastic errors of station clocks, and

thermal noise of VLBI antennas. Different parameterizations of wet zenith delays including

gradients and combinations of spherical harmonics with different estimation intervals and

constraints were tested (Pany et al., 2007 [3]). Performing a PPP for all stations of a VLBI

schedule allows the comparison of different VLBI2010 schedules as well as comparisons with

OCCAM results (Wresnik et al., 2007 [6]). VLBI2010 slew rate studies have been performed,

and they indicate that more investigations need to be done into scheduling strategies.

• Troposphere

The combination of long time series of wet zenith delays from various IVS ACs has been

IVS 2007 Annual Report 209
IGG Analysis Center Institute of Geodesy and Geophysics/University of Technology, Vienna

continued and described by Heinkelmann et al. (2007a [1]). Additionally, climatic trends

have been determined from long time series of wet zenith delays and compared to results

from GPS and to values from numerical weather models (Heinkelmann et al., 2007 [2]).

• Celestial Reference frame

Together with guest scientist MSc Julia Sokolova from the Russian Academy of Sciences’

Pulkovo Observatory who stayed in Vienna from March to August 2007, comparisons and

investigations into the CRF determination were carried out within the IERS/IVS Working

Group on the Second Realization of the International Celestial Reference Frame (ICRF2)).

• Earth rotation

ERP long time series were computed with different temporal resolution from VLBI observations from 1984 to 2007 with the software package OCCAM 6.1. Short period variations (5

days to 1 year) in universal time induced by zonal tides were derived from UT1-UTC series

with daily resolution (i.e. one estimate per 24 hour session). High-frequency (hourly) polar

motion and UT1-UTC variations were estimated for the CONT05 campaign to study the

effects of diurnal and semi-diurnal ocean tides on Earth rotation. A theoretical study was

carried out to evaluate the benefit of combining VLBI, ringlaser and gravity (from superconducting gravimeters) observations for sub-diurnal Earth rotation parameters. The formulas

relating ringlaser and superconducting gravimeter parameterization to VLBI parameterization were presented. The intricacies of geodetic versus geophysical Earth rotation were

investigated, and a complete geometric interpretation of the Earth rotation vector was given

from the non-linearized skew-symmetric tensor w.r.t. the normalized vector of the so-called

celestial intermediate pole (CIP), ignoring precession-nutation of the CIP (Figure 2).

Figure 2. Earth rotation: Theoretical investigations have been carried out to identify the geophysical Earth

rotation vector in the terrestrial and celestial reference frame.

• Datum definition

The impact on geodetic parameters was examined using several options for getting rid of the

datum deficiency in VLBI analysis. Such options can be minimal conditions or constraints,

which can be related by similarity transformations.

210 IVS 2007 Annual Report
Institute of Geodesy and Geophysics/University of Technology, Vienna IGG Analysis Center

• Solid Earth tides

For the displacement due to solid Earth tides, the IERS Conventions 2003 recommend several

corrections to nominal values. One of these corrections is the in-phase contribution by using

the real Love and Shida numbers h3 and l3 at all degree-3 tides, where only the contribution

of the moon is relevant. Using realistic station and source catalogues, VLBI simulations

of group time delays were calculated, with a white noise going up to 2 cm and taking into

account the solid Earth tides displacement. The goal was to check whether the degree-3

Love and Shida numbers are unambiguously determinable from VLBI observations w.r.t.

time span and number of observables.

4. Future Plans

For the year 2008 the IVS Special Analysis Center at IGG plans to continue all investigations

mentioned above. However, special emphasis will certainly be put on the simulation studies for

VLBI2010 and on research into all aspects of Earth rotation, including its observation with VLBI.

5. Acknowledgements

We are very grateful to the Austrian Science Fund (FWF) for supporting our research projects

P16992-N10 (‘VLBI for climate studies’) and P18404-N10 (‘VLBI2010’). We also acknowledge the

Austrian Academy of Sciences for funding project 22353 and the German Research foundation

(DFG) for funding project SPEED (SCHU 1103/3-1).

References

[1] Heinkelmann, R., J. Boehm, H. Schuh, S. Bolotin, G. Engelhardt, D.S. MacMillan, M. Negusini, E.

Skurikhina, V. Tesmer, O. Titov, Combination of long time-series of troposphere zenith delays observed

by VLBI, Journal of Geodesy, Volume 81, Issues 6-8, pp. 483-501, 2007.

[2] Heinkelmann, R., M. Schmidt, J. Boehm, H. Schuh Determination of water vapor trends from VLBI

observations, Osterreichische Zeitschrift f ̈ur Vermessung und Geoinfor  ̈ mation vgi, Volume 2/2007, ISSN

0029-9650, pp. 73-79, 2007.

[3] Pany, A., J. Wresnik, J. Boehm, H. Schuh, Optimum modeling of troposphere and clock parameters in

VLBI, Proceedings of the 18th European VLBI for Geodesy and Astrometry Working Meeting, 12-13

April 2007, edited by J. Boehm, A. Pany, and H. Schuh, Geowissenschaftliche Mitteilungen, Heft Nr.

79, Schriftenreihe der Studienrichtung Vermessung und Geoinformation, Technische Universitaet Wien,

ISSN 1811-8380, 2007

[4] Petrov, L., J.-P. Boy, Study of the atmospheric pressure loading signal in very long baseline interferometry observations, J. Geophys. Res., Vol. 109, B03405, 2004.

[5] Titov, O., V. Tesmer, J. Boehm, OCCAM v. 6.0 software for VLBI data analysis, in N.R. Vandenberg

and K.D. Baver (eds.): Proceedings of the 3rd IVS General Meeting, Ottawa, Canada, 2004.

[6] Wresnik, J., J. Boehm, H. Schuh, Monte Carlo Simulations for VLBI2010, Proceedings of the 18th European VLBI for Geodesy and Astrometry Working Meeting, 12-13 April 2007, edited by J. Boehm, A.

Pany, and H. Schuh, Geowissenschaftliche Mitteilungen, Heft Nr. 79, Schriftenreihe der Studienrichtung

Vermessung und Geoinformation, Technische Universitaet Wien, ISSN 1811-8380, 2007

IVS 2007 Annual Report 211
Italy INAF Analysis Center Istituto di Radioastronomia–Bologna

Italy INAF Analysis Center Report

M. Negusini, P. Sarti, S. Montaguti, C. Abbondanza

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 Radioastronomy which is part of

the National Institute of Astrophysics. IRA runs the observatories of Medicina and Noto, where two

32m VLBI AZ-EL telescopes are situated. This report contains the AC VLBI data analysis activity

and shortly outlines the investigations carried out in Medicina and Noto concerning gravitational

deformations of the VLBI telescopes.

1. Current Status and Activity

Terrestrial surveying of VLBI telescope structures continued in 2007. A complete survey of

the Medicina VLBI telescope was performed with the aim of determining a new estimate of the

GPS-VLBI eccentricity and of determining the kinematic pattern of the S/X receivers located in

the primary focus. The latter survey, with the same purpose, has been performed at Noto, too.

These data are going to be combined with the laser scanning surveys performed in 2005, and they

will also be compared to the results that are being obtained using a Finite Element Model of the

antennas. The ultimate purpose is to determine the structural deformations caused by gravity

during VLBI observations and to determine how and to what extent the reference points of the

instruments are affected. Comparisons between the different approaches do show encouraging

agreement and will probably supply interesting results concerning the possibility of determining

an elevation dependent signal path variation model.

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 2007, we stored all the 1999—2007 databases available on the IVS data

centers. All the databases were processed and saved with the best selection of parameters for the

final arc solutions. Moreover, because of the new server, all the missing databases were downloaded

from the IVS data centers in order to complete the IRA catalogue. In the meantime, databases

already analyzed and archived on HP workstations were copied to the Linux workstation and

analyzed in order to create new Mark 5 Solve superfiles for global solutions.

Our Analysis Center has participated in the IVS TROP Project on Tropospheric Parameters

since the beginning of the activities. Tropospheric parameters (wet and total zenith delay, horizontal gradients) of all IVS-R1 and IVS-R4 24-hour VLBI sessions were regularly submitted in form

of SINEX files. During the past year, due to several problems, we did not regularly submit results,

but we continued our analysis in order to submit new Mark 5 solutions. We have computed long

time series of troposphere parameters using all VLBI sessions available on our catalogue in order

to estimate the variations over time of the content of water vapor in the atmosphere.

212 IVS 2007 Annual Report
Istituto di Radioastronomia–Bologna Italy INAF Analysis Center

3. Outlook

For the time being, our catalogue finally contains all available experiments. In 2008, using

our new Linux workstation and the up-to-date Mark 5 Calc/Solve software, we plan to analyze all

available databases, thus completing the catalogue. The regular submission of INAF tropospheric

parameters to the IVS data centers will resume as soon as possible.

IVS 2007 Annual Report 213
JPL Analysis Center Jet Propulsion Laboratory, California Institute of Technology

JPL VLBI Analysis Center Report for 2007

Chris Jacobs

Abstract

This report describes the activities of the JPL VLBI analysis center for the year 2007. We continue

to do celestial reference frame, terrestrial reference frame, earth orientation, and spacecraft navigation

work using the VLBI technique. There are several areas of our work that are undergoing active

development. In 2007, an important development was the effort to move earth orientation and reference

frame work to Mark 5 recording and software correlation. Our international collaboration to build

celestial frames at K (24 GHz) and Q-bands (43 GHz) has matured to near a part-per-billion accuracy

as has our in-house work to build a reference at X/Ka-bands (8.4/32 GHz). We are also studying the

use of arrays for spacecraft tracking.

1. General Information

The Jet Propulsion Laboratory (JPL) analysis center is located in Pasadena, California. Like

the rest of JPL, the center is operated by the California Institute of Technology under contract to

NASA. JPL has had a VLBI analysis group since about 1970. Our work is focussed on supporting

spacecraft navigation. This includes several components:

1. Celestial Reference Frame (CRF) and Terrestrial Reference Frame (TRF) are efforts which

provide infrastructure to support spacecraft navigation and Earth orientation measurements.

2. Time and Earth Motion Precision Observations (TEMPO) 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 combined product is used to provide Earth orientation for spacecraft

navigation use.

3. Delta differenced one-way range (∆DOR) is a differential VLBI technique which 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.

3. ∆VLBI phase referencing using the VLBA to measure spacecraft positions.

2. Technical Capabilities

The JPL analysis center acquires its own data and supplements it with data from other centers.

The data we acquire is taken using NASA’s Deep Space Network (DSN).

1. Antennas: Most of our work uses 34m 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 (see Figure

214 IVS 2007 Annual Report
Jet Propulsion Laboratory, California Institute of Technology JPL Analysis Center

1) which has been the most often used set of 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 70m network (DSS 14, DSS

43, DSS 63). Typical X-band system temperatures are 35K on the HEF antennas. The 70m

and BWGs are about 20K. Antenna efficiencies are typically well above 50% at X-band.

Figure 1. This figure shows the three high-efficiency antennas in the subnet: Goldstone is in the center;

Robledo, Spain is on the lower left; and Tidbinbilla, Australia is on the lower right. These antennas were

designed to have an optimum efficiency at X-band (8.4 GHz), which was to become the standard downlink

frequency for solar-system exploration. An important secondary objective was to have a reasonable efficiency

at Ka-band (32 GHz) thereby allowing for possible future use at the next highest band allocated for deep

space communications. The subnet was completed in 1986 in time for the Voyager encounter with Uranus.

2. Data acquisition: The DSN sites have Mark 5A VLBI data acquisition systems. Mark IV

tapes will still be supported for a few more months. 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 is later transferred

via network to JPL for correlation with our software correlator.

3. Correlators: The JPL BlockII VLBI correlator handles the TEMPO and CRF correlations

of Mark IV format tapes while the SOFTC software correlator handles Mark 5A format

recordings. The ∆DOR data from the VSR systems are also correlated using the SOFTC

software correlator running on UNIX workstations. The VSRs and the software correlator

have also been used for connected element interferometry tests of antenna arraying concepts.

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

IVS 2007 Annual Report 215
JPL Analysis Center Jet Propulsion Laboratory, California Institute of Technology

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 with a brief indication of areas of concentration within the VLBI

effort at JPL. 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 our VLBI work.

• Durgadas Bagri: antenna arraying for spacecraft tracking applications

• Jim Border: ∆DOR spacecraft tracking.

• Mike Heflin: CRF and TRF. Maintains MODEST analysis code.

• Chris Jacobs: S/X, K, Q, X/Ka CRFs, and TRF.

• Peter Kroger: ∆DOR spacecraft tracking.

• Gabor Lanyi: VLBA phase referencing, ∆DOR, WVR, K-Q CRF, and TRF.

• Steve Lowe: Software correlator, fringe fitting software.

• Walid Majid: ∆DOR, VLBA phase referencing.

• Chuck Naudet: WVR, Mark IV and Mark 5 support, and K-Q CRF.

• Lyle Skjerve: Field support of VLBI experiments at Goldstone.

• Ojars Sovers: S/X, K, Q, and X/Ka CRFs and TRF. Maintains MODEST analysis code.

• Alan Steppe: TEMPO and TRF.

• L.D. Zhang: S/X, K, and Q CRFs and TEMPO.

4. Current Status and Activities

In order to support the DSN’s move to Ka-band (32 GHz), JPL is leading a collaboration

with Goddard Space Flight Center, the U.S. Naval Observatory, National Radio Astronomical

Observatory, and the Bordeaux Observatory to extend the ICRF to K-band (24 GHz) and Q-band

(43 GHz) (Boboltz et al, 2007; Lanyi et al, 2008). In-house work to build an X/Ka-band CRF is

also currently underway (Jacobs & Sovers, 2007).

The advanced Water Vapor Radiometer (A-WVR) continues to be used in research applications.

This device can calibrate water vapor induced delays to a fractional stability of roughly a few parts

in 1015 over time scales of 2,000 to 10,000 seconds and has demonstrated threefold reduction in

VLBI residuals on time scales of 100 to 1000 seconds (Bar-Sever et al, 2007).

A number of activities are now underway to study the use of antenna arrays for VLBI-based

spacecraft tracking including studies on the potential of the VLBA to make phase referencing

observations of spacecraft positions (Bagri; Bagri et al; Majid & Bagri, 2007).

216 IVS 2007 Annual Report
Jet Propulsion Laboratory, California Institute of Technology JPL Analysis Center

5. Future Plans

In the coming year we expect to move TEMPO and reference frame VLBI completely to Mark

5 recordings. Data rates will gradually be increased to 1 Gbps as resources allow. We plan to

turn our proto-type Ka-band phase calibrator into a set of operational units. Our next generation

fringe fitting program is also expected to come online in the next year. We anticipate refereed

publications on our high frequency celestial reference frame work. On the spacecraft front, we

plan to support a number of missions including the Mars Phoenix lander mission. Research will

continue on techniques for using the VLBA and phase referencing VLBI for spacecraft tracking.

6. Acknowledgements

The work described here was in part performed at the Jet Propulsion Laboratory, California

Institute of Technology, under contract with the National Aeronautics and Space Administration.

References

[1] Bar-Sever, Yoaz E., Christopher S. Jacobs, Stephen Keihm, Gabor E. Lanyi, Charles J. Naudet, Hans

W. Rosenberger, Thomas F. Runge, Alan B. Tanner, & Yvonne Vigue-Rodi, ’Atmospheric Media

Calibration for the Deep Space Network,’ Proc. of the IEEE (Special issue), vol. 95, no. 11, Nov. 2007.

[2] Bagri, D., ‘Same-Beam Tracking with the Proposed DSN Array Using a Calibration Signal from Multiple Sources Simultaneously,’ IPN Progress Report 42-171, 15 Nov. 2007.

http://tmo/progress report/42-171/171F.pdf

[3] Bagri, D.S., J. I. Statman, and M. S. Gatti, ‘Proposed Array-Based Deep Space Network for NASA,’

Proceedings of the IEEE, Special Issue on Technical Advances in Deep Space Communications and

Tracking, vol. 95, no. 10, October 2007.

[4] Boboltz, D., A. Fey, G. E. Lanyi, C.S. Jacobs, C. J. Naudet, L. D. Zhang, C. Ma, D. Gordon, P.

Charlot, E. Fomalont, J. Romney, O. J. Sovers, and B. Geldzahler, ‘VLBI Source Positions at 24 GHz’

Journees, 17 Sep 2007, Paris, France

http://syrte.obspm.fr/journees2007/index.php?page=programme

[5] Jacobs, C.S., and O.J. Sovers, ‘Extending the ICRF to Higher Radio Frequencies: Global Aastrometric

Results at 32/8 GHz,’ 18th European VLBI for Geodesy and Astrometry (EVGA) Working Meeting,

Vienna, Austria, 12-13 Apr 2007, http://www.evga.org/Meetings/evga2007 meeting/s4-3.pdf

[6] Jacobs, C.S., and O.J. Sovers, ‘Extending the ICRF to Higher Radio Frequencies: Global Aastrometric

Results at 32/8 GHz,’ AAS, session 021.01, Honolulu, Hawaii, 28-29 May 2007,

http://www.aas.org/publications/baas/

[7] Lanyi G., D. Bagri and J. Border, ‘Angular Position Determination of Spacecraft by Radio Interferometry,’ Proc IEEE, Vol. 95, No. 11, Nov. 2007, p 2193.

[8] Lanyi, G. E., D. Boboltz, P. Charlot, A. Fey, E. Fomalont, B. Geldzahler, D. Gordon, C.S. Jacobs, C.

Ma, C. J. Naudet, J. Romney, O. J. Sovers, and L. D. Zhang, ‘Astrometry from VLBA Observations

at 24 and 43 GHz,’ AJ, 2008, in preparation.

[9] Majid, W., D. Bagri, ‘In-Beam Phase Referencing with the Deep Space Network Array,’ IPN Progress

Report 42-169, 15 May 2007. http://tmo/progress report/42-169/169F.pdf

[10] Majid W., E. Fomalont, D. Bagri, ‘Compactness of Weak Radio Sources at High Frequencies –

Preliminary Results of VLBA Observations,’ presented at VSOP-2 Meeting, Tokyo, Japan, Dec 2007.

IVS 2007 Annual Report 217
Analysis Center at MAO Main Astronomical Observatory, National Academy of Sciences of Ukraine

IVS Analysis Center at Main Astronomical Observatory of

National Academy of Sciences of Ukraine

Sergei Bolotin, Yaroslav Yatskiv, Svitlana Lytvyn

Abstract

This report summarizes the activities of VLBI Analysis Center at the Main Astronomical Observatory of the National Academy of Sciences of Ukraine in 2007.

1. Introduction

The VLBI Analysis Center was established in 1994 by the Main Astronomical Observatory

(MAO) of the National Academy of Sciences of Ukraine (NASU) as a working group of the Department of Space Geodynamics of the MAO. In 1998 the group started its IVS membership as

an IVS Analysis Center. The AC MAO is located in the Central office of the observatory in Kiev.

2. Technical Description

VLBI data analysis at the center is performed on two computers: a Pentium-4 1.9GHz box

with 256 MB RAM and a 160GB HDD, and a Pentium-4 3.4GHz box with 1 GB RAM and two

200 GB HDDs. Both computers are running under the Linux/GNU Operating System.

The Main Astronomical Observatory improved its Internet connection in 2007. Now we have

a 10 Mbps fiber channel with a 256 kbps backup on leased line.

For data analysis we use the software SteelBreeze which was developed at the MAO NASU.

The SteelBreeze software is written in the C++ programming language and uses Qt widget

library. SteelBreeze makes Least Squares estimation of different geodynamical parameters with

the Square Root Information Filter (SRIF) algorithm (see [1]).

The software analyzes VLBI data (time delay) of a single session or a set of multiple sessions.

The time delay is modeled according to the IERS Conventions (2003) [2], as well as by using

additional models (tectonic plate motion, nutation models, wet and hydrostatic zenith delays,

mapping functions, etc). The following parameters are estimated: Earth orientation parameters,

coordinates and velocities of a selected set of stations, coordinates of a selected set of radio sources,

clock function and wet zenith delay.

3. Staff

The VLBI Analysis Center at Main Astronomical Observatory consists of three members:

Yaroslav Yatskiv: Head of the Department of Space Geodynamics; general coordination and

support of activity of the Center.

Sergei Bolotin: Senior research scientist of the Department of Space Geodynamics; responsible

for the software development and data processing.

Svitlana Lytvyn: A Ph.D. student who is involved in the activities of the AC. Her Ph.D. thesis

concerns the stability of VLBI-derived celestial and terrestrial systems.

218 IVS 2007 Annual Report
Main Astronomical Observatory, National Academy of Sciences of Ukraine Analysis Center at MAO

4. Current Status and Activities in 2007

In 2007 we performed regular VLBI data analysis to determine Earth orientation parameters.

“Operational” solutions were produced and submitted to the IVS on a weekly basis. The IERS

Conventions (2003) [2] models have been applied in the analysis. In the solution, coordinates of

stations and Earth orientation parameters are estimated.

Also, this year we continued to participate in the IVS Tropospheric Parameters project. Estimated wet and total zenith delays for each station were submitted to IVS. The analysis procedure

was similar to the one used for the operational solutions.

In the frame of preparing the next ICRF realization, the center produced global CRF solution

mao000a. The catalog is based on the analysis of almost all available dual-band VLBI observations

from 1980.04.11 to 2007.05.07, which are usable for simultaneous determination of TRF, CRF, and

EOP. In total, 5,905,184 observations acquired on 3,548 VLBI sessions were processed. Coordinates

of radio sources, positions of stations and velocities were estimated as global parameters; EOP were

estimated as local parameters; clock function and tropospheric parameters (zenith delay and its

gradients) were treated as stochastic parameters (random walk model). The CRF solution consists

of coordinates of 2,541 radio sources.

For the same set of VLBI sessions time series of radio sources coordinates variations were

estimated. For this solution, mao000b, we applied the results from previous global solution mao000a

for initial coordinates and velocities of stations, source positions, and EOP. Coordinates of radio

sources were estimated as local parameters. Clock functions and tropospheric parameters were

estimated as stochastic parameters (random walk model).

5. Plans for 2008

MAO Analysis Center will continue to take part in operational EOP determination as well as

updating the solutions of TRF and CRF from VLBI analysis of full data set of observations.

The improving of the SteelBreeze software will also be continued next year.

Acknowledgments

The work of our Analysis Center would be impossible without activities of other components

of IVS. We are grateful to all contributors of the Service.

References

[1] Biermann, G.J., 1977, Factorization Methods for Discrete Sequential Estimation, V128, Mathematics

in Science and Engineering Series, Academic Press.

[2] IERS Conventions (2003), IERS Technical Note 32, eds. D.D. McCarthy and G. Petit, Bundesamt f ̈ur

Kartographie und Geod ̈asie, Frankfurt am Main.

IVS 2007 Annual Report 219
NICT Analysis Center Kashima Space Research Center, NICT

Analysis Center at National Institute of Information and

Communications Technology

Thomas Hobiger, Ryuichi Ichikawa, Mamoru Sekido, Hiroshi Takiguchi, Tetsuro Kondo,

Yasuhiro Koyama

Abstract

This report summarizes the activities of the Analysis Center at National Institute of Information

and Communications Technology (NICT) for the year 2007.

1. General Information

The NICT Analysis Center is located in Kashima, Ibaraki, Japan and is operated by the

VLBI group of NICT. Analysis of VLBI experiments and related study fields at NICT are mainly

concentrated on experimental campaigns for developing new techniques such as e-VLBI for realtime EOP determination, prototyping of a compact VLBI system, ionospheric and atmospheric

path delay studies, and differential VLBI (DVLBI) for spacecraft orbit determination. In addition

we analyzed IVS-T2 sessions.

2. Staff

Members who are contributing to the Analysis Center at the NICT are listed below (in alphabetical order):

• HOBIGER Thomas, Postdoctoral fellow of the Japan Society for the Promotion of Science

(JSPS)/Atmospheric and ionosphere research using VLBI and GPS

• ICHIKAWA Ryuichi, Compact VLBI system development and Atmospheric Modeling

• KONDO Tetsuro, Software Correlator

• KOYAMA Yasuhiro, International e-VLBI

• SEKIDO Mamoru, International e-VLBI and VLBI for spacecraft navigation

• TAKIGUCHI Hiroshi, International e-VLBI and loading effects

3. Current Status and Activities

3.1. Ultra-rapid UT1 Experiments

Data transfer via Internet protocols allows to reduce the latency of UT1 measurements obtained

from VLBI. Such experiments, known as e-VLBI, were conducted in cooperation with colleagues

from Mets ̈ahovi, Onsala, Wettzell, and GSI in order to demonstrate that the estimates of UT1 can

be obtained shortly after the last scan has been observed. By the usage of the UDP-based Tsunami

protocol, data were sent to Kashima, converted to K5 format, and handed over to our software

correlator [2] which is operated in distributed computing mode. Thus it was possible to obtain UT1

estimates, which are proven to be as accurate as the IERS Bulletin-A results, already 30 minutes

after the last observation has been made [3]. The experience gained from these experiments is

220 IVS 2007 Annual Report
Kashima Space Research Center, NICT NICT Analysis Center

going to be applied to the weekly intensive VLBI sessions and is expected to improve the latency

and accuracy of the IERS products.

Table 1. e-VLBI sessions for rapid UT1 measurement performed since April 2007. Station codes are as

follows, “Ks”:Kashima34, “Ts”:Tsukuba 32, “On”:Onsala, “Mh”:Mets ̈ahovi, “Wz”:Wettzell.

Date Baseline Data rate UT1-UTC UT1-c04 Error Latency

2007 (Mbps) (ms) (μ sec.) (μ sec.)

03 April Ks – On 256 -69.6044 -38.5 8 –

23 April Ks – On 128 -98.4422 15.0 41 1 h 55 min.

02 May Ks – On 128 -110.0189 -30.4 16 –

18 May Ks – Mh 128 -130.5832 67.5 98 2 h 38 min.

30 May Ks – On 128 -143.2703 -14.7 9 28 min.

31 May Ks – On 128 -143.7011 -83.5 8 –

04 June Ks – On 256 -144.6447 13.1 6 31 min.

14 July Ks-On, Ks-Wz 256 -162.0879 6.2 6 –

Ks – On -162.1017 -7.6 10

Ks – Wz -162.0715 22.6 8

Ts – Wz, On-Ts -162.0674 26.7 8

On – Ts -162.0725 21.6 7

Ts – Wz -162.0585 35.6 5

Ts – Wz(INT2) -162.0974 -3.3 7

15 July Ks – On 256 -162.0186 -30.7 6 –

Ts – Wz(INT2) -162.0017 -13.8 8

25 Oct Ks – On 256 -208.4180 95.8 640 –

26 Nov Ks – On 128 -240.0781 75.8 8 –

256 -240.1118 78.2 16 –

512 -240.1134 82.5 29 –

128 -240.1621 76.9 8 25 min.

128 -240.2628 -2.3 14 27 min

512 -240.3020 -8.8 30 –

3.2. CARAVAN2400

We are currently developing a “Compact Antenna of Radio Astronomy VLBI Adapted for Network” with a 2.4 m diameter dish, which is named CARAVAN2400. A geodetic VLBI experiment

between the CARAVAN2400 and the GSI 32 m antenna at Tsukuba was performed from Jan 31

until Feb 1, 2007. In this experiment, the K5/VSI system was used with a bandwidth of 512 MHz

in order to evaluate the performance of an even smaller VLBI system with a 1.6 diameter. The

obtained results were well consistent with the one from a previous test using the K5/VSSP system.

In addition, another VLBI experiment between Kashima 34 m and Koganei 11 m was performed

on July 19, 2007. At Kashima, a Cs gas-cell atomic frequency standard was used instead of the

hydrogen maser in order to evaluate its capability for geodetic VLBI experiments. Although the

Allan variance of the Cs gas-cell is worse than that of the hydrogen standard by a factor of about

IVS 2007 Annual Report 221
NICT Analysis Center Kashima Space Research Center, NICT

ten, the baseline length results were in quite good agreement with the previous experiment.

3.3. MK3TOOLS

A set of programs, summarized under the name MK3TOOLS, allows the creation of Mark III

databases from post-correlator output without any dependency on CALC/SOLVE libraries [1].

NetCDF files are utilized as intermediate data-storage and either Mark III compatible databases

or NGS files are generated for follow-on analysis (Figure 1). Since all routines can be controlled

from the command-line, MK3TOOLS enables the realization of a processing chain without human

interactions and allows to generate databases for applications with a high demand on low latency

(e.g. e-VLBI). Currently only K5 post-correlation format is supported by MK3TOOLS.

Figure 1. The role of MK3TOOLS between correlator output and analysis

3.4. Differential VLBI for Spacecraft Tracking

Together with JAXA/ISAS, Japan the HAYABUSA satellite has been tracked on March 7th,

2007 with the purpose to test a phased-array tracking system within Japan.

3.5. Kashima Ray-tracing Tools - KARAT

Numerical weather models (NWM) have undergone an improvement of spatial and temporal

resolution which makes it possible to utilize them for the computation of electro-magnetic wave

propagation characteristics. Until now such models have been used to create mapping functions,

which relate slanted observations to vertical ones. In our studies we have tried to handle numerical

weather models to obtain directly the troposphere total slant delays in any arbitrary direction by

ray-tracing methods. Thus a set of programs, subsumed under the name Kashima Ray-Tracing

Tools (KARAT), has been developed which allows to carry out fast and accurate ray-tracing

tasks and output the information in standard formats. All modules are designed to fulfill the

requirements for real-time processing, but are capable to run in post-processing mode as well.

Numerical weather models from the Japanese Meteorological Agency (JMA), covering East Asia

(including Japan, Korea, Taiwan, and parts of Russia and China), can be input directly to KARAT.

222 IVS 2007 Annual Report
Kashima Space Research Center, NICT NICT Analysis Center

First tests using GPS have revealed that more than 99% of total troposphere can be modeled by

KARAT and that only a simple mapping function is needed to account for the remaining symmetric

troposphere delay. Application within VLBI analysis and usage for space-craft tracking is planned

for the near future. Moreover KARAT can be used to simulate/evaluate positioning errors of space

geodetic techniques associated with water vapor inhomogeneities.

3.6. Phase Ambiguity Resolution Within Next-Generation VLBI

Next-Generation VLBI system designs are aiming at one mm global position accuracy. Thus, it

is not only necessary to deploy improved VLBI systems, but also to revise analysis strategies that

take full advantage of the observations taken. With the new systems, it should be feasible to resolve

phase ambiguities directly from post-correlation data, providing roughly an order of magnitude

improvement in precision of the delay observable. As the unknown ambiguities are of integer

nature, it has been investigated how they the can be resolved analytically using algorithms which

have been developed for GNSS applications. Furthermore, it has been shown that other nuisance

parameters can be solved simultaneously with the analytically relevant delay observables. In order

to test this, artificial observations were created using parameters from actual design studies and

these were used to test the developed algorithms.

4. Future Plans

For the year 2008 the plans of the Analysis Center at NICT include:

• Several international and domestic VLBI experiments for real-time EOP determination using

e-VLBI and the K5 system (both VSSP system and PC/VSI system)

• Unattended generation of Mark III databases and automated processing of UT1 experiments

• Differential VLBI experiments for spacecraft tracking and its analysis

• Development of the analysis software for spacecraft positioning using phase delay observables

• Improvement of processing speed and efficiency for the VLBI data correlation using multiprocessor and high speed network

• Implementation of KARAT in a multi-processor/multi-core environment and establishment

of an on-line ray-tracing service

References

[1] Hobiger T., Y. Koyama and T. Kondo, MK3TOOLS & NetCDF - storing VLBI data in a machine

independent array oriented data format, Proceedings of the 18th European VLBI for Geodesy and

Astrometry Working Meeting, Geowissenschaftliche Mittteilungen, Nr. 79, 194–195, 2007.

[2] Kondo T., M. Kimura, Y. Koyama and H. Osaki, Current status of software correlators developed at

Kashima Space Research Center, In: International VLBI Service for Geodesy and Astrometry 2004

General Meeting Proceedings. NASA/CP-2004-212255, 186–190, 2004.

[3] Sekido M., H. Takiguchi, Y. Koyama, T. Kondo, R. Haas, J. Wagner, J. Ritakari, S. Kurihara and K.

Kokado, Ultra-rapid UT1 measurements by e-VLBI, submitted to Earth, Planets and Space, 2008.

IVS 2007 Annual Report 223
Paris Observatory Analysis Center (OPAR) Observatoire de Paris, SYRTE, CNRS/UMR8630

Paris Observatory Analysis Center OPAR: Report on Activities,

January - December 2007

Anne-Marie Gontier, S ́ebastien B. Lambert, Christophe Barache

Abstract

This report summarizes the activities of the VLBI Analysis Center at the Paris Observatory (OPAR)

for calendar year 2007. Quarterly solutions were processed to estimate EOP per session and global

terrestrial and celestial reference frames. Additionally, the analysis center organized the operational

analysis of weekly IVS-R1 and IVS-R4 sessions for regular submission to the IVS (scheduled to start

early 2008). Other activities of the OPAR personnel related to VLBI include two main research topics:

(i) the realization of a stable celestial reference frame (in the frame of the IVS/IERS Working Group

on the “Second Realization of the ICRF”), and (ii) the analysis of VLBI-derived nutation time series

to retrieve deep Earth’s interior parameters.

1. Operational Analysis Status

In 2007, the quarterly solutions for Earth’s orientation parameter, station coordinates and

velocities and radio source coordinates have been submitted regularly to IVS and IERS EOP-PC.

For those solutions, all station and source coordinates are estimated as global parameters except

for poorly observed sources which are treated as arc parameters. The main difference with other

analysis centers’ analysis strategies is that we chose to define the orientation of the celestial frame

by a no-net-rotation with respect to the ICRF-Ext.2 tie to the [1] (further referred to as MFV)

247 stable sources. The last 2007 solution (2007d, see Figure 1) processed 3,643,608 delays and

delay rates in 3,272 sessions. The global postfit rms delay nears 24 ps.

Operational analysis for the production of daily SINEX files has been set up and tested at the

end of the year, in order to participate in the IVS SINEX combination. The regular submission of

SINEX files to the IVS analysis coordinator’s office will begin in early 2008.

The OPAR Web site (http://ivsopar.obspm.fr/) is regularly updated to provide information

and data on the latest processings. In addition, we provide some OPAR products in VOTable

format as defined by the International Virtual Observatory Alliance (IVOA) on the VO-Corner

section of our Web site.

2. Celestial Reference Frame Issues

The production and analysis of time series of radiocenter positions was continued and updated

quarterly in 2007. The times series are available at the IVS data center and the OPAR Web site

(we provide ASCII data files and plots).

In the framework of ICRF2 elaboration, we investigated the time series in terms of time stability.

Our future aim is to derive the best subset of stable radio sources suitable for defining the axes

of the next ICRF. In a study presented at the Journ ́ees Syst`emes de R ́ef ́erence Spatio-Temporels,

in Paris [3], we analyzed the position time series of 521 sources observed in more than 10 sessions

between 1984.0 and 2007.5 (see Figure 2). It appeared that time series are so noisy or sparse that

the only meaningful quantities that can be extracted from the analysis are the weighted rms and

a medium-term irregular pattern (through, e.g., a weighted moving average) for each series. We

applied a very simple selection scheme only playing with the rms and the slope. The selection

224 IVS 2007 Annual Report
Observatoire de Paris, SYRTE, CNRS/UMR8630 Paris Observatory Analysis Center (OPAR)

1985 1990 1995 2000 2005

−1.5

−1

−0.5

0

0.5

1

1.5

δX (mas)

1985 1990 1995 2000 2005

−1.5

−1

−0.5

0

0.5

1

1.5

δY (mas)

Figure 1. Celestial pole offsets from quarterly solution opa2007d.

parameters have been tuned so that the number of elected sources reaches ∼200. Our subset

finally contains 197 sources, of which 32% are part of the 212 ICRF defining sources [6] and 68%

are part of the 247 MFV stable sources. The axis stability of the reference frame defined by the

above-selected sources was then assessed using a four parameter transformation (3 rotation angles

and the tilt parameter dz) between a semi-annual reference frame (defined by the semi-annual

coordinates of the selected radio sources) and the reference catalogue ICRF-Ext.2 [2]. It appears

that our selection of sources leads to a significantly better stability for the reference frame. It is

obvious that this selection must be supplemented by other selections done through other criteria

(e.g., refined algorithms, source compactness), particularly since our selection yields a poor number

of sources in the southern hemisphere.

3. Geophysics Issues

Since VLBI is a major and powerful technique revealing the deep Earth’s interior (along with

seismology and gravimetry), one must ask oneself whether the discussions and achievements about

the new ICRF can lead to an improvement of the VLBI data in a geophysical sense. Remember

that geophysical parameters in the IAU-adopted [7] (referred to as MHB) nutation theory have

been adjusted on VLBI nutation time series. If MHB is powerful, it is obviously because of the

MHB theoretical framework, but also because of a considerable improvement of VLBI data during

the last decade of the XXth century. But, although this theory is very satisfying, challenging

questions still remain, like, e.g., the direct observability of the diurnal wobble associated with the

free inner core nutation, or, at least, a better determination of its resonant period. Answers to

IVS 2007 Annual Report 225
Paris Observatory Analysis Center (OPAR) Observatoire de Paris, SYRTE, CNRS/UMR8630

0 5 10 15 20

−80

−60

−40

−20

0

20

40

60

80

Right Ascension (hr)

Declination (°)

1 mas

−80 −60 −40 −20 0 20 40 60 80

0

50

100

150

Declination

Angle (°)

−80 −60 −40 −20 0 20 40 60 80

0

1

2

3

4

5

Declination

Wrms (mas)

Figure 2. Top: Envelopes of variability (defined as the rms in a given direction) of the 521 radio sources

investigated in this study. Middle: Dependence of the angle of maximal variability on the declination.

Bottom: Dependence of the rms on the declination.

226 IVS 2007 Annual Report
Observatoire de Paris, SYRTE, CNRS/UMR8630 Paris Observatory Analysis Center (OPAR)

these questions are currently partly hidden in the noisy nutation residuals and we have either to

dig out meaningful information from the noise, or to remove the noise by a wise analysis of VLBI

observations at the analysis center level. In the context of the on-going effort to improve the

theoretical modeling of the nutation (see, e.g., the recent computation of the torque on the tidally

redistributed matter by [4], that was partly omitted in the MHB theory), identifying the various

sources of errors in the estimates appears very worthwhile.

Obtaining nutation from VLBI analysis needs to handle correctly the celestial reference frame

so that radio source positional instabilities may not unduly perturb the nutation estimates. In

a study recently accepted for publication in Astronomy & Astrophysics [5], we tried to estimate

the magnitude of these perturbations and to determine their impact on the resonant frequencies

associated with the Earth’s fluid outer and inner cores. We achieved this playing with the constraints that are applied to the radio source positions during a global analysis. We showed that

an additional error of ∼15 μas in the estimates of the 18.6 year nutation spectral component and

decreasing for shorter periods can be produced by the instabilities in the celestial frame. This

leads to an uncertainty of few tenths of day on the fluid outer core resonant period and of 200 on

its quality factor, and an uncertainty of less than 100 days on the inner core resonant period and

100 on its quality factor.

References

[1] Feissel-Vernier, M., Ma, C., Gontier, A.-M., & Barache, C. 2006, A&A, 452, 1107 A&A, 452, 1107

[2] Fey, A.L., Ma, C., Arias, E.F., et al. 2004, AJ, 127, 3587

[3] Gontier, A.-M., & Lambert, S.B. 2007, In: N. Capitaine (Ed.), Proc. Journ ́ees 2007 syst`emes de

r ́ef ́erence spatio-temporels, Observatoire de Paris, in press

[4] Lambert, S.B., & Mathews, P.M. 2006, A&A, 453, 363

[5] Lambert, S.B., Dehant, V., & Gontier, A.-M. 2007, A&A, in press

[6] Ma, C., Arias, E.F., Eubanks, T.M., et al. 1998, AJ, 116, 516

[7] Mathews, P.M., Herring, T.A., & Buffett, B.A. 2002, J. Geophys. Res., 107(B4), 10.1029/2001JB000390

IVS 2007 Annual Report 227
Onsala Space Observatory (OSO) Analysis Center Onsala Space Observatory (OSO)

The IVS Analysis Center at the Onsala Space Observatory

R ̈udiger Haas, Hans-Georg Scherneck, Tobias Nilsson

Abstract

This report briefly summarizes the activities of the IVS Analysis Center at the Onsala Space

Observatory during 2007. Some examples of ongoing work are presented.

1. Introduction

We concentrate on a number of research topics that are relevant for space geodesy and geosciences. These research topics are addressed in connection to data observed with geodetic VLBI

and complementing techniques. As in previous years the main focus was on high-frequency Earth

orientation, loading phenomena, and atmospheric water vapor. Some topics are briefly presented

in the following.

2. hfEOP from VLBI CONT Campaigns

In collaboration with Anna Korbacz from the Space Research Centre of the Polish Academy of

Sciences, we continued our work on high-frequency EOP variations from VLBI CONT campaigns

[1]. Anna stayed at Onsala for 2 months on a stipend provided by the Descartes-Nutation consortium. During her stay we worked on the application of various spectral analysis techniques on

the VLBI CONT data with a focus on the previously detected ter-diurnal signals [2]. One result

of this work is that the possibility that the ter-diurnal signals are caused by the actual VLBI data

analysis could be ruled out with high probability. Another result is that predicted high-frequency

EOP variations based on a recent ocean model with high temporal resolution cannot explain the

detected signals either. Further work on this topic is needed.

3. Ocean Tide and Atmospheric Loading

The automatic ocean tide loading service [3] has been maintained. The transition to a new

computer described previously [1] was successful and resulted in faster processing speed in 2007

as compared to earlier years.

4. Contributions to VLBI2010 Simulations

We contributed to the VLBI2010 simulation work by determining equivalent zenith wet delays

for VLBI2010 simulation schedules [4]. These tropospheric parameters are determined using a

turbulence model [5] together with wind data and tropospheric height scale from a numerical

weather model [6]. The turbulence parameters are determined from high-resolution radiosonde

data, and a global model for turbulence as a function of latitude was developed. Figure 1 gives

an example for these simulations for the Station Ny- ̊Alesund on Spitsbergen, and shows the scale

height, wind speed and direction at the 850 hPa level, and the simulated equivalent wet delay

values for 25 continuous days.

228 IVS 2007 Annual Report
Onsala Space Observatory (OSO) Onsala Space Observatory (OSO) Analysis Center

Figure 1. Example of VLBI2010 simulations of equivalent zenith wet delay values for Ny- ̊Alesund. Shown

are a) wind speed, b) wind direction, c) tropospheric height, and d) simulated equivalent zenith wet delays.

5. Contribution to the IVS TROP Project

The submission of solutions of tropospheric parameters of the R1 and R4 experiments was

interrupted during 2007 due to the transition of the Calc/Solve analysis from an HP system to a

Linux system. We plan to resume participation in this project during 2008.

6. Results from the Fennoscandian-Japanese Ultra-rapid dUT1 Observations

During 2007 we started a collaboration with colleagues at Mets ̈ahovi, Kashima and Tsukuba to

observe dUT1 with very low latency. Several ultra-rapid dUT1 experiments were observed in 2007.

All of them used real-time e-VLBI data transfer from Fennoscandia to Japan and near real-time

data conversion, near real-time or off-line correlation, and preparation of VLBI databases and

data analysis. Figure 2 shows the network constellation with the long east-west baselines that are

well-suited for earth rotation observations. In the best cases dUT1 results were available within 30

minutes after the end of an observing session. We did a post-processing analysis of the experiments

and show in Figure 3 the dUT1 of the Fennoscandian-Japanese experiments together with the final

VLBI dUT1 values provided by the USNO. Time series of dUT1 after subtraction of a linear trend

and the differences between the two series are shown. With the exception of experiments that had

severe technical problems causing loss of observations, e.g. October 2007 and November 2007, the

agreement between the two series is within about 60 μs. Further studies focussing on the role of

scheduling options, data rate, and analysis strategies are ongoing.

IVS 2007 Annual Report 229
Onsala Space Observatory (OSO) Analysis Center Onsala Space Observatory (OSO)

Figure 2. The network configuration for the Fennoscandian-Japanese ultra-rapid dUT1 measurements.

Figure 3. dUT1 values after subrtacting a linear trend. Top: Final UT1 values of the USNO (continuous

line) and results of the Fennoscandian-Japanese ultra-rapid dUT1 experiments (circles). Bottom: The

corresponding differences.

230 IVS 2007 Annual Report
Onsala Space Observatory (OSO) Onsala Space Observatory (OSO) Analysis Center

7. Outlook

The IVS Analysis Center at the Onsala Space Observatory will continue its efforts to work on

specific topics relevant for space geodesy and geosciences.

References

[1] Haas, R., Scherneck, H.-G., Nilsson, T.: The IVS Analysis Center at the Onsala Space Observatory.

In: D. Behrend and K. Baver: International VLBI Service for Geodesy and Astrometry 2006 Annual

Report, NASA/TP-2007-214151, 224–227.

[2] Haas, R: Investigating High-Frequency Earth Orientation Variations with Continuous Geodetic VLBI

Campaigns. In: D. Behrend and K. D. Baver (Eds.): IVS 2006 General Meeting Proceedings,

NASA/CP-2006-214140, 316–319, 2006.

[3] Scherneck, H.-G., and Bos, M.: Ocean Tide and Atmospheric Loading. In: N. R. Vandenberg and

K. D. Baver (Eds.): IVS 2002 General Meeting Proceedings, 205–214, NASA/CP-2002-210002, 2002.

[4] Nilsson, T., Haas, R., Elgered, G.: Simulations of atmospheric path delays using turbulence models. In:

J. B ̈ohm, A. Pany, and H. Schuh: Proceedings of the 18th European VLBI for Geodesy and Astrometry

Working Meeting, Geowissenschaftliche Mitteilungen, Schriftenreihe der Studienrichtung Vermessung

und Geoinformation, Technische Universit ̈at Wien, 79, 175–180.

[5] Nilsson, T., Elgered, G., and Gradinarsky, L.: Characterizing Atmospheric Turbulence and Instrumental Noise Using Two Simultaneously Operating Microwave Radiometers. In: Proc. 9:th Specialist

Meeting on Microwave Radiometry and Remote Sensing Applications, MicroRad 2006, 270–275, 2006.

[6] ERA40: http://data.ecmwf.int/research/era/

IVS 2007 Annual Report 231
PUL Analysis Center Central Astronomical Observatory at Pulkovo of Russian Academy of Sciences

PUL IVS Analysis Center Report 2007

Zinovy Malkin, Julia Sokolova, Natalia Miller

Abstract

The report briefly presents the PUL IVS Analysis Center activities during 2007 and plans for the

coming year. Main topics of investigation in that period were comparison and combination of catalogues

of radio source positions, analysis of VLBI EOP series, analysis of radio source position and zenith

troposphere delay time series.

1. General Information

The PUL IVS Analysis Center was organized in September 2006 and is located at the Central

Astronomical Observatory at Pulkovo of Russian Academy of Sciences (Pulkovo Observatory).

The main topics of our activity are:

• Improvement of the International Celestial Reference Frame (ICRF), including investigations

of radio source catalogues, constructing combined catalogues, investigation of the ICRF

stability, and investigation of radio source position time series.

• Computation and analysis of EOP, station position, baseline length and zenith troposphere

delay time series.

• Investigation of Free Core Nutation (FCN).

• Comparison of VLBI results with other space geodesy techniques.

The PUL AC’s Web page is available at http://www.gao.spb.ru/english/as/ac vlbi/.

2. Scientific Staff

PUL team consists of three scientists:

1. Zinovy Malkin (70%) — team coordinator, computation and analysis of EOP, station coordinates and baseline length, development of algorithms and software for data processing and

analysis;

2. Julia Sokolova (100%) — global data analysis for deriving radio source catalogues and position time series, comparison and combination of radio source catalogues, time series analysis,

development of algorithms and software for CRF studies;

3. Natalia Miller (20%) — investigation of FCN and zenith troposphere delay; application of

new mathematical methods to time series analysis.

3. Activities

The activities of the PUL IVS Analysis Center during 2007 included:

• Investigations in the framework of the IERS/IVS Working Group on the Second Realization

of the ICRF were continued. Main directions of this activity are comparison and combination

of radio source catalogues, computation and investigation of source position time series. The

main results obtained in 2007 are the following.

232 IVS 2007 Annual Report
Central Astronomical Observatory at Pulkovo of Russian Academy of Sciences PUL Analysis Center

– Two combined radio source catalogues have been constructed and investigated [1]. The

first of them provides a stochastic improvement of the current ICRF realization, and

the second one allows us to account also for systematic errors in the ICRF. Comparison

of the celestial pole offsets obtained from the processing of VLBI observations using

ICRF and the combined catalogue has shown improvement of the results. Further

improvement is expected after refining the comparison and combination procedures.

– A new method of assessment of the CRF accuracy based on the scatter analysis of the

celestial pole offset (CPO) time series is proposed [2]. Several scatter indices based

on residual analysis of CPO series with respect to a FCN model and Allan deviation

technique and its extensions, which allow the treatment of unequally weighted and

multidimensional observations, are investigated. Application of these criteria to several

radio source catalogues showed their ability to perform a preliminary assessment of the

quality of the CRF realizations.

– Several radio source catalogues and source position time series from a global analysis

of VLBI data with the OCCAM 6.2 software were calculated using different modes.

Comparison of four lists of reference sources showed significant inconsistencies in source

selection. The impact of radio source instability on celestial pole offset estimates was

investigated. Analysis showed that variations of radio-source coordinates affect the

celestial pole offset estimates (Fig. 1, [6]). These results mainly were obtained during

a 6-month visit of Julia Sokolova at the Institute of Geodesy and Geophysics (IGG),

Vienna in March–August 2007.

– The first version of a new list of the optical characteristics of geodetic radio sources

is compiled. Further development is being performed in cooperation with Geoscience

Australia Analysis Center and Pulkovo optical astronomers.

1990 1995 2000 2005

−2

−1

0

1

2

Year

α (mas)

1990 1995 2000 2005

−0.1

−0.05

0

0.05

0.1

mas

Year

Figure 1. Variations of source 2145+067 positions (left) and differences between two CPO time series (right).

For the first CPO series, all the observations were used. For the second CPO series, the observations of

2145+067 were excluded. Source and station positions were fixed in both cases.

• The IVS combined CPO time series was analyzed using several statistical tools, such as

spectrum analysis, singular spectrum analysis, or wavelet analysis to investigate both trend

and (quasi)periodical components. The results are presented in [4]

• A new VLBI network geometry index, the volume of network, is examined as an indicator of

the quality of the EOP obtained from VLBI observations [5]. It has been shown that both

EOP precision and accuracy can be described by a power law σ = aV b, where V is the volume

IVS 2007 Annual Report 233
PUL Analysis Center Central Astronomical Observatory at Pulkovo of Russian Academy of Sciences

of network, in a wide range of network size from domestic to global VLBI networks. The

dependence found can be used for comparison of results obtained from different observing

programs.

• Several very long and very dense zenith troposphere delay time series provided by the IGG

IVS Special Analysis Center as an IVS troposphere product were analyzed by means of the

method of Singular Spectrum Analysis (SSA) in both one-dimensional and multi-dimensional

modes. The structure of the time series including regular, quasiregular (periodical) and

irregular (trend) components was obtained and investigated. Using SSA allowed us to derive

nonlinear trends in zenith troposphere delay, and also to research the variation of amplitude

and phase of season components with time.

• Regular computation of two refined Free Core Nutation (FCN) time series started in 2006

were continued. They were briefly described in the PUL IVS Analysis Center Report 2006.

More detailed description and comparison with other models are given in [3]

• Development of algorithms and software for data processing and analysis was continued.

• PUL archive of VLBI data and products was originated in the end of 2006. At present,

all available databases and NGS cards have been stored along with main IVS and IERS

products.

• PUL staff members participated in activities of several IVS projects, Working Groups and

Committees.

4. Outlook

Plans for the coming year include:

• Continuation of the IVS related studies.

• Development of algorithms and software used for data processing.

• Support of the PUL archive of data and products.

References

[1] Sokolova Ju., Malkin Z. On comparison and combination of catalogues of radio source positions. Astron.

Astrophys., 2007, 474, No. 2, 665–670.

[2] Malkin Z. J. Geod., On accuracy assessment of celestial reference frame realizations. 2007, DOI:

10.1007/s00190-007-0181-x

[3] Malkin Z.M. Empiric Models of the Earth’s Free Core Nutation. Solar System Research, 2007, 41, No. 6,

492–497.

[4] Malkin Z., Miller N. An analysis of celestial pole offset observations in the free core nutation frequency

band. In: Proc. 18th EVGA Working Meeting, Vienna, Austria, 12-13 Apr 2007, 93–97.

[5] Malkin Z. On dependence of EOP precision and accuracy on VLBI network. In: Proc. 18th EVGA

Working Meeting, Vienna, Austria, 12-13 Apr 2007, 75–78.

[6] Sokolova, J. Effect of the reference radio source selection on VLBI CRF realization. Presented at Journ ́ees

2007, Paris, September 17–19, 2007.

234 IVS 2007 Annual Report
SHAO, Chinese Academy of Sciences Shanghai Astronomical Observatory Analysis Center

SHAO Analysis Center 2007 Annual Report

Jinling Li

Abstract

Our research activities in 2007 focused on the atmosphere delay calibration of VLBA phasereferencing observations, the selection of stable sources for the next realization of the extragalactic

celestial reference frame, and the processing of the satellite VLBI tracking data. These activities will

be continued next year; in particular, we will prepare the software for the Chinese lunar exploration

and Martian exploration. The local survey at Sheshan section of Shanghai Astronomical Observatory

will be continued too.

1. General Information

We use CALC/SOLVE for our routine VLBI data analysis. We are developing softwares coded

in FORTRAN to deal with the tracking data of satellite by VLBI, ranging, and Doppler. The

members involved in the IVS analysis activities are Jinling Li, Guangli Wang, Bo Zhang, Shubo

Qiao, Li Guo, Feng Tian, and Zhihan Qian.

2. Activities in 2007

We participated in some IERS/IVS campaigns aimed at comparisons of reference frames and/or

Earth Rotation Parameters (EOP). We were able to do the VLBI solutions on a regular base. Our

research activities in 2007 also included the atmosphere delay calibration of the VLBA phasereferencing observations, the selection of stable sources, the processing of the satellite tracking

data, and a local survey at Sheshan section of the Shanghai Astronomical Observatory (SHAO).

2.1. The Atmosphere Delay Calibration of the VLBA Phase-referencing Data

Comparisons between atmospheric delay derived from GPS and VLBI observations at colocation sites show that the standard deviation of the difference is about several millimeters after

a systematic bias is removed. This motivated us to calibrate the VLBA phase-referencing data

using tropospheric estimates from GPS observations.

At present only six VLBA sites are co-located with GPS receivers. Table 1 illustrates the

peak-to-noise ratio (PNR) of source images, where the second and the third column list the PNR

only using geodetic VLBI data and combined GPS and VLBI data, respectively. (In the combined

data column, column 3, if GPS data is available at a station, it is used by itself; if no GPS data

is available, VLBI data is used.) Differences between the PNRs are very small. We therefore

suggest to install GPS receivers at all VLBA sites and to correct for tropospheric effects in VLBA

phase-referencing by using only GPS data or a combination of VLBI and GPS data. The precision

of this correction will be at the millimeter level, while the geodetic VLBI observations could be

omitted or compressed in order to save the observation time of targets.

IVS 2007 Annual Report 235
Shanghai Astronomical Observatory Analysis Center SHAO, Chinese Academy of Sciences

Table 1. Comparison of PNR of source images.

Source PNR (VLBI) PNR (GPS/VLBI)

G350(Maser) 100.1 103.7

1855(QSO) 15.1 16.4

1907(QSO) 15.6 14.1

185X(QSO) 6.7 6.8

2.2. The Selection of Stable Sources

Based on the Calc/Solve system and aiming at the selection of stable sources, we have obtained a

series of global solutions for astrometric/geodetic VLBI observations from 1984 to 2006 by changing

the settings of the control parameters.

Firstly, a selected working list of sources is sorted by declination and then it is divided into

six groups. Mathematically, the i

th source belongs to group j where j = mod(i/6), and if j = 0

then set j = 6. By doing so we obtain similar sky coverage for the six groups. Secondly, take each

of the six groups in turn as arc parameters and all the others as global parameters to obtain the

global solutions of VLBI data. We allow only one sixth of the sources as arc parameters in order

to maintain a uniform reference system. Thirdly, in each of the solutions the frame orientation is

constrained to the ICRF, while different solutions may still have their own orientations that are

slightly different from the others. We perform small angle rotations of the solutions in order to

let the reference systems of all the arc parameters be further unified. Finally, after comparison

and statistical analysis of the solutions we proposed a list of 173 candidate stable sources. We also

compared the list with those recommended by other authors.

2.3. Data Analysis in the Chang’E-1 Project

As designed in the Chinese lunar exploration project Chang’E-1 (CE-1), the tracking data of

satellite consist of range and Doppler measurements from the Chinese United S-Band network as

well as delay and delay rate data from the Chinese VLBI network. We are tasked with processing

the tracking observations of the CE-1 satellite in real-time and we have independently developed

the data reduction software, which provides the instantaneous state vectors (ISVs) including the

three-dimensional position and velocity. The software reads in tracking observations with clock,

instrument, and propagation corrections in real time, automatically identifies the central gravitational body within the Earth-Moon system, and takes into consideration the perturbations of the

non-spherical figure, N-body gravitation, light pressure, atmospheric drag, tidal effects and so on.

The satellite ISVs are sequentially reduced with a 5s sampling interval.

From the ISVs it is easy to get the corresponding orbit elements and to predict the satellite

ephemeris by orbit integration. The ISVs at a specified epoch could be reduced whenever the

independent observations related to the wave-front of signal at this epoch are sufficient, that is,

enough delay and range observations for the three-dimensional position and enough delay rate

and Doppler for the velocity. This reduction is geometrically performed rather than applying

dynamical constraints on the observations belonging to different wave-fronts at different epochs,

and so the length of the tracking arc is not a crucial prerequisite. It could be used to monitor the

quality of tracking data and to identify the evolution of satellite orbit, which satisfies the needs

236 IVS 2007 Annual Report
SHAO, Chinese Academy of Sciences Shanghai Astronomical Observatory Analysis Center

of efficiency and speediness in the view of the implementation of projects. Comparatively, precise

orbit determination requires a sufficiently long tracking arc and is mainly applied in scientific

studies with high precision requirements as in the post-analysis stage rather than in real time.

On November 5 of 2007, CE-1 satellite successfully entered a lunar orbit. During that period

the real-time reduced ISVs from our software very well followed the evolution of the satellite orbit

with a time lag of about five minutes, including the delays for the data transfer from the antenna

to the correlation center, the correlation, the extraction of the delay and rate, among other things.

The next step is to do the synthesis reduction of VLBI observations of satellite and quasars,

especially the differential VLBI observations.

3. Plans for 2008

In the past year, the available time of the 25m antenna at Sheshan was almost completely

used for the CE-1 project, which blocked the progress of the local survey to connect the reference

markers of the SLR, VLBI, and GPS. Now we have local survey network of concrete pillars, a

lease contract for survey instrumentation, auxiliary survey equipment such as the target on the

antenna and the connections of the pillar to the instrument. The first session of the survey should

be completed in 2008.

Other research activities will be continued in 2008, especially, we will get ready in knowledge

and software for the Chinese lunar exploration and Martian exploration. We will make softwares to

automatically do the analysis of the intensive EOP observations, we will also do some comparisons

and combinations of individual EOP time series.

IVS 2007 Annual Report 237
USNO VLBI Analysis Center United States Naval Observatory

U.S. Naval Observatory VLBI Analysis Center

David A. Boboltz, Alan L. Fey, Jennifer L. Bartlett, Zachary Dugan, Kerry A. Kingham,

David M. Hall

Abstract

This report summarizes the activities of the VLBI Analysis Center at the United States Naval

Observatory for calendar year 2007. Over the course of the year, Analysis Center personnel analyzed

biweekly 24-hour experiments with designations IVS-R1 and IVS-R4 for use in-house and continued

timely submission of IVS-R4 databases for distribution to the IVS. During the 2007 calendar year, the

USNO Analysis Center produced three periodic global Terrestrial Reference Frame (TRF) solutions

with designations usn2007a, usn2007b, and usn2007c. Earth orientation parameters (EOP) based on

these solutions, updated by the latest 24-hour (IVS-R1 and IVS-R4) experiments, were submitted to

the IVS.

Other activities in the 2007 calendar year included the generation of a new Sinex solution, usn2007b,

and the continued submission of Sinex files based on new 24-hour experiments to the IVS. In support

of the Celestial Reference Frame (CRF), Analysis Center personnel continued a program designed to

increase the sky density of ICRF sources, especially in the southern hemisphere. Activities included

scheduling, analyzing and submitting databases for IVS-CRF experiments and the production of global

CRF solutions designated crf2007a, crf2007b, and crf2007c. In addition, Analysis Center personnel

performed research into the next generation ICRF-2 and a future high-frequency reference frame based

on the VLBA K/Q-band experiments. Activities planned for the 2008 calendar year include the

continued production of EOP/TRF/CRF global solutions and continued research into future reference

frames.

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 24-hour experiments, the production of periodic global Terrestrial Reference

Frame (TRF) and Celestial Reference Frame (CRF) solutions, and the submission to the IVS of

intensive (EOP-I) and session-based (EOP-S) Earth orientation parameters based on USNO global

TRF 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, USNO personnel engage in research aimed at developing

the next generation ICRF. Information on USNO VLBI analysis activities may be obtained at:

http://rorf.usno.navy.mil/vlbi/.

2. Current Analysis Center Activities

2.1. Experiment Analysis and Database Submission

During the 2007 calendar year, personnel at the USNO VLBI Analysis Center continued processing of 24-hour (IVS-R1 and IVS-R4) experiments for use in internal USNO global TRF and

CRF solutions. USNO is also responsible for the timely analysis of the IVS-R4, and the resulting

databases are submitted within 24 hours of correlation for dissemination by the IVS. In addition,

Analysis Center personnel continue to be responsible for the analysis and database submission

for the periodic IVS-CRF experiments. The primary goal of these experiments is the densifica238 IVS 2007 Annual Report
United States Naval Observatory USNO VLBI Analysis Center

tion of ICRF sources in the southern hemisphere. In 2007, USNO scheduled and analyzed 15 CRF

experiments including IVS-CRF43 through IVS-CRF48, CRF-S11, and IVS-CRDS34 through IVSCRDS41. The analyzed databases were submitted to the IVS. In the 2007 calendar year, Analysis

Center personnel also continued analyzing IVS intensive experiments for use in a USNO EOP-I

time series.

2.2. Global TRF Solutions, EOP and Sinex Submission

USNO VLBI Analysis Center personnel continued to produce periodic global EOP/TRF solutions (usn2007a, usn2007b and usn2007c) over the course of the 2007 calendar year. All USNO

global EOP/TRF solutions including the most recent solution may be found at:

http://rorf.usno.navy.mil/solutions/.

An example of the information available on the Web site is shown in Figure 1. It shows the

distribution of the RMS delays and rates for the 3666 24-hour experiments in the latest USNO

solution, usn2007c. Session-based Earth orientation parameters derived from our solutions are

routinely compared to those derived from GSFC periodic TRF solutions and to the IERS-C05

time series prior to submission to the IVS.

Analysis Center personnel continued to produce an EOP-S series based on the global TRF

solutions and continuously updated by new data from the IVS-R1/R4 experiments. This updated

0 10 20 30 40 50 60 70 80 90 100 110

 0.0

100.0

200.0

300.0

0 100 200 300 400 500 600 700

 0.0

100.0

200.0

300.0

400.0

500.0

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Figure 1. Distribution of RMS delay and rate for the 3666 24-hour sessions in the latest USNO global

TRF/EOP solution usn2007c.

IVS 2007 Annual Report 239
USNO VLBI Analysis Center United States Naval Observatory

EOP-S 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 produced an updated Sinex

series usn2007b and continued to submit Sinex format files based on the 24-hour VLBI sessions.

In addition to EOP-S and Sinex series, USNO Analysis Center personnel continued to produce

and submit to the IVS an EOP-I series based on the IVS intensive experiments.

2.3. Celestial Reference Frame

During the 2007 calendar year, Analysis Center personnel continued work on the production

of global CRF solutions for dissemination by the IVS including crf2007a, crf2007b, and crf2007c.

These solutions are routinely compared to the current ICRF and are available through the previously mentioned Web site: http://rorf.usno.navy.mil/solutions/.

During 2007, Analysis Center personnel performed a variety of CRF related research activities

with the purpose of improving the present ICRF and preparing for future VLBI-based reference

frames. These activities included: the continued densification of the ICRF in the southern hemisphere through IVS-CRF and ATNF/USNO observations, investigations into the costs and benefits

of adding the sources from the VLBA Calibrator Survey (VCS) to the CRF, time series analysis

of source position variations for the purpose of source classification for ICRF-2, and production

of a CRF based upon the 10 VLBA K-band experiments recorded as part of the K/Q-band highfrequency reference frame program. As an example, Figure 2 shows the sky distribution of the

266 sources with three or more delay observations at K-band (24 GHz). Although there have

been only 10 K/Q-band experiments recorded from 2002 to present, the number of observations is

82,354, and the weighted RMS of the differences between the K-band CRF and the ICRF source

positions is only a factor of ∼2.8 times worse than our latest X/S-band CRF with over 5 million

observations.

Figure 2. The distribution of the 266 sources with three or more observations at K-band (24-GHz) plotted

on an Aitoff equal area projection of the celestial sphere. Observations were taken with the VLBA under

the K/Q-band high-frequency reference frame program.

240 IVS 2007 Annual Report
United States Naval Observatory USNO VLBI Analysis Center

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

David Boboltz Periodic global TRF solutions and comparisons, Sinex generation

and submission, Web page administration, VLBI data analysis.

Alan Fey Periodic global CRF solutions and comparisons, CRF densification

research, Web page administration, VLBI data analysis.

Jennifer Bartlett VLBI data analysis, EOP and database submission.

Zachary Dugan VLBI data analysis, EOP and database submission.

Kerry Kingham Correlator interface, VLBI data analysis.

David Hall Correlator Interface, VLBI data analysis.

4. Future Activities

For the upcoming year January 2008–December 2008, USNO VLBI Analysis Center personnel

plan to accomplish the following activities:

• Continue the processing of biweekly IVS-R1/R4 experiments for use in internal TRF and

CRF global solutions and continue submission of IVS-R4 databases for dissemination

by the IVS.

• Continue the production of periodic global TRF 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-hour experiments, and begin

production of a Sinex series based upon the intensive experiments.

• Continue the analysis of intensive experiments and submission of EOP-I estimates to

the IVS.

• Continue the scheduling, analysis and database submission for all IVS-CRF experiments.

• Continue the production of periodic global CRF solutions.

• Continue research into source characterization and the development of the second realization of the ICRF (ICRF-2).

• Continue research into the development of high-frequency reference frames based upon

VLBA K- and Q-band sessions.

IVS 2007 Annual Report 241
USNO Analysis Center for Source Structure U. S. Naval Observatory

USNO Analysis Center for Source Structure Report

Alan L. Fey, David A. Boboltz, Roopesh Ojha, Ralph A. Gaume, Kerry A. Kingham

Abstract

This report summarizes the activities of the United States Naval Observatory Analysis Center

for Source Structure for calendar year 2007. VLBA RDV experiments RDV61, RDV63, and RDV65

were calibrated and imaged. VLBA high frequency experiment BL122D was calibrated and imaged.

Images from these four experiments, together with images from RDV28, were added to the USNO

Radio Reference Frame Image Database. A Southern Hemisphere imaging and astrometry program for

maintenance of the ICRF continued. Activities planned for the year 2008 include continued imaging

of ICRF sources at standard and higher frequencies and continued analysis of source structure and its

variation.

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 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 4980 Very Long Baseline Array (VLBA) images (a 20% increase over the previous year) of

636 sources (a 23% increase over the previous year) at radio frequencies of 2.3 GHz and 8.4 GHz.

Additionally, the RRFID contains 1339 images (a 16% increase over the previous year) of 270

sources (a 1% increase over the previous year) at frequencies of 24 GHz and 43 GHz. The RRFID

can be accessed from the Analysis Center Web page or directly at

http://www.usno.navy.mil/rrfid.shtml

The RRFID also contains 74 Australian Long Baseline Array (LBA) images of 69 southern

hemisphere ICRF sources at a radio frequency of 8.4 GHz.

Shown in Figure 1 is the distribution throughout the sky of the sources which have been imaged

at 2.3 GHz and 8.4 GHz.

2. Current Activities

2.1. VLBA Imaging

VLBA experiment RDV65 (2007AUG01) was calibrated and imaged, adding 203 (102 Sband; 101 X-band) images to the RRFID, including images of 48 sources (0048-427, 0054+161,

0102+511, 0103+127, 0111+131, 0137+012, 0137+467, 0208-512, 0209+168, 0325+395, 0410+110,

242 IVS 2007 Annual Report
U. S. Naval Observatory USNO Analysis Center for Source Structure

Figure 1. Distribution of the sources which have been imaged at 2.3 GHz and 8.4 GHz shown on an Aitoff

equal area projection of the celestial sphere. The size of the open circles indicates roughly the number of

times each source has been imaged as indicated by the key.

0411+054, 0423+237, 0537-286, 0645+209, 0723+219, 0906-048, 0927+469, 1003+351, 1010+495,

1046-026, 1055-242, 1100+122, 1107+485, 1117-248, 1143-332, 1200+468, 1241+166, 1246+489,

1412+461, 1421+122, 1541+050, 1623-243, 1627+476, 1639-062, 1645+174, 1645+271, 1648+084,

1745+670, 1746+470, 1820-274, 1822+033, 1908+484, 2013+508, 2018+282, 2135-184, 2304+377

and 2319+317) not previously imaged.

VLBA experiment RDV63 (2007JUN26) was calibrated and imaged, adding 210 (105 Sband; 105 X-band) images to the RRFID, including images of 49 sources (0025+197, 0134+311,

0211+171, 0239+175, 0307+380, 0312+100, 0415+398, 0442+389, 0548+378, 0641+392, 0729+259,

0743+277, 0747+185, 0828-222, 0951+268, 0958+346, 1013+127, 1040+244, 1054+004, 1059+282,

1125+366, 1145+268, 1212+171, 1218+339, 1306+360, 1348+308, 1424+366, 1441+252, 1520+319,

1608+243, 1639+230, 1651+391, 1722+330, 1725+123, 1736+324, 1754+155, 1846+322, 1909+161,

2000+148, 2013+163, 2029+024, 2155+312, 2201+044, 2205+166, 2205+743, 2214+350, 2216+178,

2318-195, and 2358+189) not previously imaged.

VLBA experiment RDV61 (2007JAN24) was calibrated and imaged, adding 217 (109 S-band;

108 X-band) images to the RRFID, including images of 17 sources (0035-024, 0459+252, 0521-365,

0629+160, 0812+020, 1056+212, 1104-445, 1119+183, 1142+052, 1200+045, 1216+061, 1337-033,

1508-055, 1721+343, 1933-400, 2329-384 and OL224) not previously imaged.

VLBA experiment RDV28 (2001MAY09) was calibrated and imaged, adding 186 (93 S-band;

93 X-band) images to the RRFID, including images of 4 sources (0528-250, 0826-373, 1239+376

and NGC6454) not previously imaged. These results were contributed by Glenn Piner and Corey

Nichols of Whittier College who calibrated, edited, and imaged the data.

Two 24-hour epochs of full polarization VLBA observations of AGN whose scintillation status

IVS 2007 Annual Report 243
USNO Analysis Center for Source Structure U. S. Naval Observatory

(i.e. whether they exhibit scintillation or not) is known, were calibrated, imaged and model fit.

This is part of an ongoing program to study the morphology of scintillating and non-scintillating

extragalactic sources and to explore the possibility of using the presence of scintillation to identify

good new candidate reference frame sources.

Collaborations continue with Glenn Piner at Whittier College and Patrick Charlot of Bordeaux

University to calibrate and image several of the VLBA RDV experiments.

2.2. VLBA High Frequency Imaging

VLBA observations to extend the ICRF to 24 and 43 GHz continued in 2007. These observations are part of a joint program between the National Aeronautics and Space Administration, the

USNO, the National Radio Astronomy Observatory (NRAO) and Bordeaux Observatory. During

the calender year 2007 one VLBA high frequency experiment, BL122D (2007MAR30), was calibrated and imaged adding 185 (K-band only) images to the RRFID including images of 4 sources

not previously imaged.

2.3. ICRF Maintenance in the Southern Hemisphere

The USNO and the Australia Telescope National Facility (ATNF) continue a collaborative

program of VLBI research on Southern Hemisphere source imaging and astrometry using USNO,

ATNF and ATNF-accessible facilities. These observations are aimed specifically toward improvement of the ICRF in the Southern Hemisphere. One celestial reference frame experiment, CRF-S11,

was scheduled with antennas at Hobart, Australia, Hartebeesthoek, South Africa and the 70-meter

Deep Space Network antenna at Tidbinbilla, Australia.

A program to monitor the structure of quasars south of declination −30◦that are either known

to be gamma-ray loud or are expected to be gamma-ray loud was initiated. The program, called

TANAMI (Tracking Active galactic Nuclei with Australia Milliarcsecond Interferometry), will observe a sample of about 44 quasars at 8 GHz and 24 GHz bands, with half of the sample observed

every two months. The first epoch of observations was scheduled and observed.

3. Staff

The staff of the Analysis Center is drawn from individuals who work at the USNO. The staff

are: Alan L. Fey, David A. Boboltz, Roopesh Ojha, Ralph A. Gaume and Kerry A. Kingham.

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 2008 are planned:

• Continue imaging and analysis of VLBA 2.3/8.4/24/43 GHz experiments

• Make additional astrometric and imaging observations in the Southern Hemisphere in collaboration with ATNF partners

244 IVS 2007 Annual Report
Technology Development Centers

Geodetic Survey Division, Natural Resources Canada Canadian TD Center

Canadian VLBI Technology Development Center

Bill Petrachenko

Abstract

The Canadian VLBI Technology Development Center (TDC) is actively involved in theoretical

studies to define recommendations for the VLBI2010 system. In addition, two development programs

at the Dominion Radio Astrophysical Observatory (DRAO) are of potential interest to VLBI2010.

Composite antennas that are light, stiff and cost-effective are being developed for the SKA, and a

state-of-the-art correlator is being developed for the EVLA.

1. Introduction

The Canadian TDC is a collaborative effort of the National partners interested in the advancement of VLBI technology, namely the Geodetic Survey Division of Natural Resources Canada

(GSD/NRCan) and the Dominion Radio Astrophysical Observatory (DRAO) of the Herzberg Institute for Astrophysics of the National Research Council of Canada, (DRAO/HIA/NRC).

A number of the activities of the Canadian TDC were discontinued this year due to the cessation

of VLBI operations in Canada. These include the development and maintenance of the S2 VLBI

system and the Canadian Transportable VLBI antenna (CTVA).

2. VLBI2010 Committee

Activity within the Canadian TDC is now focussed primarily on supporting recommendations

for IVS’s VLBI2010. This is being done through Bill Petrachenko’s participation as chairman of the

V2C. In addition to his leadership role, he has taken an active interest in the feasibility of generating

source structure corrections, in particular, the alignment of images at different frequency bands.

Simulations are ongoing. He also made significant contributions to defining recommendations

for VLBI2010 antenna slew parameters. In collaboration with Toni Searle of NRCan, schedules

were generated to test the dependence of position accuracy on source switching interval. These

schedules were then processed through the Monte Carlo Simulators at TU Wien by Joerg Wresnik

and Andrea Pany and at NASA GSFC by Dan MacMillan. Using the results, it was possible to

develop relations between performance and slew parameters to provide a theoretical backing for

the VLBI2010 slew parameter recommendation.

3. DRAO Activities

DRAO has a long history of participation in VLBI beginning with the first ever successful fringes

in 1967. Expertise exists in a number of relevant disciplines from innovative antenna/feed/receiver

design to the design and implementation of large complex digital systems.

Of particular interest to VLBI2010 are the composite antennas being designed for the Square

Kilometer Array (SKA) project. These are 12 m antennas based on composite materials that are

light, stiff and cost effective. Under the leadership of Dean Chalmers and Gordon Lacy, a first

prototype antenna (10 m) was produced in the summer of 2007. Both holography and a laser

scanning system verified that the antenna surface is good to at least 15 GHz. A second prototype

IVS 2007 Annual Report 247
Canadian TD Center Geodetic Survey Division, Natural Resources Canada

is expected in spring of 2008. As a result of process development, a significant improvement in

surface accuracy is expected.

In addition to the SKA antenna development effort, DRAO, under the leadership of Brent

Carlson and Dave Fort, is producing the correlator for the EVLA project. It is one of the most

ambitious radio interferometry correlators ever conceived, handling, in real time, 32 stations at a

maximum data rate of 96 Gbps per antenna. Although primarily intended for connected element

interferometry, it was also designed to be VLBI capable. An adaptation of the EVLA design

capable of handling VLBI2010 requirements has been investigated.

Figure 1. Ten meter prototype composite antenna at DRAO being prepared for holographic testing.

248 IVS 2007 Annual Report
Forsvarets forskningsinstitutt (FFI) (Norwegian Defence Research Establishment) FFI TD Center

FFI Technology Development Center - Software Development

Per Helge Andersen

Abstract

FFI’s contribution to the IVS as a Technology Development Center focuses primarily on the development and validation of the GEOSAT software for a combined analysis at the observation level of data

from VLBI, GPS, and SLR. This report shortly summarizes the latest improvements of the GEOSAT

software. FFI is currently Analysis Center for IVS and ILRS, Technology Development Center for IVS,

and Combination Research Center for IERS.

1. The GEOSAT Software

FFI’s contribution to the IVS as a Technology Development Center focuses primarily on the

development and validation of the GEOSAT software for a combined analysis at the observation

level of data from VLBI, GPS, and SLR. The advantages of the combination of independent and

complementary space geodetic data at the observation level are discussed in Andersen ([1]). After

five years of development and extensive validation we are proud to announce that a major revision

and extension of the GEOSAT software has been completed. The most important changes implemented have been described in recent IVS Annual Reports. Much more flexibility and automation

have been added. Furthermore, the latest and “best” models (mostly following the IERS Standard) and “calibration tables” and “instrumental/geophysical events tables” have been included.

Analysis of tracking data to S/C’s in deep space has been added. The software automatically

detects the central body if any (the Earth or a body in the solar system) and accordingly performs

the analysis either in a local geocentric frame of reference (if the Earth is the central body) or in

a solar system barycenter frame of reference. It is for example in principle possible to calculate

the trajectory of the S/C and the orbit and gravity field of the central body. For any technique,

the delay due to the troposphere is determined with 3D raytracing using the European Center for

Medium-range Weather Forcast Numerical Weather Model. No mapping functions are used and

the corrections are determined directly from interpolation in the raytracing files. The tropospheric

correction for SLR is rescaled using actual surface met data. For microwave data (GNSS and

VLBI) this is of no importance since empirical zenith delay parameters must be estimated.

2. Staff

Dr. Per Helge Andersen - Research Professor of Forsvarets forskningsinstitutt (FFI) and Institute of Theoretical Astrophysics, University of Oslo.

References

[1] Andersen, P. H. Multi-level arc combination with stochastic parameters. Journal of Geodesy (2000) 74:

531-551.

IVS 2007 Annual Report 249
GSFC Technology Development Center NASA Goddard Space Flight Center

GSFC Technology Development Center Report

Ed Himwich, John Gipson

Abstract

This report summarizes the activities of the GSFC Technology Development Center (TDC) for 2007

and forecasts planned activities for 2008. The GSFC TDC develops station software including the Field

System, scheduling software (SKED), hardware including tools for station timing and meteorology,

scheduling algorithms and operational procedures, and 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

and Ed Himwich, both employed by NVI, Inc. The remainder of this report covers the status of

the main areas of development that are currently being pursued.

2. Field System

The GSFC TDC is responsible for development, maintenance, and documentation of the Field

System (FS) software package. The FS provides equipment control at VLBI stations. It interprets

the .snp schedule and .prc procedure file (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 all the IVS network

stations (over 30) and also at many stations that do VLBI only for astronomical observations. The

only major observatories not using it are the VLBA and VERA.

During this period some of the new features that were released in FS version 9.10 were:

• Support was added for Mark 5B recorders and sampler modules. This included developing

documentation for operations with these systems.

• The FS Linux 6 distribution (based on Debian ‘sarge’) was developed and deployed. This

included changing to use a RAID1 array for the system disks and developing new disk back-up

and rotation procedures for RAID disks.

• The ‘systests’ system test data acquisiton and analysis suite was improved and updated.

This included support for new hardware systems and expanded capabilities for analysis and

plotting.

• Numerous small bug fixes and improvements were added.

In the next year, several other improvements are expected; among these are: (1) Support for

DBBC and DBE racks, (2) a complete update to the documentation and conversion to a more

modern format that will be easier to use; (3) conversion of the FORTRAN source to use the g77

250 IVS 2007 Annual Report
NASA Goddard Space Flight Center GSFC Technology Development Center

compiler; this will enable use of the source level debugger, gdb for development and field debugging;

(4) use of fsvue or Real VNC for remote operation; (5) chekr support for Mark 5A and 5B systems;

(6) use of the Mark IV Decoder for phase-cal extraction in the field; (7) FS Linux 7 (‘etch’)

development; and (8) support for periodic firing of the noise diode during observations.

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 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.

During 2007 many changes were made to SKED and DRUDG. SKED and DRUDG continue to

improve because of changing needs and users’ requests. In both SKED and DRUDG, the maximum

number of stations was increased to 40, the maximum number of sources to 1000, and the maximum

number of scans to 20,000. Many changes were made to SKED to support simulation studies for

VLBI2010. Other changes were made to make scheduling easier. The following summarizes some

of the SKED and DRUDG changes.

3.1. SKED

The following changes were made to SKED.

• SKED used to have an implicit limit of only scheduling for 24 hours. The user can now

schedule for longer than 24 hours.

• Fixed a bug in the calculation of total recorded bits when using Mark5. In most cases,

the number of data channels taken is the same as the number of data channels recorded.

Sometimes this is not true because Mark5 is limited to recording 4, 8, 16, 32 or 64 channels.

If the number of data channels taken is not a power of 2, some channels are duplicated in

recording. For example, in the R4’s prior to 2006, only 14 data channels were taken, although

16 channels were recorded using Mark5. The first two channels were recorded twice. Another

example occurs where some stations do not have the full complement of BBCs. Sked used to

calculate the total disk requirement using the amount of data taken. It now uses the amount

of data recorded.

• Changes were made to the downtime command to make it more flexible.

• A bug in the time window command was fixed. The command major last x is supposed to

set the time window to x hours. Here the time window is used in calculating sky coverage

and covariance information. We discovered that SKED ignored this parameter and used all

observations regardless of the value of x. This was fixed.

• The fill-in mode was made more flexible. Previously the minimum sub-net size and the length

of idle time before considering were hard-wired. These are now user settable parameters.

IVS 2007 Annual Report 251
GSFC Technology Development Center NASA Goddard Space Flight Center

• The master command was introduced. This has two modes: master check checks the schedule

against the master file to make sure that the stations and the times are correct; master get

reads the stations and the times from the master file and modifies the schedule accordingly.

The location of the master file must be specified in the master line of skedf.ctl, e.g.:

master /usr/local/bin/master08.txt.

• The extended listing command was made more flexible. Previously any time you turned on

one option it would turn off all other options. It now toggles the options, and many options

can be specified on a line.

• A sky coverage function was added. SKED divides the sky into 13 equal sized pixels at each

station. The pixel number for each station, and the total number of distinct pixels covered

over the preceding time window can be displayed by turning on the ‘sky’ extended listing:

xl sky. The time window considered is specified by the major command: maj last 0.5 sets a

time window of 0.5 hours.

3.2. DRUDG

The following changes were made to DRUDG.

• Many changes were made to support changing specifications.

• Two new rack types were introduced: Mark 5 and VLBA5.

• Dymo printer support was added for FS Linux 6 (‘sarge’). The cups driver had a bug which

we had to work around.

• Various minor bugs were fixed.

252 IVS 2007 Annual Report
MIT Haystack Observatory Technology Development Center

Haystack Observatory Technology Development Center

Alan Whitney, Arthur Niell

Abstract

Work at MIT Haystack Observatory is currently focusing on four areas: Mark 5C VLBI data

systems, e-VLBI, digital backends, and VLBI2010 progress. We will describe each of these areas.

1. Mark 5C VLBI Data System

The Mark 5C is being designed as the next generation Mark 5 system, with a capability of

recording sustained data rates up to 4096 Mbps. It will use the same disk modules as the Mark

5A and Mark 5B, thus preserving existing investments in disk modules. The Mark 5C data

interface for both recording and playback will be 10 Gigabit Ethernet, which is rapidly becoming a

widely supported standard. The use of 10GigE interfaces comes with some significant implications,

however. Firstly, data sources must be designed to provide data streams in a format compatible

with the Mark 5C requirements. And secondly, data playback through a 10GigE interface is a good

match for a rising generation of software correlators. In the interests of backwards compatibility,

the Mark 5C will also support a mode which writes disk modules in Mark 5B data format which can

be correlated on existing Mark IV correlators that support Mark 5B. Some other characteristics

of the Mark 5C include:

• The standard Mark 5C Ethernet packet format prescribes that each packet contains data

from only a single frequency channel. Unlike almost all previous VLBI data systems, which

constrain the number of recorded frequency channels to be 2n, the Mark 5C will allow an

arbitrary number of channels to be recorded.

• The Mark 5C will use the same Amazon StreamStor disk interface card as the Mark 5B+,

but it will replace the FPDP I/O daughterboard with a newly designed (by Conduant Corporation) 10GigE interface card. Unlike Mark 5A/B/B+, no separate specialized I/O card

is needed.

• At data rates above about 2 Gbps, it will be necessary to record to two 8-disk modules

simultaneously in so-called ‘non-bank’ mode, which is not normally used by Mark 5A or

Mark 5B/5B+.

• Mark 5C will include a Mark 5B emulation mode to create recorded disks that are in the

Mark 5B data format and can be correlated directly on a Mark IV correlator.

The first prototype Mark 5C systems are expected to be available in mid-2008. Additional

detailed information about the Mark 5C systems is available in the Mark 5 memo series

(http://www.haystack.edu/tech/vlbi/mark5/memo.html), particularly memos 57, 58, 61, and 62.

2. e-VLBI Development

Haystack Observatory continues to develop the e-VLBI technique for VLBI data transfers:

• Implementation of automated e-VLBI data transfer capability at MPI correlator: Haystack

has worked with the Bonn correlator at MPI to implement an e-VLBI data transfer capability

IVS 2007 Annual Report 253
Technology Development Center MIT Haystack Observatory

similar to that at Haystack Observatory. This allows the direct transfer to Bonn of data that

will be correlated there. Data from Onsala, Ny- ̊Alesund and Japan are now transmitted

regularly to Bonn over their 1 Gbps network connection.

• 10GigE connection to Haystack: A 10 Gigabit network connection from Washington, D. C.

to Haystack over the Bossnet network has been inaugurated in cooperation with MIT Lincoln

Laboratory. This link is important for e-VLBI data transfers to Haystack and for the testing

of the new VLBI2010 demonstration broadband system utilizing the Westford and MV-3 (at

NASA/GSFC) antennas.

• Real-time e-VLBI processing of Mark 5B data: Work is nearly complete to support realtime e-VLBI using Mark 5B on the Mark IV correlator. We expect to use this system to

demonstrate 2 Gbps real-time e-VLBI in the near future.

3. Digital Backends

In last year’s Technology Development Center report, Haystack reported on the successful

development of the first generation digital backend system, now called DBE1. The DBE1 system

was developed collaboratively with the University of California at Berkeley using the so-called

iBob board that was developed as a flexible general purpose radioastronomy signal processing

platform using FPGA technology. DBE1 systems have now been successfully used in a number of

geodetic and astronomical VLBI experiments. A second generation system, dubbed DBE2, is now

being developed at Haystack based on a next generation iBob, dubbed iBob2. The iBob2 is being

developed by Berkeley, NRAO, and South Africa as the common platform for digital backend

development to meet the specific needs of both NRAO and Haystack. Haystack will design a

polyphase-filter-bank (PFB) version of the FPGA code to process two 1 GHz-wide IFs into an 8

Gbps Ethernet packet stream compatible with the Mark 5C data system. NRAO, on the other

hand, is planning to emulate several VLBA BBCs on an iBob2 board (dubbed VDBE), which will

also produce a Mark 5C-compatible Ethernet data stream. The hardware for both the Haystack

and the NRAO systems will be identical; only the FPGA code will be different, allowing an iBob2

system to adopt the personality of either DBE2 or VDBE. The cost of a DBE2/VDBE system

is not yet well established, but will likely be considerably less than US$10K. The first prototype

DBE2/VDBE systems are expected to be available for testing in mid-2008.

4. VLBI2010

The major innovation of the VLBI2010 concept is the use of a relatively small antenna (∼12 m)

with a receiver spanning a very wide bandwidth (∼2-15 GHz). Observing will utilize four 0.5-1

GHz-wide bands spread across the 2-15 GHz receiver capability in order to gain a group delay

precision sufficient to resolve the more accurate phase delay. This concept has come to be known

as the broadband delay system.

Haystack Observatory has been working with NASA/GSFC and HTSI, along with consultation

from Bill Petrachenko and others, to develop a demonstration system using the broadband delay

concepts. Several advances in technology are necessary in order to create such a system:

Broadband feed: Only recently have feeds with sufficient bandwidth become available to implement the broadband concept. The feed for our initial tests is a commercial wideband (2-13 GHz)

254 IVS 2007 Annual Report
MIT Haystack Observatory Technology Development Center

unit, chosen because it is readily available and relatively inexpensive. A specially designed feed

for VLBI2010 is expected to become available in a year or two. A complication is that these feeds

receive linear polarization, not the circular polarization that we have traditionally used; in order

to deal with antenna parallax differences, it will be necessary to capture both linear polarizations.

Digital backend: Digital backends are a necessity for the broadband systems for several reasons:

1) absolute uniformity and repeatability, 2) wide-bandwidth capabilities, and 3) low cost. For the

demonstration system, the DBE1 unit designed jointly by Haystack Observatory and the University

of California at Berkeley is being used.

High-data-rate data-acquisition system: Multiple Mark 5B+ systems, capable of recording 2

Gbps each, were used at each antenna in the demonstration systems. Processing was done on the

Mark IV correlator at Haystack Observatory. The Mark 5C development, described above, will be

capable of recording 4 Gbps on each system.

In order to demonstrate that the broadband concept is feasible, we have implemented a broadband demonstration system, using the Westford and MV-3 (at NASA/GSFC) antennas, that

utilizes all of the components of a broadband delay system. The combined sensitivity of these

two antennas is somewhat less than that of two high-efficiency 12 m antennas but sufficient to

demonstrate that the concept is valid.

The broadband demonstration system consists of the above-mentioned commercial feed to cover

the frequency range ∼2 GHz to ∼13 GHz in two linear polarizations, along with two low-noise

amplifiers (LNAs). The feed and the LNAs are both cooled to approximately 20K, and the output

of each LNA is carried over wideband “RF” optical fiber to the control room where the signals are

split into four paths corresponding to the four frequency bands. An Up-Down Converter (UDC)

translates both polarizations of each band to a common 500 MHz-wide intermediate frequency

(IF) that is digitized and filtered by the Digital Backend and recorded on a Mark 5B+ recorder.

To observe in four bands requires four UDCs, four Mark 5B+s and two dual-board DBE1s at each

site.

One entire broadband system was installed on MV-3 during the last week of October. The

Dewar was mounted at the Cassegrain focus in the location of the original X-band feed, as can be

seen in Figure 1. For the first test we observed at X-band in the usual geodetic band. Westford

used the operational NASA X-band receiver and LO but recorded using a DBE1 and Mark 5B+.

Since only one band was being recorded, the data rate was only 2 Gbps.

On 19 November 2007 fringes were found for both linear polarizations from MV-3. Vertical

polarization was carried on optical fiber, horizontal on coax. The SNRs on 3C279 were 127 and

117 for 125 seconds of data, close to our predictions. The system temperatures were measured as

approximately 45K and 35K on fiber and coax, respectively. Some fringe-phase differences between

the polarizations were observed that are not yet understood and are being studied. We have also

begun construction of an identical system for Westford where the Dewar will be mounted at prime

focus. Eight UDCs and four dual-board DBEs will be constructed to observe in four frequency

bands. At that time the next round of testing will evaluate the efficiency of the broadband system

mounted on the Westford antenna.

5. Acknowledgements

The broadband demonstration system is funded by NASA’s Earth Surface and Interior Focus

Area through the efforts of John LaBrecque, Chopo Ma, and Herb Frey.

IVS 2007 Annual Report 255
Technology Development Center MIT Haystack Observatory

Figure 1. Jay Redmond and Bruce Whittier installing the Dewar on the 5 m MV-3 antenna.

Important contributions were made by all participants: Arthur Niell and the BBDev Team

(in reverse alphabetical order) Bruce Whittier, Mike Titus, Jason SooHoo, Dan Smythe, Alan

Rogers, Jay Redmond, Mike Poirier, Chuck Kodak, Alan Hinton, Ed Himwich, Skip Gordon,

Mark Evangelista, Irv Diegel, Brian Corey, and Tom Clark.

In addition, the system could not have been put together without the work of Sandy Weinreb

and Hamdi Mani of Caltech, whose design of the Dewar, feed, and LNAs has been copied directly.

Beyond that they have generously provided advice as we constructed the front end for MV-3.

We also want to thank Dan MacMillan, Peter Bolis, Don Sousa, and Dave Fields for their help;

Photonics Systems, Inc. and Linear Photonics, Inc. for loaning us the fiber optic link; and Shep

Doeleman of Haystack for his significant contributions to the successful implementation of the

DBE technology.

256 IVS 2007 Annual Report
Kashima Space Research Center, NICT Technology Development Center at NICT

Technology Development Center at NICT

Tetsuro Kondo, Yasuhiro Koyama, Ryuichi Ichikawa, Mamoru Sekido

Abstract

National Institute of Information and Communications Technology (NICT) has led the development of VLBI technique and has been keeping high activities in both observations and technical developments. This report gives a review of the Technology Development Center (TDC) at NICT and

summarizes recent activities.

1. TDC at NICT

National Institute of Information and Communications Technology (NICT) has published

the newsletter “IVS NICT-TDC News (former 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 through the Internet at following URL

http://www2.nict.go.jp/w/w114/stsi/ivstdc/news-index.html.

2. Staff Members of NICT TDC

Table 1 lists the staff members at NICT who are involved in the VLBI technology development

center at NICT.

Table 1. Staff Members of NICT TDC as of December, 2007 (alphabetical).

Name Works

HOBIGER, Thomas VLBI analysis

ICHIKAWA, Ryuichi CARAVAN∗system, Delta-VLBI, VLBI analysis

ISHII, Atsutoshi CARAVAN system

KAWAI, Eiji 34m and 11m antenna system

KIMURA, Moritaka e-VLBI, Giga-bit system, K5/VSI, Software correlator

KONDO, Tetsuro e-VLBI, K5/VSSP32, Software correlator

KOYAMA, Yasuhiro e-VLBI, VLBI analysis

KUBOKI, Hiromitsu Antenna system, CARAVAN system (left our group in December

2007)

SEKIDO, Mamoru e-VLBI, Delta-VLBI, VLBI analysis

SHIRATO, Kazuyuki Antenna system, e-VLBI

TAKEFUJI, Kazuhiro e-VLBI (joined our group in December 2007)

TAKIGUCHI, Hiroshi e-VLBI, VLBI analysis

TSUTSUMI, Masanori e-VLBI, K5 system

* CARAVAN: Compact Antenna of Radio Astronomy for VLBI Adapted Network system

IVS 2007 Annual Report 257
Technology Development Center at NICT Kashima Space Research Center, NICT

3. Current Status and Activities

3.1. e-VLBI

We have been developing an “ultra-rapid UT1 measurement” system by using an e-VLBI

technique in collaboration with Geographical Survey Institute (GSI Tsukuba, Japan), Onsala

Space Observatory (Sweden), and Mets ̈ahovi Radio Observatory (Finland). The locations of these

stations and a block diagram of the data flow and data processing are indicated in Figure 1. NICT

and Mets ̈ahovi have developed the PC-based VLBI data acquisition systems K5/VSSP and VSIB, respectively. Additionally Mets ̈ahovi developed “real-time Tsunami”, which is a UDP-based

network data transport software for VLBI. These technologies enabled real-time data transfer

in 256 Mbps observation mode. We started the near-real-time UT1-observation project in April

2007. Observation data were transferred from Nordic stations to Kashima with the ‘Tsunami’

software in real time. Then correlation processing and data analysis was performed with software

correlator developed at NICT and CALC/SOLVE software package developed at GSFC. We made

an automated pipeline data processing system. Consequently, UT1 determinations with a minimum

latency of 30 minutes became available by the end of May 2007. The UT1 data measured by this

project is plotted in Figure 2, where the UT1 data by e-VLBI observation is compared with

prediction and rapid combined solution of Bulletin-A. The plot indicates that the UT1 values

observed on these baselines have the same accuracy level as the rapid combined solution. This

e-VLBI project will be continued with the aim of (a) confirming stable operability of ultra-rapid

UT1 observation with e-VLBI technology, (b) improving the observation precision using higher

data rates, and (c) showing consistency of ultra-rapid UT1 results with standard IVS results.

Figure 1. VLBI stations participating in the Ultra-rapid

UT1 measurements and a block diagram of the data flow

and data processing.

Figure 2. Comparison of UT1-UTC from

EOPc04, prediction of Bulletin-A, and eVLBI observation. A linear trend of UT1-

UTC has been removed in advance. It is

obvious that UT1 measured by e-VLBI observation has higher precision than prediction values.

258 IVS 2007 Annual Report
Kashima Space Research Center, NICT Technology Development Center at NICT

3.2. CARAVAN2400 – Contribution to VLBI2010

We have been developing a 2.4 m antenna VLBI system named CARAVAN2400 for various

R&D purposes, such as to evaluate the performance of a small antenna system as geodetic VLBI

system and to test the design of antenna system in VLBI2010, among other things.

Geodetic VLBI with a Gigabit system. In 2006, first geodetic VLBI observations using

the CARAVAN2400 were successfully conducted with Tsukuba 32 m antenna (baseline length is

about 54 km) at X-band using a conventional multi-channel back end system. Eight video channel

signals, each with an 8 MHz bandwidth in X-band, were sampled using K5/VSSP samplers at

both stations. We carried out an experiment again on February 1, 2007, this time to evaluate

the performance of a gigabit system (K5/VSI with 1ch×512MHz) by comparing a geodetic result

with that observed by multi-channel system (K5/VSSP with 8ch×8MHz) simultaneously. The

purpose is to utilize evaluation results to a planned small antenna system dedicated to the precise

measurement of a reference baseline maintained by GSI for the calibration of surveying equipment.

Both results coincide well with each other as shown in Table 2.

Table 2. Baseline length between CARAVAN2400 and Tsukuba 32m observed by K5/VSSP and K5/VSI

K5/VSSP (8ch×8MHz) K5/VSI (1ch×512MHz)

Length (mm) 53814844.5±1.9 53814844.9±4.5

Implementation of a wide-band feed—realizing the smallest S/X band receiving antenna. A quad-ridge horn antenna (QRHA) (Figure 3) that covers 2-18 GHz has been installed

at a main focus point of CARAVAN2400 as a wide-band feed in November 2007. Wide-band RF

signals received by the QRHA are filtered to S and X bands by a diplexer and fed to a VLBI

backend. A fringe test was carried out on December 5, 2007, and fringes were successfully found

for both S and X bands (Figure 4).

Figure 3. A quad-ridge horn antenna (QRHA). It covers 2-18

GHz.

Figure 4. Fringes on S-band (left) and X-band (right) detected by

CARAVAN2400 equipped with a QRHA.

IVS 2007 Annual Report 259
Technology Development Center at NICT Kashima Space Research Center, NICT

3.3. VLBI Using Cs Gas-cell Frequency Standard

A laser-pumped Cs gas-cell atomic frequency standard (Cs gas-cell standard) developed by

Anritsu Co. Ltd. [1] is more stable than the conventional Cs frequency standard and cheaper than

the hydrogen maser frequency standard. A VLBI experiment was performed between Kashima 34

m and Koganei 11 m on July 19, 2007 in order to evaluate its capability in the geodetic VLBI

experiments. At Kashima, the LD-pumped Cesium gas-cell atomic frequency standard (Cs gas-cell

standard) was used in place of the hydrogen maser standard. Although the Allan variance of the

Cs gas-cell standard is worse by a factor of about ten than that of the hydrogen standard, the

analyzed baseline result was almost identical to previous results.

3.4. K5 Samplers

NICT has developed two types of samplers: 1) ADS series sampler equipped with a VSI-H

interface; 2) VSSP series sampler not equipped with a VSI-H but directly connectable to a host

PC. Samplers developed by NICT are summarized in Table 3. Besides NICT, K5/VSSP32 is now

also used routinely for observing at GSI.

Table 3. Specifications of the K5 samplers.

ADS1000 ADS2000 ADS3000 K5/VSSP K5/VSSP32

Ref. Sig. 10 MHz 10 MHz 10 MHz 10 MHz 10/5 MHz

1 PPS 1 PPS 1 PPS 1 PPS 1 PPS

# of Input Ch. 1 16 1 4 4

A/D bits 1, 2 2 8 1, 2, 4, 8 1, 2, 4, 8

Sampling Freq. 512, 1024 2, 4, 8, 16, 2048 0.04, 0.1, 0.2, 0.04, 0.1, 0.2,

(MHz) 32, 64 0.5, 1, 2, 4, 0.5, 1, 2, 4,

8, 16 8, 16, 32, 64

Output Interface VSI-H VSI-H VSI-H ×2 PCI-bus USB2.0

Function — PCAL detection DBBC etc. — digital LPF

4. Future Plans

We have started, in collaboration with GSI, the development of a 1.6m antenna system equipped

with a wide-band feed for the MARBLE (Multiple Antenna Radio-interferometry for Baseline

Length Evaluation) project that is a project to measure a reference baseline maintained by GSI by

using the VLBI technique for the calibration of surveying equipment. Fringe tests will be carried

out in 2008. Regarding a sampler’s development, we will make improvements of ADS3000 so as to

realize multi-channel DBBC.

References

[1] Ouchi, Y., H. Suga, M. Fujita, T. Suzuki, M. Uchino, K. Takahei, M. Tsuda, and Y. Saburi, A highstability laser-pumped Cs gas-cell frequency standard, Proc. 2000 IEEE/EIA International Frequency

Control Symposium and Exhibition, pp.651–655, 2000.

260 IVS 2007 Annual Report
Onsala Space Observatory (OSO) Onsala Space Observatory (OSO), TDC

The IVS Technology Development Center at the Onsala Space

Observatory

R ̈udiger Haas, Magne Hagstr ̈om, Lars-G ̈oran Gunnarsson, Karl- ̊Ake Johansson,

Miroslav Pantaleev, Gunnar Elgered

Abstract

We briefly describe the technical development during 2007 that is related to geodetic VLBI. The work

focussed mainly on a new S/X receiver, a new time lab, and the radiometers.

1. The New Dual Polarization S/X Receiver for the 20 m Telescope

The new dual polarization S/X-receiver [1] was installed in the summer of 2007 on the 20 m

telescope. In the fall additional filters were installed for right circular polarization, since spurious

phase cal signals were detected during several experiments in the low X-band channels. The left

circular polarization will be equipped in early 2008 with better filters, too. It is not yet possible

to read the temperature and the pressure of the cooling system for the HEMT amplifiers directly

with the Field System. Work is in progress to make this possible during 2008.

2. The New Time Lab at the Observatory

In the spring of 2007 a second maser was installed at the observatory in collaboration with SP

Technical Research Institute of Sweden. The aim of the project is to establish a time lab at Onsala

with two masers, a cesium clock, and equipment for GPS time measurements that contributes

to the generation of UTC at BIPM. Another part of the project is the development of accurate

time synchronization using the high speed optical fiber connection at Onsala. Figure 1 shows time

differences with respect to GPS time as measured with the TAC at the observatory, for the old

maser HM01 (Kvarz CHI75), installed in March 1997, and the new maser HM02 (Kvarz CHI-75A),

installed in April 2007. Figure 2 shows the two masers and the racks with GPS time receivers and

other equipment in the temperature and humidity stabilized time lab.

Figure 1. Time differences of the two masers HM01 and HM02 with respect to the GPS-TAC.

IVS 2007 Annual Report 261
Onsala Space Observatory (OSO), TDC Onsala Space Observatory (OSO)

——————————————————————————-

a) b) HM01 c) HM02 d)

Figure 2. Time lab at Onsala: a) Rack with, for example, GPS TAC, several 5 MHz distributions, pulse

distribution unit, b) HM01: Kvarz CHI-75 installed in March 1997, c) HM02 Kvarz CHI-75A installed in

April 2007, d) Rack with, for example, GPS time receivers, AOG (Auxilliary Output Generator) for UTC

generation, and space for the Cesium clock (to be installed during 2008).

3. The Microwave Radiometers at Onsala

Both microwave radiometers, Astrid [2] and Konrad [3], were in maintenance during 2007. The

unstable power supply and the hot load in the 31.4 GHz channel of Astrid were repaired, and

Astrid has worked again since November. The problems with the azimuth and elevation drives of

Konrad have not been solved yet. We expect that the ongoing repair work will be successful and

that Konrad will be working again in early 2008.

262 IVS 2007 Annual Report
Onsala Space Observatory (OSO) Onsala Space Observatory (OSO), TDC

4. A Superconducting Gravimeter at Onsala

During 2007 we started a project to install a superconducting gravimeter at the observatory.

This project involves the construction of a new gravimeter house that will host the superconducting

gravimeter and additionally a platform for absolute gravimeter measurements. The location of this

new building was chosen based on a stability survey of the bedrock at the observatory with a ground

penetrating radar. Construction work will start in early 2008, and we expect the gravimeter

to be installed in mid-2008. Work is ongoing to develop and install sensor systems to monitor

environmental parameters such as ground water level, sea level, and wind forces.

5. Participation in a VLBI2010 Feed Project

In late 2007 we discussed the possibility of participating in a VLBI2010 feed project in collaboration with the antenna group at Chalmers University of Technology the Norwegian Mapping

Authority, the Goddard Space Flight Center, and other potentially interested groups. The project

will aim at the design and construction of a prototype for a dual linearly polarized feed horn

covering 2-15 GHz that should work in a cooled environment. We hope that this project will be

started in early 2008.

6. Outlook and Future Plans

We will work on an improvement of the new S/X receiver, in particular to suppress spurious

phase cal signals in the right circular polarization but also to improve the left circular polarization.

We will also develop the capability of reading important parameters of the receiver directly with

the FS.

The time lab will be equipped with a Cesium clock during 2008, and in collaboration with SP,

time synchronization via optical fiber will be developed.

We will focus on an upgrade of the azimuth and elevation drives of the Konrad radiometer,

and we expect to have them in place and properly working again in early 2008.

The superconducting gravimeter will be installed during 2008, and we will develop and install

various sensors to monitor environmental parameters.

We plan to be a partner in a possible VLBI2010 feed project, especially given the cryogenic

expertise that is available at our observatory.

References

[1] Haas, R., Hagstr ̈om, M., Nilsson, T., Elgered, G.: The IVS Technology Development Center at the

Onsala Space Observatory. In: D. Behrend and K. Baver (eds.): International VLBI Service for Geodesy

and Astrometry 2006 Annual Report, NASA/TP-2007-214151, 263–265.

[2] Elgered, G., and Jarlemark, P.O.J.: Ground-Based Microwave Radiometry and Long-Term Observations of Atmospheric Water Vapor, Radio Science, 33, 707–717, 1998.

[3] Stoew, B., and Rieck, C.: Dual Channel Water Vapour Radiometer Development. In: W. Schl ̈uter

and H. Hase (Eds.): Proceedings of the 13th Working Meeting on European VLBI for Geodesy and

Astrometry, 261–264, 1999.

IVS 2007 Annual Report 263

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1. Introduction

The following bibliography compiles papers that were published in the field of geodetic and

astrometric VLBI during the year 2007. 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 2007

C. Abbondanza, L. Vittuari, P. Sarti, M. Negusini: “An Analysis of Local Tie Vectors

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W. Alef, A. Bertarini, A. Muskens:  ̈ “The Bonn Mark IV Correlator for Astronomy and

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79, Schriftenreihe der Studienrichtung Vermessung und Geoinformation, Technische Universit ̈at

Wien, ISSN 1811-8380, 21–23, 2007.

W. Alef, D.A. Graham, H. Rottmann, A.L. Roy, A. Bertarini, A.T. Deller, S.J.

Tingay: “Software Correlator at MPIfR: Status Report”. In: Proceedings of the 18th European

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Z. Altamimi, X. Collilieux, C. Boucher: “Preliminary Analysis in View of the ITRF2005”.

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540-49349-5, 685–691, 2007.

P.H. Andersen: “FFI Analysis Center”. In: International VLBI Service for Geodesy and Astrometry 2006 Annual Report, edited by D. Behrend and K. Baver, NASA/TP-2007-214151,

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P.H. Andersen: “FFI Technology Development Center – Software Development”. In: International VLBI Service for Geodesy and Astrometry 2006 Annual Report, edited by D. Behrend

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D. Angermann, H. Drewes, M. Krugel, B. Meisel:  ̈ “Advances in Terrestrial Reference

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T. Artz, S. Bockmann, A. Nothnagel, V. Tesmer:  ̈ “ERP Time Series with Daily and

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C.. Barache: “Paris Observatory (OPAR) Data Center”. In: International VLBI Service for

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A. Bertarini, W. Alef, B.E. Corey, A. Nothnagel, R.C. Walker: “Effect on GeodeticVLBI Measurables due to Polarization Leakage in the Receivers”. In: Proceedings of the 18th

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M. B ́erub ́e, A. Searle: “Algonquin Radio Observatory”. In: International VLBI Service for

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M. B ́erub ́e, A. Searle: “Yellowknife Observatory”. In: International VLBI Service for Geodesy

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S. Di Martino, S. La Delfa, G. Patan ́e, M. Negusini: “Studying the Geodynamics of

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IVS Information

Terms of Reference

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 an official Service of the International Association of Geodesy (IAG).

1.2. Objectives

IVS fulfills its charter through the following objectives. The primary objective of IVS is to

foster VLBI programs as a joint service. This is accomplished through close coordination to

provide high-quality VLBI data and products.

The second objective of IVS is to promote research and development activities in all aspects

of the geodetic and astrometric VLBI technique. This objective also supports the integration of

new components into IVS. The further education and training of VLBI participants is supported

through workshops, reports, electronic network connections, and other means.

The third objective of IVS is to interact with the community of users of VLBI products and to

integrate VLBI into a global Earth observing system. IVS interacts closely with the International

Earth Rotation Service (IERS) which is tasked by the IAU and IUGG with maintaining the

international celestial and terrestrial reference frames and with monitoring Earth rotation.

To meet 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 closely coordinates its activities with the astronomical community because of

the dual use of many VLBI facilities and technologies for both astronomy and astrometry/geodesy.

IVS accepts observing proposals for research and operational programs that conform to the

IVS objectives.

1.3. Data Products

VLBI data products contribute uniquely to these important determinations:

• definition and maintenance of the celestial reference frame

• monitoring universal time (UT1) and length of day (LOD)

• 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 inertial reference frame, such as high-precision navigation and positioning. IVS

provides, through the collaborative efforts of its components, a variety of significant VLBI data

products with differing applications, timeliness, detail, and temporal resolution, such as:

IVS 2007 Annual Report 285
Terms of Reference

• all components of Earth orientation parameters at regular intervals

• terrestrial reference frame

• VLBI data in appropriate formats

• VLBI results in appropriate formats

• local site ties to reference points

• high-accuracy station timing data

• surface meteorology, tropospheric and ionospheric measurements

All VLBI data products are archived in IVS Data Centers and are publicly available.

1.4. Research

The VLBI data products are used for research in many related areas of geodesy, geophysics,

and astrometry, such as:

• UT1 and polar motion excitation (over periods of hours to decades)

• solid Earth interior research (mantle rheology, anelasticity, libration, core modes, nutation/precession)

• 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 vertical (scale) component

• climate studies

To support these activities, there are ongoing research efforts whose purpose is to improve and

extend the VLBI technique in such areas as:

• improvements in data acquisition and correlation

• refined data analysis techniques

• spacecraft tracking (Earth-orbiting and interplanetary)

• combination of VLBI data and results with other techniques

2. Permanent Components

IVS acquires VLBI data, correlates the data, analyzes the data to produce geodetic, astrometric,

and other results, and archives and publicizes data products. IVS accomplishes its goals through

the types of permanent components described in this section. IVS will accept proposals at any

time for a permanent component. Such proposals will be reviewed by the Directing Board. The

seven types of IVS permanent components are:

• Network Stations

• Operation Centers

• Correlators

286 IVS 2007 Annual Report
Terms of Reference

• Analysis Centers

• Data Centers

• Technology Development Centers

• Coordinating Center

IVS acquires VLBI data, correlates the data, analyzes the data to produce geodetic and astrometric results, and archives and publicizes data products. IVS accomplishes its goals through the

operational components described below.

2.1. Network Stations

The IVS observing network consists of high performance VLBI stations.

• Stations can 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 set

up by the Directing Board.

• VLBI data acquisition sessions are conducted by groups of Network Stations that are distributed either globally or over a geographical region.

2.2. Operation Centers

The IVS Operation Centers coordinate the routine operations of one or more networks. Operation Center activities include:

• planning network observing programs,

• establishing operating plans and procedures for the stations in the network,

• supporting the network stations in improving their performance,

• making correlator time available at an IVS Correlator,

• generating the detailed observing schedules for use in data acquisition sessions by IVS Network Stations,

• posting the observing schedule to an IVS Data Center for distribution and to the Coordinating Center for archiving.

IVS Operation Centers follow guidelines from the Coordinating Center for timeliness and schedule

file formats. Operation Centers cooperate with the Coordinating Center in order to define:

• the annual master observing schedule,

• the use of antenna time,

• tape availability and shipping,

• the use of other community resources.

IVS 2007 Annual Report 287
Terms of Reference

• President of IAU Commission 19 – Rotation of the Earth

• President of IAU Commission 8 – Positional Astronomy

• President of IAU Commission 31 – Time

• President of IAU Commission 40 – Radio Astronomy

• President of URSI Commission J – Radio Astronomy

Individuals are accepted as IVS Corresponding Members upon request to the Coordinating Center.

Last modified: 7 October, 2007

294 IVS 2007 Annual Report
Terms of Reference

2.3. Correlators

The IVS Correlators process raw VLBI data and station log files following a data acquisition

session. Their other tasks are to:

• provide immediate feedback to the Network Stations about problems that are apparent in

the data,

• jointly maintain the geodetic/astrometric community’s tape pool,

• make processed data available to the Analysis Centers,

• 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 Analysis Centers and by Associate Analysis Centers.

Analysis Centers are committed to produce series of Earth Orientation Parameters (EOP) or

series of individual EOP components, without interruption and at a specified time lag to meet IVS

requirements. In addition, Analysis Centers produce station coordinates and source positions in

regular intervals.

The 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 Analysis Center

makes from IVS recommendations are properly documented. Analysis Centers provide timely

feedback about station performance. In addition to these regular services, 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.

2.5. Data Centers

The IVS Data Centers are repositories for VLBI observing schedules, station log files, and data

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.

• 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:

288 IVS 2007 Annual Report
Terms of Reference

• 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,

• 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. They may be engaged in hardware and/or software technology development, or evolve new

approaches that will improve the VLBI technique and enhance compatibility with different data

acquisition terminals. They will:

• design new hardware,

• investigate new equipment,

• develop new software for operations, processing or analysis,

• generate new information systems,

• develop, test, and document prototypes of new equipment or software,

• assist with deployment, installation, and training for any new approved technology.

• After dissemination of the new hardware or software, the centers may continue to provide

maintenance and updating functions.

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 all IVS activities.

The primary functions of the Coordinating Center are to:

• coordinate observing programs approved by the Directing Board,

• maintain the master schedule of observing sessions, coordinating the schedule with astronomical observing programs and with IVS networks,

• foster communications among all components of the IVS,

• define the best use of community resources,

• develop standards for IVS components,

• provide training in VLBI techniques,

• organize workshops and meetings, including an annual IVS technical meeting,

• produce and publish reports of activities of IVS components,

IVS 2007 Annual Report 289
Terms of Reference

• maintain the IVS information system and archive all documents, standards, specifications,

manuals, reports, and publications,

• provide liaison with the IERS, IAG, IAU, FAGS, and other organizations,

• provide the Secretariat of the Directing Board.

3. Coordinators

Specific IVS activities for technology, network data quality, and data products 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 Networks 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 operation 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,

The Network Coordinator works closely with the geodetic and astronomical communities who

are using the same network stations for observations. The Coordinator takes a leading role in

ensuring the visibility and representation of the Networks.

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 analysis software documentation,

• 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 analysis products from all Analysis Centers are archived and available for the

scientific community, and

• forms the official products of IVS, as decided by the IVS Directing Board, using a suitable

combination of the analysis results submitted by the Analysis Centers.

290 IVS 2007 Annual Report
Terms of Reference

The Analysis Coordinator works closely with the geodetic and astronomical communities who

are using some of the same analysis methods and software. The Analysis Coordinator plays a

leadership role in the development of methods for distribution of VLBI products so that the

products reach the widest possible base of users in a timely manner. The coordinator promotes the

use of VLBI products to the broader scientific community and interacts with the IVS Coordinating

Center and with the IERS.

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 is

responsible for coordinating the new technology activities of IVS and for stimulating advancement

of the VLBI technique. The Technology Coordinator performs the following functions:

• maintains cognizance of all current VLBI technologies and ongoing development

• coordinates development of new technology among various IVS components

• helps promulgate new technologies to the geodetic/astrometric community

• strives to ensure the highest degree of global compatibility of VLBI data acquisition systems

The Technology Coordinator works closely with the astronomical community because of the

many parallels between the technology development required for both groups.

4. Directing Board

4.1. Roles and Responsibilities

The Directing Board determines policies, adopts standards, and approves 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.

A specific function of the Board is to set scientific goals for the IVS observing program. The

Board will establish procedures for external research programs and will review any proposals thus

received.

The Board may determine appropriate actions to ensure the quality of the IVS products and

that the IVS components maintain the adopted standards.

4.2. Membership

The Directing Board consists of appointed members who serve ex officio, members elected by

the Directing Board, and members elected by the IVS components. The members are:

Appointed members ex officio:

• IAG representative

• IAU representative

• IERS representative

• FAGS representative

IVS 2007 Annual Report 291
Terms of Reference

• Coordinating Center Director

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.

Selected by Directing Board upon review of proposals from IVS Member Organizations:

• Technology, Network, and Analysis Coordinators (3 total)

Elected by Directing Board upon recommendation from the Coordinating Center (see below):

• Members at large (3)

Elected by IVS Components (see below):

• Correlators and Operation Centers representative (1)

• Analysis and Data Centers representative (1)

• Networks representatives (2)

• Technology Development Centers representative (1)

Total number: 16

The five appointed members are considered ex officio and are not subject to institutional restrictions. The FAGS representative is a non-voting member in accordance with FAGS requirements.

The five members of the Directing Board who are elected by IVS Permanent Components must

each be a member of a different IVS Member Organization. All elected members serve staggered

four-year 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 2-year terms once renewable.

A 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 for the remainder of the original term.

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 three months notice before resigning.

4.3. Elections

Election of Board members by 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 possibility of reelection for one additional term. The chair is the official

representative of IVS to external organizations.

292 IVS 2007 Annual Report
Terms of Reference

4.5. Decisions

Most decisions by the Board are made by consensus or by simple majority vote of the members

present. In case of a tie, the chair shall vote but otherwise does not vote. 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 change any of the members

elected by the Directing Board before the normal term expires.

4.6. Meetings

The 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. The reviews should be done every four

years.

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 Correspondents.

5.3. Associate Members

Individuals associated with organizations that support an IVS component may become IVS

Associate Members. Associate Members are generally invited to attend non-executive sessions of

the Directing Board meetings with voice but without vote. 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 on a mailing list maintained by the Coordinating

Center. They do not actively participate in IVS but 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 General Secretary

• President of IAG Commission 1 – Reference Frames

• President of IAG Commission 3 – Geodynamics

• President of IAU Division I – Fundamental Astronomy

IVS 2007 Annual Report 293
Members

IVS Member Organizations

(alphabetized by country)

Organization Country

Geoscience Australia Australia

University of Tasmania Australia

Vienna University of Technology Austria

Centro de R ́adio Astronomia e Aplica ̧c ̃oes Espaciais Brazil

Space Geodynamics Laboratory Canada

Geodetic Survey Division, Natural Resources Canada Canada

Dominion Radio Astrophysical Observatory Canada

Canadian Space Agency Canada

Universidad de Concepci ́on Chile

Universidad del B ́ıo B ́ıo Chile

Instituto Geogr ́afico Militar Chile

Chinese Academy of Sciences China

Observatoire de Paris France

Observatoire de Bordeaux France

Deutsches Geod ̈atisches Forschungsinstitut Germany

Bundesamt f ̈ur Kartographie und Geod ̈asie Germany

Forschungseinrichtung Satellitengeod ̈asie, TU Munich Germany

Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn Germany

Istituto di Radioastronomia INAF Italy

Agenzia Spaziale Italiana Italy

Geographical Survey Institute Japan

National Institute of Information and Communications Technology Japan

National Astronomical Observatory of Japan Japan

National Institute of Polar Research Japan

Norwegian Defence Research Establishment Norway

Norwegian Mapping Authority Norway

Astronomical Institute of St.-Petersburg University Russia

Central (Pulkovo) Astronomical Observatory Russia

Institute of Applied Astronomy Russia

Hartebeesthoek Radio Astronomy Observatory South Africa

Instituto Geogr ́afico Nacional Spain

Chalmers University of Technology Sweden

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

IVS 2007 Annual Report 295
Affiliates

IVS Affiliated Organizations

Organization Country

Australian National University Australia

University of New Brunswick Canada

Max-Planck-Institut f ̈ur Radioastronomie Germany

Satellite Geodetic Observatory Hungary

Korea Astronomy Observatory Korea

Joint Institute for VLBI in Europe (JIVE) Netherlands

Westerbork Observatory Netherlands

National Radio Astronomy Observatory USA

296 IVS 2007 Annual Report
Associate Members

IVS Associate Members

Name Institution Country E-mail

Amagai, Jun National Institute of Information

and Communications Technology

Japan amagai@nict.go.jp

Andersen, Per

Helge

Norwegian Defence Research

Establishment

Norway per-helge.andersen@ffi.no

Andreeva,

Tatiana

Institute of Applied Astronomy Russia ats@urania.rtf32s.nw.ru

Arias, Felicitas Bureau International des Poids

et Mesures

France farias@si.bipm.fr

Artz, Thomas Institute for Geodesy and

Geoinformation of the University

of Bonn

Germany thomas.artz@uni-bonn.de

Barache,

Christophe

Observatoire de Paris France Christophe.Barache@obspm.fr

Baudry, Alain Observatoire de Bordeaux France baudry@obs.u-bordeaux1.fr

Bauernfeind,

Erhard

Fundamentalstation Wettzell Germany bauernfeind@fs.wettzell.de

Baver, Karen NVI, Inc./GSFC USA karen.d.baver@nasa.gov

Beck, Norman Natural Resources Canada Canada beck@nrcan.gc.ca

Behrend, Dirk NVI, Inc./GSFC USA dirk.behrend@nasa.gov

Bellanger,

Antoine

Observatoire de Bordeaux France bellanger@obs.u-bordeaux1.fr

Berdnikov,

Anton

Institute of Applied Astronomy Russia anton ipa@rambler.ru

Bergman, Per Onsala Space Observatory Sweden bergman@oso.chalmers.se

Bernhart,

Simone

Institute for Geodesy and

Geoinformation of the University

of Bonn

Germany simone@mpifr-bonn.mpg.de

Bertarini,

Alessandra

Institute for Geodesy and

Geoinformation of the University

of Bonn

Germany abertari@mpifr-bonn.mpg.de

Bianco,

Giuseppe

Agenzia Spaziale Italiana Italy bianco@asi.it

Bielmaier,

Ewald

Fundamentalstation Wettzell Germany bielmaier@fs.wettzell.de

Boboltz, David U. S. Naval Observatory USA dboboltz@usno.navy.mil

B ̈ockmann,

Sarah

Institute for Geodesy and

Geoinformation of the University

of Bonn

Germany boeckmann@uni-bonn.de

B ̈ohm, Johannes Institute of Geodesy and

Geophysics

Austria johannes.boehm@tuwien.ac.at

Boer, Armin BKG/Project TIGO Chile armin.boer@bkg.bund.de

Bolotin, Sergei Main Astronomical Observatory Ukraine bolotin@mao.kiev.ua

IVS 2007 Annual Report 297
Associate Members

Name Institution Country E-mail

Booth, Roy Hartebeesthoek Radio

Astronomy Observatory

South

Africa

roy@hartrao.ac.za

Bougeard,

Mireille

Observatoire de Paris France mireille.bougeard@obspm.fr

Bourda,

Geraldine

Observatoire de Bordeaux France bourda@obs.u-bordeaux1.fr

Buttaccio, Salvo Istituto di Radioastronomia

INAF

Italy s.buttaccio@ira.inaf.it

Cappallo, Roger MIT Haystack Observatory USA rcappallo@haystack.mit.edu

Carlson, Brent Dominion Radio Astrophysical

Observatory

Canada bcarlson@drao.nrc.ca

Carter, Merri

Sue

U. S. Naval Observatory USA msc@nofs.navy.mil

Charlot, Patrick Observatoire de Bordeaux France charlot@obs.u-bordeaux1.fr

Collioud,

Arnaud

Observatoire de Bordeaux France collioud@obs.u-bordeaux1.fr

Colomer,

Francisco

Instituto Geogr ́afico Nacional Spain f.colomer@oan.es

Colucci,

Giuseppe

Telespazio SpA Italy giuseppe.colucci@telespazio.com

Combrinck,

Ludwig

Hartebeesthoek Radio

Astronomy Observatory

South

Africa

ludwig@bootes.hartrao.ac.za

Conway, John Onsala Space Observatory Sweden john.conway@chalmers.se

Corey, Brian MIT Haystack Observatory USA bcorey@haystack.mit.edu

Dassing, Reiner Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany reiner.dassing@bkg.bund.de

Del Rosso,

Domenico

Telespazio SpA Italy domenico delrosso@telespazio.it

de-Vicente,

Pablo

Instituto Geogr ́afico Nacional Spain p.devicente@oan.es

Dewdney, Peter Dominion Radio Astrophysical

Observatory

Canada ped@drao.nrc.ca

Diakov, Alexey Institute of Applied Astronomy Russia ipazel@mail.svkchr.ru

Dickey, John University of Tasmania Australia John.Dickey@utas.edu.au

Diegel, Irv Honeywell TSI USA irv.diegel@honeywell-tsi.com

Digre, Helge Norwegian Mapping Authority Norway helge.digre@statkart.no

Doi, Koichiro National Institute of Polar

Research

Japan doi@nipr.ac.jp

Dong, Yousuo Urumqi Astronomical

Observatory

China dongys@ms.xjb.ac.cn

Drewes,

Hermann

Deutsches Geod ̈atisches

Forschungsinstitut

Germany drewes@dgfi.badw.de

Dube, Maurice SSAI/GSFC USA maurice.p.dube@nasa.gov

Elgered, Gunnar Onsala Space Observatory Sweden kge@oso.chalmers.se

298 IVS 2007 Annual Report
Associate Members

Name Institution Country E-mail

Engelhardt,

Gerald

Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany gerald.engelhardt@bkg.bund.de

Engen, Bjorn Norwegian Mapping Authority Norway bjorn.engen@statkart.no

Evangelista,

Mark

Honeywell TSI USA mark.evangelista@honeywelltsi.com

Fan, Qingyuan Shanghai Astronomical

Observatory

China qyfan@center.shao.ac.cn

Fedotov, Leonid Institute of Applied Astronomy Russia flv@ipa.nw.ru

Fey, Alan U. S. Naval Observatory USA afey@usno.navy.mil

Finkelstein,

Andrey

Institute of Applied Astronomy Russia amf@quasar.ipa.nw.ru

Fujisaku,

Junichi

Geographical Survey Institute Japan vlbi@gsi.go.jp

Fukuzaki,

Yoshihiro

Geographical Survey Institute Japan fukuzaki@gsi.go.jp

Gambis, Daniel Observatoire de Paris France daniel.gambis@obspm.fr

Gaume, Ralph U. S. Naval Observatory USA rgaume@usno.navy.mil

Gipson, John NVI, Inc./GSFC USA john.m.gipson@nasa.gov

Gomez, Frank Raytheon/GSFC USA frank.g.gomez@nasa.gov

GomezGonzalez,

Jesus

Instituto Geogr ́afico Nacional Spain gomez@oan.es

Gontier,

Anne-Marie

Observatoire de Paris France anne-marie.gontier@obspm.fr

Gordon, David NVI, Inc./GSFC USA david.gordon-1@nasa.gov

Govind, Ramesh Geoscience Australia Australia ramesh.govind@ga.gov.au

Gubanov,

Vadim

Institute of Applied Astronomy Russia gubanov@quasar.ipa.nw.ru

Haas, R ̈udiger Onsala Space Observatory Sweden rudiger.haas@chalmers.se

Hall, David U. S. Naval Observatory USA dhall@usno.navy.mil

Hammargren,

Roger

Onsala Space Observatory Sweden roger.hammargren@chalmers.se

Hanssen, Rune Norwegian Mapping Authority Norway rune.hanssen@statkart.no

Harms, Matt Honeywell TSI USA kokee@pele.kpgo.hawaii.edu

Hase, Hayo BKG/Project TIGO Chile hayo.hase@bkg.bund.de

Heinkelmann,

Robert

Institute of Geodesy and

Geophysics

Austria rob@mars.hg.tuwien.ac.at

Helldner, Leif Onsala Space Observatory Sweden helldner@oso.chalmers.se

Herrera,

Cristian

TIGO/Universidad de

Concepci ́on

Chile cristian.herrera@tigo.cl

Himwich, Ed NVI, Inc./GSFC USA ed.himwich@nasa.gov

Hirabaru,

Masaki

National Institute of Information

and Communications Technology

Japan masaki@nict.go.jp

IVS 2007 Annual Report 299
Associate Members

Name Institution Country E-mail

Hobiger,

Thomas

National Institute of Information

and Communications Technology

Japan hobiger@nict.go.jp

Hong, Xiaoyu Shanghai Astronomical

Observatory

China xhong@center.shao.ac.cn

Honma, Mareki National Astronomical

Observatory of Japan

Japan honmamr@cc.nao.ac.jp

Huang, Xinyong Shanghai Astronomical

Observatory

China xhuang@center.shao.ac.cn

Hugentobler,

Urs

Fundamentalstation Wettzell Germany urs.hugentobler@bv.tu-muenchen.de

Ichikawa,

Ryuichi

National Institute of Information

and Communications Technology

Japan richi@nict.go.jp

Ihde, Johannes Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany johannes.ihde@bkg.bund.de

Ilijin, Gennadiy Institute of Applied Astronomy Russia igen@ipa.rssi.ru

Ipatov,

Alexander

Institute of Applied Astronomy Russia ipatov@ipa.rssi.ru

Ipatova, Irina Institute of Applied Astronomy Russia ipatova@isida.ipa.rssi.ru

Ishii, Atsutoshi National Institute of Information

and Communications Technology

Japan ishii@nict.go.jp

Ivanov, D.V. Institute of Applied Astronomy Russia ltf@ipa.rssi.ru

Iwata, Etsurou Geographical Survey Institute Japan vlbi@gsi.go.jp

Jacobs, Chris Jet Propulsion Laboratory USA chris.jacobs@jpl.nasa.gov

Jara, Cristobal TIGO/Universidad de

Concepci ́on

Chile cristobal.jara@tigo.cl

Jike, Takaaki National Astronomical

Observatory of Japan

Japan jike@miz.nao.ac.jp

Johansson, Jan Onsala Space Observatory Sweden jmj@oso.chalmers.se

Johansson,

Karl- ̊Ake

Onsala Space Observatory Sweden karl-ake.johansson@chalmers.se

Johansson, Lars Onsala Space Observatory Sweden

Johnson, Heidi MIT Haystack Observatory USA hjohnson@haystack.mit.edu

Johnston,

Kenneth

U. S. Naval Observatory USA kjj@astro.usno.navy.mil

Kaufmann,

Pierre

Centro de R ́adio Astronomia e

Aplica ̧c ̃oes Espaciais

Brazil kaufmann@usp.br

Kawaguchi,

Noriyuki

National Astronomical

Observatory of Japan

Japan kawagu.nori@nao.ac.jp

Kawai, Eiji National Institute of Information

and Communications Technology

Japan kawa@nict.go.jp

Kaydanovsky,

Michael

Institute of Applied Astronomy Russia kmn@isida.ipa.rssi.ru

Kharinov,

Mikhail

Institute of Applied Astronomy Russia kharinov@ipa.rssi.ru

Kilger, Richard Fundamentalstation Wettzell Germany kilger@fs.wettzell.de

300 IVS 2007 Annual Report
Associate Members

Name Institution Country E-mail

Kim, Kelly Honeywell TSI USA kokee@pele.kpgo.hawaii.edu

Kimura,

Moritaka

National Institute of Information

and Communications Technology

Japan mkimura@nict.go.jp

Kingham, Kerry U. S. Naval Observatory USA kak@cygx3.usno.navy.mil

Kobayashi,

Hideyuki

National Astronomical

Observatory of Japan

Japan hideyuki.kobayashi@nao.ac.jp

Kokado,

Kensuke

Geographical Survey Institute Japan vlbi@gsi.go.jp

Kondo, Tetsuro National Institute of Information

and Communications Technology

Japan kondo@nict.go.jp

Korkin, Edward Institute of Applied Astronomy Russia korkin@isida.ipa.rssi.ru

Koyama,

Yasuhiro

National Institute of Information

and Communications Technology

Japan koyama@nict.go.jp

Krasinsky,

George

Institute of Applied Astronomy Russia kra@quasar.ipa.nw.ru

Kronschnabl,

Gerhard

Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany gerhard.kronschnabl@bkg.bund.de

Kr ̈ugel,

Manuela

Deutsches Geod ̈atisches

Forschungsinstitut

Germany kruegel@dgfi.badw.de

Kuboki,

Hiromitsu

National Institute of Information

and Communications Technology

Japan kuboki@nict.go.jp

Kudryashova,

Maria

Astronomical Institute of

St.-Petersburg

Russia kudryashova@mercury.astro.spbu.ru

Kurdubov,

Sergey

Institute of Applied Astronomy Russia ksl@quasar.ipa.nw.ru

Labelle, Ruth SSAI/GSFC USA ruth.e.labelle@nasa.gov

Lambert,

Sebastien

Observatoire de Paris France sebastien.lambert@obspm.fr

Lanotte,

Roberto

Telespazio SpA Italy lanotte@asi.it

Lauber, Pierre Fundamentalstation Wettzell Germany lauber@fs.wettzell.de

Lavrov, Alexey Institute of Applied Astronomy Russia lexslavrov@yandex.ru

Li, Bing Shanghai Astronomical

Observatory

China bing@center.shao.ac.cn

Li, Huihua Shanghai Astronomical

Observatory

China hhl@center.shao.ac.cn

Li, Jinling Shanghai Astronomical

Observatory

China jll@center.shao.ac.cn

Liang, Shiguang Shanghai Astronomical

Observatory

China sgliang@center.shao.ac.cn

Lidberg, Martin Onsala Space Observatory Sweden martin.lidberg@chalmers.se

Lindqvist,

Michael

Onsala Space Observatory Sweden michael.lindqvist@chalmers.se

Liu, Xiang Urumqi Astronomical

Observatory

China liux@ms.xjb.ac.cn

IVS 2007 Annual Report 301
Associate Members

Name Institution Country E-mail

Long, Jim Honeywell TSI USA jim.long@honeywell-tsi.com

Lonsdale, Colin MIT Haystack Observatory USA clonsdale@haystack.mit.edu

Lowe, Stephen Jet Propulsion Laboratory USA steve.lowe@jpl.nasa.gov

Lucena, Antonio Centro de R ́adio Astronomia e

Aplica ̧c ̃oes Espaciais

Brazil macilio@roen.inpe.br

Luzum, Brian U. S. Naval Observatory USA bjl@maia.usno.navy.mil

Ma, Chopo NASA Goddard Space Flight

Center

USA chopo.ma-1@nasa.gov

Maccaferri,

Giuseppe

Istituto di Radioastronomia

INAF

Italy g.maccaferri@ira.inaf.it

Machida,

Morito

Geographical Survey Institute Japan machida@gsi.go.jp

MacMillan, Dan NVI, Inc./GSFC USA daniel.s.macmillan@nasa.gov

Malkin, Zinovy Pulkovo Observatory Russia malkin@gao.spb.ru

Manabe, Seiji National Astronomical

Observatory of Japan

Japan manabe@miz.nao.ac.jp

Mantovani,

Franco

Istituto di Radioastronomia

INAF

Italy f.mantovani@ira.inaf.it

Mardyshkin,

Vyacheslav

Institute of Applied Astronomy Russia vvm@isida.ipa.rssi.ru

Marshalov,

Dmitry

Institute of Applied Astronomy Russia dam@ipa.rssi.ru

Matsuzaka,

Shigeru

Geographical Survey Institute Japan shigeru@gsi.go.jp

McCarthy,

Dennis

U. S. Naval Observatory USA dmc@maia.usno.navy.mil

Melnikov,

Alexey

Institute of Applied Astronomy Russia melnikov@quasar.ipa.nw.ru

Mendes

Cerveira, Paulo

Institute of Geodesy and

Geophysics

Austria mendes@mars.hg.tuwien.ac.at

Michailov,

Andrey

Institute of Applied Astronomy Russia agm@isida.ipa.rssi.ru

Miller, Natalia Pulkovo Observatory Russia natmiller@list.ru

Mitchell,

Donald

Honeywell TSI USA kokee@pele.kpgo.hawaii.edu

M ̈uskens, Arno Institute for Geodesy and

Geoinformation of the University

of Bonn

Germany mueskens@mpifr-bonn.mpg.de

Nakajima,

Junichi

National Institute of Information

and Communications Technology

Japan nakaji@nict.go.jp

Nanni, Mauro Istituto di Radioastronomia

INAF

Italy m.nanni@ira.inaf.it

Negusini, Monia Istituto di Radioastronomia

INAF

Italy m.negusini@ira.inaf.it

302 IVS 2007 Annual Report
Associate Members

Name Institution Country E-mail

Nicolson,

George

Hartebeesthoek Radio

Astronomy Observatory

South

Africa

george@bootes.hartrao.ac.za

Niell, Arthur MIT Haystack Observatory USA aniell@haystack.mit.edu

Nikitin, Pavel Crimean Astrophysical

Observatory

Ukraine nikitin@crao.crimea.ua

Nilsson, Bi ̈orn Onsala Space Observatory Sweden biorn.nilsson@chalmers.se

Nilsson, Tobias Onsala Space Observatory Sweden tobias.nilsson@chalmers.se

Noll, Carey NASA Goddard Space Flight

Center

USA carey.noll@nasa.gov

Nothnagel, Axel Geodetic Institute of the

University of Bonn

Germany nothnagel@uni-bonn.de

Nozawa,

Kentarou

Geographical Survey Institute Japan aes@garnet.gsi.go.jp

Ogaja, Clement Geoscience Australia Australia Clement.Ogaja@ga.gov.au

Ojha, Roopesh U. S. Naval Observatory USA rojha@usno.navy.mil

Olofsson, Hans Onsala Space Observatory Sweden hans.olofsson@chalmers.se

O ̃nate, Eric TIGO/Universidad del B ́ıo B ́ıo Chile eric.onate@tigo.cl

Orfei, Sandro Istituto di Radioastronomia

INAF

Italy a.orfei@ira.inaf.it

Pany, Andrea Institute of Geodesy and

Geophysics

Austria apany@mars.hg.tuwien.ac.at

Petrachenko,

William

Natural Resources Canada Canada Bill.Petrachenko@nrc-cnrc.gc.ca

Petrov, Leonid NVI, Inc./GSFC USA Leonid.Petrov@lpetrov.net

Pettersson, Lars Onsala Space Observatory Sweden larsp@oso.chalmers.se

Pl ̈otz, Christian Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany christian.ploetz@bkg.bund.de

Poirier, Michael MIT Haystack Observatory USA mpoirier@haystack.mit.edu

Qian, Zhihan Shanghai Astronomical

Observatory

China qzh@center.shao.ac.cn

Quick, Jonathan Hartebeesthoek Radio

Astronomy Observatory

South

Africa

jon@bootes.hartrao.ac.za

Rahimov, Ismail Institute of Applied Astronomy Russia rahimov@urania.rtf32s.nw.ru

Redmond, Jay Honeywell TSI USA jay.redmond@honeywell-tsi.com

Reid, Brett University of Tasmania Australia brett.reid@utas.edu.au

Rekkedal, Svein Norwegian Mapping Authority Norway svein.rekkedal@statkart.no

Richter, Bernd Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany bernd.richter@bkg.bund.de

Rioja, Maria Instituto Geogr ́afico Nacional Spain mj.rioja@oan.es

Ruszczyk,

Chester

MIT Haystack Observatory USA chester@haystack.mit.edu

Salnikov,

Alexander

Institute of Applied Astronomy Russia salnikov@isida.ipa.rssi.ru

IVS 2007 Annual Report 303
Associate Members

Name Institution Country E-mail

Sarti, Pierguido Istituto di Radioastronomia

INAF

Italy p.sarti@ira.inaf.it

Schatz,

Raimund

Fundamentalstation Wettzell Germany schatz@fs.wettzell.de

Scherneck,

Hans-Georg

Onsala Space Observatory Sweden hans-georg.scherneck@chalmers.se

Schl ̈uter,

Wolfgang

Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany Wolfgang.Schl ̈uter@bkg.bund.de

Schuh, Harald Institute of Geodesy and

Geophysics

Austria harald.schuh@tuwien.ac.at

Schupler, Bruce Honeywell TSI USA bruce.schupler@honeywell-tsi.com

Schwarz, Walter Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany walter.schwarz@bkg.bund.de

Schwegmann,

Wolfgang

Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany wolfgang.schwegmann@bkg.bund.de

Sciarretta,

Cecilia

Telespazio SpA Italy cecilia@asi.it

Searle, Anthony Natural Resources Canada Canada asearle@NRCan.gc.ca

Sekido, Mamoru National Institute of Information

and Communications Technology

Japan sekido@nict.go.jp

Shao, Minghui Urumqi Astronomical

Observatory

China nanshan@ms.xjb.ac.cn

Shibuya, Kazuo National Institute of Polar

Research

Japan shibuya@nipr.ac.jp

Shigematsu,

Hiromi

Geographical Survey Institute Japan vlbi@gsi.go.jp

Shishikin,

Alexandr

Institute of Applied Astronomy Russia

Shu, Fengchun Shanghai Astronomical

Observatory

China sfc@center.shao.ac.cn

Skurikhina,

Elena

Institute of Applied Astronomy Russia sea@quasar.ipa.nw.ru

Smolentsev,

Sergey

Institute of Applied Astronomy Russia smolen@isida.ipa.rssi.ru

Smythe, Dan MIT Haystack Observatory USA dsmythe@haystack.mit.edu

Sobarzo, Sergio TIGO/Universidad de

Concepci ́on

Chile sergio.sobarzo@tigo.cl

Sokolova, Yulia Pulkovo Observatory Russia s0lei@yandex.ru

Sousa, Don MIT Haystack Observatory USA dsousa@haystack.mit.edu

Sovers, Ojars Remote Sensing Analysis Inc. USA ojars@rsasys.com

Stanghellini,

Carlo

Istituto di Radioastronomia

INAF

Italy c.stanghellini@ira.inaf.it

Steppe, Alan Jet Propulsion Laboratory USA as@logos.jpl.nasa.gov

Surkis, Igor Institute of Applied Astronomy Russia surkis@isida.ipa.rssi.ru

304 IVS 2007 Annual Report
Associate Members

Name Institution Country E-mail

Takashima,

Kazuhiro

Geographical Survey Institute Japan takasima@gsi.go.jp

Takiguchi,

Hiroshi

National Institute of Information

and Communications Technology

Japan htaki@nict.go.jp

Tamura,

Yoshiaki

National Astronomical

Observatory of Japan

Japan tamura@miz.nao.ac.jp

Tangen, Leif

Morten

Norwegian Mapping Authority Norway leif.morten.tangen@statkart.no

Tanimoto,

Daisuke

Geographical Survey Institute Japan vlbi@gsi.go.jp

Tanir, Emine Institute of Geodesy and

Geophysics

Austria etanir@mars.hg.tuwien.ac.at

Tao, An Shanghai Astronomical

Observatory

China antao@center.shao.ac.cn

Tateyama,

Claudio

Centro de R ́adio Astronomia e

Aplica ̧c ̃oes Espaciais

Brazil tateyama@craam.mackenzie.br

Teke, Kamil Institute of Geodesy and

Geophysics

Austria kteke@mars.hg.tuwien.ac.at

Tesmer, Volker Deutsches Geod ̈atisches

Forschungsinstitut

Germany tesmer@dgfi.badw.de

Thomas,

Cynthia

NVI, Inc./GSFC USA cynthia.c.thomas@nasa.gov

Thorandt,

Volkmar

Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany volkmar.thorandt@bkg.bund.de

Thornton,

Bruce

U. S. Naval Observatory USA blt@casa.usno.navy.mil

Titov, Oleg Geoscience Australia Australia Oleg.Titov@ga.gov.au

Titus, Mike MIT Haystack Observatory USA mtitus@haystack.mit.edu

Todorova, Sonja Institute of Geodesy and

Geophysics

Austria stodo@mars.hg.tuwien.ac.at

Tomasi, Paolo Istituto di Radioastronomia

INAF

Italy tomasi@ira.inaf.it

Trigilio,

Corrado

Istituto di Radioastronomia

INAF

Italy ctrigilio@oact.inaf.it

Tsutsumi,

Masanori

National Institute of Information

and Communications Technology

Japan tsutsumi@nict.go.jp

Tuccari, Gino Istituto di Radioastronomia

INAF

Italy g.tuccari@ira.inaf.it

Ullrich, Dieter Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany dieter.ullrich@bkg.bund.de

Vennebusch,

Markus

Institute for Geodesy and

Geoinformation of the University

of Bonn

Germany vennebusch@uni-bonn.de

Venturi, Tiziana Istituto di Radioastronomia

INAF

Italy t.venturi@ira.inaf.it

IVS 2007 Annual Report 305
Associate Members

Name Institution Country E-mail

Verdugo, Carlos TIGO/Universidad de

Concepci ́on

Chile carlos.verdugo@tigo.cl

Vespe,

Francesco

Agenzia Spaziale Italiana Italy vespe@asi.it

Vityazev,

Veniamin

Astronomical Institute of

St.-Petersburg

Russia vityazev@list.ru

Volvach,

Alexandr

Crimean Astrophysical

Observatory

Ukraine volvach@crao.crimea.ua

Vytnov,

Alexander

Institute of Applied Astronomy Russia vytnov@isida.ipa.rssi.ru

Wang, Guangli Shanghai Astronomical

Observatory

China wgl@center.shao.ac.cn

Wang, Jinqing Shanghai Astronomical

Observatory

China jqwang@center.shao.ac.cn

Wang, Lingling Shanghai Astronomical

Observatory

China llwang@center.shao.ac.cn

Wang, Na Urumqi Astronomical

Observatory

China Na.wang@ms.xjb.ac.cn

Wang, Weixia Urumqi Astronomical

Observatory

China wangwx@ms.xjb.ac.cn

Wei, Wenren Shanghai Astronomical

Observatory

China wwr@center.shao.ac.cn

Whitney, Alan MIT Haystack Observatory USA awhitney@haystack.mit.edu

Wojdziak,

Reiner

Bundesamt f ̈ur Kartographie

und Geod ̈asie

Germany reiner.wojdziak@bkg.bund.de

Wooden,

William

U. S. Naval Observatory USA wooden.william@usno.navy.mil

Xue, Zhouhe Shanghai Astronomical

Observatory

China zhxue@center.shao.ac.cn

Yatskiv,

Yaroslav

Main Astronomical Observatory Ukraine yatskiv@mao.kiev.ua

Ye, Shuhua Shanghai Astronomical

Observatory

China ysh@center.shao.ac.cn

Yusup, Aili Urumqi Astronomical

Observatory

China aliyu@ms.xjb.ac.cn

Zeitlh ̈ofler,

Reinhard

Fundamentalstation Wettzell Germany zeitlhoefler@fs.wettzell.de

Zhang, Ali Urumqi Astronomical

Observatory

China zhangal@uao.ac.cn

Zhang, Jin Urumqi Astronomical

Observatory

China zhangj@ms.xjb.ac.cn

Zhang,

Xiuzhong

Shanghai Astronomical

Observatory

China xzhang@shao.ac.cn

Zhao, Rongbing Shanghai Astronomical

Observatory

China zhaorb@center.shao.ac.cn

306 IVS 2007 Annual Report
Associate Members

Name Institution Country E-mail

Zheng, Weimin Shanghai Astronomical

Observatory

China zhwm@shao.ac.cn

Zhou, Ruixian Shanghai Astronomical

Observatory

China zrx@center.shao.ac.cn

IVS 2007 Annual Report 307
IVS Permanent Components

IVS Permanent Components

(listed by types, within types alphabetical by component name)

Network Stations

Component Name Sponsoring Organization Country

Radioastronomical Observatory Badary Institute of Applied Astronomy RAS Russia

Fortaleza, Radio Observat ́orio Espacial do

Nordeste (ROEN)

Centro de R ́adio Astronomia e Aplica ̧c ̃oes

Espaciais

Brazil

Goddard Geophysical and Astronomical

Observatory

NASA Goddard Space Flight Center USA

Hartebeesthoek Radio Astronomy

Observatory

Foundation for Research and Development South Africa

Hobart, Mt. Pleasant Radio Observatory University of Tasmania Australia

Kashima 34m National Institute of Information and

Communications Technology (NICT)

Japan

Key Stone Project Kashima 11m National Institute of Information and

Communications Technology (NICT)

Japan

Key Stone Project Koganei 11m National Institute of Information and

Communications Technology (NICT)

Japan

Kokee Park Geophysical Observatory National Earth Orientation Service

(NEOS)

USA

Matera Agenzia Spaziale Italiana (ASI) Italy

Medicina Istituto di Radioastronomia Italy

Mizusawa 10m National Astronomical Observatory of

Japan (NAOJ)

Japan

Noto (Sicily) Istituto di Radioastronomia Italy

Ny- ̊Alesund Geodetic Observatory Norwegian Mapping Authority Norway

ERS/VLBI Station O’Higgins Bundesamt f ̈ur Kartographie und

Geod ̈asie (BKG)

Germany

Onsala Space Observatory Chalmers University of Technology Sweden

Seshan Joint Laboratory for Radio Astronomy

(JLRA), CAS and Shanghai Observatory,

CAS

China

Simeiz Laboratory of Radioastronomy of Crimean

Astrophysical Observatory

Ukraine

Svetloe Radio Astronomy Observatory Institute of Applied Astronomy RAS Russia

JARE Syowa Station National Institute of Polar Research Japan

308 IVS 2007 Annual Report
IVS Permanent Components

Transportable Integrated Geodetic

Observatory (TIGO)

Universidad de Concepci ́on (UdeC),

Universidad del B ́ıo B ́ıo (UBB), Instituto

Geogr ́afico Militar (IGM), Bundesamt f ̈ur

Kartographie und Geod ̈asie (BKG)

Germany,

Chile

Tsukuba VLBI Station Geographical Survey Institute Japan

Nanshan VLBI Station Chinese Academy of Sciences China

Westford Antenna, Haystack Observatory NASA Goddard Space Flight Center USA

Fundamentalstation Wettzell Bundesamt f ̈ur Kartographie und Geod ̈asie

(BKG) and Forschungseinrichtung

Satellitengeod ̈asie der Technischen

Universit ̈at M ̈unchen (FESG)

Germany

Observat ́orio Astron ́omico Nacional -

Yebes

Instituto Geogr ́afico Nacional Spain

Radioastronomical Observatory

Zelenchukskaya

Institute of Applied Astronomy RAS Russia

Operation Centers

Component Name Sponsoring Organization Country

Institut f ̈ur Geod ̈asie und Geoinformation

(IGGB)

Universit ̈at Bonn Germany

CORE Operation Center NASA Goddard Space Flight Center USA

NEOS Operation Center National Earth Orientation Service

(NEOS)

USA

Correlators

Component Name Sponsoring Organization Country

Astro/Geo Correlator at MPI Bundesamt f ̈ur Kartographie und

Geod ̈asie and Institut f ̈ur Geod ̈asie und

Geoinformation der Universit ̈at Bonn

Germany

MIT Haystack Correlator NASA Goddard Space Flight Center USA

Institute of Applied Astronomy Correlator Institute of Applied Astronomy Russia

National Institute of Information and

Communications Technology (NICT)

National Institute of Information and

Communications Technology (NICT)

Japan

Tsukuba VLBI Center Geographical Survey Institute Japan

Washington Correlator National Earth Orientation Service

(NEOS)

USA

IVS 2007 Annual Report 309
IVS Permanent Components

Data Centers

Component Name Sponsoring Organization Country

BKG, Leipzig Bundesamt f ̈ur Kartographie und Geod ̈asie Germany

Crustal Dynamics Data Information

System (CDDIS)

NASA Goddard Space Flight Center USA

GeoDAF Agenzia Spaziale Italiana (ASI) Italy

Italy INAF Istituto di Radioastronomia INAF Italy

National Institute of Information and

Communications Technology

National Institute of Information and

Communications Technology

Japan

Observatoire de Paris Observatoire de Paris France

Analysis Centers

Component Name Sponsoring Organization Country

Astronomical Institute of St.-Petersburg

University

Astronomical Institute of St.-Petersburg

University

Russia

Geoscience Australia Geoscience Australia Australia

Observatoire de Bordeaux Observatoire de Bordeaux France

Centro di Geodesia Spaziale (CGS) Agenzia Spaziale Italiana Italy

DGFI Deutsches Geod ̈atisches Forschungsinstitut Germany

Forsvarets forskningsinstitutt (FFI) Norwegian Defence Research

Establishment

Norway

IGGB-BKG Analysis Center Institut f ̈ur Geod ̈asie und Geoinformation

der Universit ̈at Bonn and Bundesamt f ̈ur

Kartographie und Geod ̈asie

Germany

Goddard Space Flight Center NASA Goddard Space Flight Center USA

Haystack Observatory Haystack Observatory and NASA

Goddard Space Flight Center

USA

Institute of Applied Astronomy Analysis

Center

Institute of Applied Astronomy Russia

Institute of Geodesy and Geophysics

(IGG)

Institute of Geodesy and Geophysics

(IGG) of the University of Technology,

Vienna

Austria

Italy INAF Istituto di Radioastronomia INAF Italy

Jet Propulsion Laboratory Jet Propulsion Laboratory USA

Main Astronomical Observatory Main Astronomical Observatory, National

Academy of Sciences, Kiev

Ukraine

National Astronomical Observatory of

Japan

National Astronomical Observatory of

Japan

Japan

310 IVS 2007 Annual Report
IVS Permanent Components

National Institute of Information and

Communications Technology

National Institute of Information and

Communications Technology

Japan

Observatoire de Paris Observatoire de Paris France

Onsala Space Observatory Chalmers University of Technology Sweden

Pulkovo Observatory Pulkovo Observatory Russia

Shanghai Observatory Shanghai Observatory, Chinese Academy

of Sciences

China

U. S. Naval Observatory Analysis Center U. S. Naval Observatory USA

U. S. Naval Observatory Analysis Center

for Source Structure

U. S. Naval Observatory USA

Technology Development Centers

Component Name Sponsoring Organization Country

Canadian VLBI Technology Development

Center

CRESTech, NRCan, DRAO, CSA Canada

Forsvarets forskningsinstitutt (FFI) Norwegian Defence Research

Establishment

Norway

Goddard Space Flight Center NASA Goddard Space Flight Center USA

Haystack Observatory Haystack Observatory and NASA

Goddard Space Flight Center

USA

Institute of Applied Astronomy

Technology Development Center

Institute of Applied Astronomy Russia

National Institute of Information and

Communications Technology

National Institute of Information and

Communications Technology

Japan

Onsala Space Observatory Chalmers University of Technology Sweden

IVS 2007 Annual Report 311
Contributing Institutions

Addresses of Institutions of Authors Contributing to this Report

(listed alphabetically by country)

Geoscience Australia

PO Box 378

Canberra ACT

2601

Australia

http://ga.gov.au

University of Tasmania, Geoscience Australia

School of Mathematics and Physics

University of Tasmania

Private Bag 37

Hobart 7001

Australia

http://www.phys.utas.edu.au/physics

Institute of Geodesy and Geophysics, Vienna University of Technology

Gusshausstrasse 27-29

1040 Vienna

Austria

http://www.hg.tuwien.ac.at

CRAAM, Universidade Presbiteriana Mackenzie, S ̃ao Paulo

CRAAM

Instituto Presbiteriano Mackenzie

Rua da Consola ̧c ̃ao 896

01302-907 S ̃ao Paulo

SP

Brazil

http://www.craam.mackenzie.br

Instituto Nacional de Pesquisas Espaciais

Estrada do Fio 6000

Bairro Tupui ́u

61760-000 Eus ́ebio

CE

Brazil

http://www.roen.inpe.br

Geodetic Survey Division, Natural Resources Canada

615 Booth St.

Ottawa

Ontario

Canada K1A 0E9

http://www.geod.nrcan.gc.ca

312 IVS 2007 Annual Report
Contributing Institutions

Bundesamt f ̈ur Kartographie und Geod ̈asie - TIGO

Casilla 4036

Correo 3

Concepci ́on

Chile

http://www.bkg.de

Universidad de Concepci ́on - TIGO

Concepci ́on

Chile

http://www.udec.cl

Shanghai Astronomical Observatory, Chinese Academy of Sciences

80 Nandan Road

Shanghai 200030

People’s Republic of China

http://www.shao.ac.cn/english.htm

Urumqi Observatory, NAO, CAS

40-5 South Beijing Road

Urumqi

Xinjiang Uygur Autonomous Region

830011

China

http://www.uao.ac.cn

Observatoire de Bordeaux

BP 89

33270 Floirac

France

http://www.obs.u-bordeaux1.fr

Observatoire de Paris, SYRTE, CNRS/UMR8630

61 avenue de l’Observatoire

F-75014 Paris

France

http://www.obspm.fr

http://ivsopar.obspm.fr

Bundesamt f ̈ur Kartographie und Geod ̈asie

Karl-Rothe-Strasse 10-14

04105 Leipzig

Germany

http://www.bkg.bund.de

Deutsches Geod ̈atisches Forschungsinstitut (DGFI)

Alfons-Goppel-Strasse 11

80539 M ̈unchen

Germany

http://www.dgfi.badw.de

IVS 2007 Annual Report 313
Contributing Institutions

Fundamentalstation Wettzell

Bundesamt f ̈ur Kartographie und Geod ̈asie and

Forschungseinrichtung Satellitengeod ̈asie (FESG)

Sackenrieder Str. 25.

D-93444 K ̈otzting

Germany

http://www.fs.wettzell.de

Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn

Nussallee 17

53115 Bonn

Germany

http://vlbi.geod.uni-bonn.de

Max-Planck-Institute for Radioastronomy

Auf dem H ̈ugel 69

53121 Bonn

Germany

http://www.mpifr-bonn.mpg.de

Agenzia Spaziale Italiana

Centro di Geodesia Spaziale

C.P. Aperta

Ctr.da Terlecchia

75100 Matera

Italy

http://www.asi.it

Istituto di Radioastronomia–Bologna

Via P. Gobetti 101

40129 Bologna

Italy

http://www.ira.inaf.it

DISTART - University of Bologna

Viale Risorgimento2

40136 Bologna

Italy

http://www.distart.ing.unibo.it

Istituto di Radioastronomia, Medicina

C.P. 14

40060 Villafontana

Bologna

Italy

http://www.med.ira.inaf.it

314 IVS 2007 Annual Report
Contributing Institutions

Istituto di Radioastronomia INAF, Stazione VLBI di Noto

C.P. 161

I-96017 Noto SR

Italy

http://www.noto.ira.inaf.it

Geographical Survey Institute, Japan

Code 305-0811

Kitasato 1-ban

Tsukuba

Ibaraki Pref.

Japan

http://vldb.gsi.go.jp/sokuchi/vlbi/english

Mizusawa VERA Observatory

2-12 Hoshigaoka-cho

Mizusawa-ku

Oshu-shi

Iwate-ken 023-0861

Japan

http://www.miz.nao.ac.jp

National Institute of Information and Communications Technology

893-1 Hirai

Kashima

Ibaraki 314-0012

Japan

http://www2.nict.go.jp/w/w114/stsi/index e.html

National Institute of Polar Research

1-9-10

Kaga

Itabashi-ku

Tokyo 173-8515

Japan

http://www.nipr.ac.jp/welcome.html

Forsvarets forskningsinstitutt (FFI) (Norwegian Defence Research Establishment)

FFI/E

Box 25

2007 Kjeller

Norway

http://www.ffi.no/

Geodetic Institute, Norwegian Mapping Authority

Kartverksveien

Hønefoss

Norway

http://www.statkart.no

IVS 2007 Annual Report 315
Contributing Institutions

Central Astronomical Observatory at Pulkovo of the Russian Academy of Sciences

Pulkovskoe Ch. 65/1

St. Petersburg

196140

Russia

http://www.gao.spb.ru

Institute of Applied Astronomy of Russian Academy of Sciences (IAA)

nab. Kutuzova 10

St. Petersburg

191187

Russia

http://www.ipa.nw.ru

HartRAO, NRF

PO Box 443

Krugersdorp

1740

South Africa

http://www.hartrao.ac.za

Instituto Geogr ́afico Nacional

Calle General Iba ̃nez de Ibero 3

E-28003 Madrid

Spain

http://www.ign.es/

Observat ́orio Astron ́omico Nacional

Apartado 112

E-28803 Alcal ́a de Henares

Spain

http://www.oan.es/

Onsala Space Observatory (OSO)

SE-439 92

Onsala

Sweden

http://www.oso.chalmers.se

Main Astronomical Observatory, National Academy of Sciences of Ukraine

Main Astronomical Observatory

27 Akademika Zabolotnoho St.

Kiev

03680

Ukraine

http://www.mao.kiev.ua

316 IVS 2007 Annual Report
Contributing Institutions

Radio Astronomy Lab of Crimean Astrophysical Observatory

RT-22

Katsively

Yalta Crimea 98688

Ukraine

http://www.crao.crimea.ua

Jet Propulsion Laboratory, California Institute of Technology

Mail Stop 238-600

4800 Oak Grove Dr.

Pasadena, California 91109

USA

http://www.jpl.nasa.gov

Kokee Park Geophysical Observatory

Kokee State Park

P.O. Box 538

Waimea, Hawaii 96796

USA

MIT Haystack Observatory

Off Route 40

Westford, MA 01886

USA

http://www.haystack.mit.edu

NASA Goddard Space Flight Center

Code 698

Greenbelt, MD 20771

USA

http://lupus.gsfc.nasa.gov

United States Naval Observatory

3450 Massachusetts Avenue NW

Washington, DC 20392

USA

http://www.usno.navy.mil/

U.S. Naval Observatory, Flagstaff Station

10391 West Naval Observatory Rd.

Flagstaff, AZ 86001

USA

http://www.nofs.navy.mil

IVS 2007 Annual Report 317
List of Acronyms

List of Acronyms

AAS American Astronomical Society

ACF AutoCorrelation Function

ACU Antenna Control Unit

ADB Analog to Digital Board

ADC Analog to Digital Converter

AER Atmospheric and Environmental Research, Inc. (USA)

AES Advanced Engineering Services Co., Ltd (Japan)

AGN Active Galactic Nuclei

AIPS Astronomical Image Processing System

AOG Auxilliary Output Generator

APSG Asia-Pacific Space Geodynamics program

APT Asia Pacific Telescope

ARIES Astronomical Radio Interferometric Earth Surveying program

ASI Agenzia Spaziale Italiana (Italian Space Agency) (Italy)

ATM Asynchronous Transfer Mode

ATNF Australia Telescope National Facility (Australia)

A-WVR Advanced Water Vapor Radiometer

BBC Base Band Converter

BdRAO Badary Radio Astronomical Observatory (Russia)

BIPM Bureau Internacional de Poids et Mesures (France)

BKG Bundesamt f ̈ur Kartographie und Geod ̈asie (Germany)

BMC Basic Module of Correlator

BWG Beam Waveguide

CARAVAN Compact Antenna of Radio Astronomy for VLBI Adapted Network (Japan)

CAS Chinese Academy of Sciences (China)

CAY Centro Astron ́omico de Yebes (Spain)

CDDIS Crustal Dynamics Data Information System (USA)

CDP Crustal Dynamics Project

CGS Centro di Geodesia Spaziale (Italy)

CIB Correlator Interface Board

CIP Celestial Intermediate Pole

CNES Centre National d’Etudes Spatiales (France)

CNRS Centre National de la Recherche Scientifique (France)

CNS Communication, Navigation and Surveillance systems, Inc. (USA)

CODA Correlator Output Data Analyzer

CORE Continuous Observations of the Rotation of the Earth

CPO Celestial Pole Offset

CRAAE Centro de R ́adio Astronomia e Aplica ̧c ̃oes Espaciais (Brazil)

CRAAM Centro de R ́adio-Astronomia e Astrof ́ısica Mackenzie (Brazil)

CrAO Crimean Astrophysical Observatory (Ukraine)

CRESTech Centre for Research in Earth and Space Technology (Canada)

CRF Celestial Reference Frame

318 IVS 2007 Annual Report
List of Acronyms

CRL Communications Research Laboratory (now NICT) (Japan)

CSA Canadian Space Agency (Canada)

CSIR Council for Scientific and Industrial Research (South Africa)

CSRIFS Combined Square Root Information Filter and Smoother

CTVA Canadian Transportable VLBI Antenna

DAR Data Acquisition Rack

DAS Data Acquisition System

DBBC Digital Base Band Converter

DBE Digital BackEnd

∆DOR Delta Differenced One-way Range

DGFI Deutsches Geod ̈atisches ForschungsInstitut (Germany)

DISTART Dipartimento di Ingegneria delle Strutture, dei Trasporti, delle Acque, del Rilevamento del Territorio (Italy)

DLR Deutsches Zentrum f ̈ur Luft- und Raumfahrt (German Aerospace Center)

DOM Data Output Module

DORIS Doppler Orbitography by Radiopositioning Integrated on Satellite

DR Dichroic Reflector

DRAO Dominion Radio Astrophysical Observatory (Canada)

DSN Deep Space Network

DSS Deep Space Station

DVLBI Differential VLBI

ECMWF European Centre for Medium-Range Weather Forecasts

EGU European Geosciences Union

ENVISAT ENVIronmental SATellite

EOP Earth Orientation Parameters

EOP-PC Earth Orientation Parameter Product Center (France)

ERP Earth Rotation Parameters

ETSIT Escuela T ́ecnica Superior de Ingenieros de Telecomunicaci ́on

EUREF EUropean REFerence Frame

EVGA European VLBI for Geodesy and Astrometry

EVLA Expanded Very Large Array

e-VLBI Electronic VLBI

EVN European VLBI Network

EXPReS Express Production Real-time e-VLBI Service

FAGS Federation of Astronomical and Geophysical data analysis Services

FCN Free Core Nutation

FESG Forschungseinrichtung Satellitengeod ̈asie/Technical University of Munich (Germany)

FFI Forsvarets ForskningsInstitutt (Norwegian Defence Research Establishment) (Norway)

FITS Flexible Image Transport System

FPDP Front Panel Data Port

FS Field System

FTP File Transfer Protocol

FWF Fonds zur F ̈orderung der wissenschaftlichen Forschung (Austrian Science Fund)

IVS 2007 Annual Report 319
List of Acronyms

GA Geoscience Australia (formerly AUSLIG) (Australia)

GAPE Great Alaska and Pacific Experiment

GARNET GSI Advanced Radiotelescope NETwork (Japan)

GARS German Antarctic Receiving Station (Germany)

GEMD Geospatial and Earth Monitoring Division (Australia)

GeoDAF Geodetic Data Archiving Facility (Italy)

GEX Giga-bit series VLBI EXperiment

GFZ GeoForschungsZentrum (Germany)

GGAO Goddard Geophysical and Astronomical Observatory (USA)

GGOS Global Geodetic Observing System

GGP Global Geodynamics Project

GINS G ́eod ́esie par Int ́egrations Num ́eriques Simultan ́ees

GISTM GPS Ionospheric Scintillation and TEC Monitor

GIUB Geodetic Institute of the University of Bonn (now IGGB) (Germany)

GLONASS GLObal NAvigation Satellite System (Russia)

GNSS Global Navigation Satellite Systems

GPS Global Positioning System

GREF German GPS REFerence network

GRGS Groupe de Recherches de G ́eod ́esie Spatiale (France)

GSD Geodetic Survey Division of Natural Resources Canada (Canada)

GSFC Goddard Space Flight Center (USA)

GSI Geographical Survey Institute (Japan)

HEMT High Electron Mobility Transistor

HPBW Half Power Beam Width

HSI High Speed Input bus

HSIR High Speed Input Replicated bus

HTS High Temperature Superconductor

HTSI Honeywell Technology Solutions Incorporated (USA)

IAA Institute of Applied Astronomy (Russia)

IAG International Association of Geodesy

IAU International Astronomical Union

ICRF International Celestial Reference Frame

IERS International Earth Rotation and Reference Systems Service

IF Intermediate Frequency

IGFN Italian Space Agency GPS Fiducial Network (Italy)

IGG Institute of Geodesy and Geophysics (Austria)

IGGB Institut f ̈ur Geod ̈asie und Geoinformation der Universit ̈at Bonn (Germany)

IGM Instituto Geogr ́afico Militar (Chile)

IGN Instituto Geogr ́afico Nacional (Spain)

IGS International GNSS Service

IISGEO International Institute for Space Geodesy and Earth Observation

ILRS International Laser Ranging Service

INAF Istituto Nazionale di Astrofisica (Italy)

INGV Institute of Geophysics and Volcanology (Italy)

INPE Instituto Nacional de Pesquisas Espaciais (Brazil)

320 IVS 2007 Annual Report
List of Acronyms

IP Internet Protocol

IRA Istituto di RadioAstronomia (Italy)

IRIS International Radio Interferometric Surveying

ISAS Institute of Space and Astronautical Science (Japan)

ISBN International Standard Book Number

ISV Instantaneous State Vector

ITRF International Terrestrial Reference Frame

IUGG International Union of Geodesy and Geophysics

IVOA International Virtual Observatory Alliance

IVS International VLBI Service for Geodesy and Astrometry

JADE JApanese Dynamic Earth observation by VLBI

JARE Japanese Antarctic Research Expedition (Japan)

JAXA Japan Aerospace Exploration Agency (Japan)

JGN Japan Gigabit Network (Japan)

JIVE Joint Institute for VLBI in Europe

JLRA Joint Laboratory for Radio Astronomy (China)

JMA Japan Meteorological Agency (Japan)

JPL Jet Propulsion Laboratory (USA)

JSPS Japanese Society for the Promotion of Science (Japan)

KARAT KAshima RAy-tracing Tools (Japan)

KASI Korea Astronomy and Space Science Institute (Korea)

KAT Karoo Array Telescope (South Africa)

KPGO Kokee Park Geophysical Observatory (USA)

KSP KeyStone Project (Japan)

KSRC Kashima Space Research Center (Japan)

KVN Korean VLBI Network

LBA Long Baseline Array (Australia)

LD Laser Diode

LIEF Large Infrastructure and Equipment Funding

LLR Lunar Laser Ranging

LNA Low Noise Amplifier

LO Local Oscillator

LOD Length Of Day

LSB Lower Side Band

LSM Least Squares Method

MAO Main Astronomical Observatory (Ukraine)

MARBLE Multiple Antenna Radio-interferometry for Baseline Length Evaluation

MIT Massachusetts Institute of Technology (USA)

MLRO Matera Laser Ranging Observatory (Italy)

MOBLAS MOBile LASer

MODEST MODel and ESTimate

MPI Max-Planck-Institute (Germany)

MPIfR Max-Planck-Institute for Radioastronomy (Germany)

MTLRS Modular Transportable Laser Ranging System

NAO National Astronomical Observatories (China)

IVS 2007 Annual Report 321
List of Acronyms

NAOJ National Astronomical Observatory of Japan (Japan)

NASA National Aeronautics and Space Administration (USA)

NCRIS National Collaborative Research Infrastructure Strategy (Australia)

NEOS National Earth Orientation Service (USA)

NetCDF Network Common Data Form

NGS National Geodetic Survey (USA)

NICT National Institute of Information and Communications Technology (Japan)

NIPR National Institute of Polar Research (Japan)

NMA Norwegian Mapping Authority (Norway)

NMF Niell Mapping Function

NNR No-Net-Rotation

NNT No-Net-Translation

NOAA National Oceanic and Atmospheric Administration (USA)

NOFS U.S. Naval Observatory Flagstaff Station (USA)

NORAD North American Aerospace Defense Command

NRAO National Radio Astronomy Observatory (USA)

NRCan Natural Resources Canada (Canada)

NTT Nippon Telegraph and Telephone Corporation (Japan)

NVI NVI, Inc. (USA)

NWP Numerical Weather Prediction

OAN Observatorio Astron ́omico Nacional (Spain)

OCA Observatoire de la Cˆote d’Azur (France)

OPAR Observatoire de Paris (France)

OPC (IVS) Observing Program Committee

OS Operating System

OSO Onsala Space Observatory (Sweden)

PARNASSUS Processing Application in Reference to NICT’s Advanced Set of Softwares Usable

for Synchronization

PCAL Phase CALibration

PFB Polyphase Filter Bank

PNR Peak to Noise Ratio

POLARIS POLar motion Analysis by Radio Interferometric Surveying

PPP Precise Point Positioning

PRARE Precise RAnge and Range-rate Equipment

QRHA Quad-Ridge Horn Antenna

QZSS Quasi Zenith Satellite System (Japan)

RAS Russian Academy of Sciences (Russia)

RDV Research and Development sessions using the VLBA

RFI Radio Frequency Interference

ROEN R ́adio-Observat ́orio Espacial do Nordeste (Brazil)

RRFID Radio Reference Frame Image Database

SATA Serial Advanced Technology Attachment

SDK Software Development Kit

SDSS Signal Distribution and Synchronization System

SEFD System Equivalent Flux Density

322 IVS 2007 Annual Report
List of Acronyms

SHAO Shanghai Astronomical Observatory (China)

SINEX Solution INdependent EXchange format

SKA Square Kilometer Array

SLR Satellite Laser Ranging

SPEED Short Period and Episodic Earth rotation Determination

SRT Sardinia Radio Telescope (Italy)

SRTM Shuttle Radar Topography Mission

SSA Singular Spectrum Analysis

SSAI Science Systems and Applications, Inc. (USA)

STEREO Solar TErrestrial RElations Observatory

SvRAO Svetloe Radio Astronomical Observatory (Russia)

SWT SW Technology (USA)

TAC Totally Accurate Clock

TANAMI Tracking Active galactic Nuclei with Australia Milliarcsecond Interferometry (Australia)

TAO Telecommunications Advanced Organization (Japan)

TDC Technology Development Center

TEC Total Electron Content

TEMPO Time and Earth Motion Precision Observations

TLE Two Line Elements

TLRS Transportable Laser Ranging System

TOW Technical Operations Workshop

TRF Terrestrial Reference Frame

TTW TWIN-Telescope Wettzell (Germany)

UBB Universidad del B ́ıo B ́ıo (Chile)

UD Upper Diagonal

UDC Up-Down Converter

URSI Union Radio-Scientifique Internationale

USB Upper Side Band

USNO United States Naval Observatory (USA)

UT Universal Time

UT1 Universal Time

UTAS University of TASmania (Australia)

UTC Coordinated Universal Time

VC Video Converter

VCS VLBA Calibrator Survey

VDBE VLBA Digital BackEnd

VERA VLBI Exploration of Radio Astrometry

VLA Very Large Array (USA)

VLBA Very Long Baseline Array (USA)

VLBI Very Long Baseline Interferometry

VMF Vienna Mapping Functions

VO Virtual Observatory

VSI VLBI Standard Interface

VSI-H VLBI Standard Interface Hardware

IVS 2007 Annual Report 323
List of Acronyms

VSOP VLBI Space Observatory Program

VSSP Versatile Scientific Sampling Processor

VTRF VLBI Terrestrial Reference Frame

WACO WAshington COrrelator (USA)

WVR Water Vapor Radiometer

WWW World Wide Web

XDM eXperimental Development Model

ZcRAO Zelenchukskaya Radio Astronomical Observatory (Russia)

ZTD Zenith Total Delay

ZWD Zenith Wet Delay

324 IVS 2007 Annual Report

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Standard Form 298 (Rev. 8-98)

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29-04-2008 Technical Publication

International VLBI Service for Geodesy and Astrometry 2007 Annual Report

Dirk Behrend, Karen D. Baver

Goddard Space Flight Center

Greenbelt, MD 20771

2008-

National Aeronautics and Space Administration

Washington, DC 20546-0001

NASA/TP-2008-??????

Unclassified-Unlimited, Subject Category: 46

Report available from the NASA Center for Aerospace Information,7121 Standard Drive, Hanover, MD 21076. (301)621-0390

Dirk Behrend, NVI, Inc.; Karen Baver, NVI, Inc.

This volume of reports is the 2007 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

components of IVS. The 2007 Annual Report documents the work of these IVS components over the period January 1, 2007

through December 31, 2007. The reports document changes, activities, and progress of the IVS. The entire contents of this Annual

Report also appear on the IVS Web site at http://ivscc.gsfc.nasa.gov/publications/ar2007.

Geodesy, astrometry, VLBI, geophysics, Earth orientation, very long baseline interferometry, interferometry, radio astronomy,

geodynamics, reference frames, terrestrial reference frame, celestial reference frame, length of day, Earth system science, Earth

rotation.

Unclassified Unclassified Unclassified Unclassified 324

Dirk Behrend

(301) 614-5939

International VLBI Service for Geodesy and Astrometry

IVS Coordinating Center

NASA Goddard Space Flight Center

Code 698

Greenbelt, MD 20771

http://ivscc.gsfc.nasa.gov

ivscc@ivscc.gsfc.nasa.gov

phone: 301-614-5939

fax: 301-614-6522

IVS 

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