High-speed Korea-Japan Joint VLBI Correlator(KJJVC) development and its current progress

9th ADASS Annual Conference
4-9 Oct., 2009

SeSe-Jin Oh, DukDuk-Gyoo Roh,Roh, JaeJae-Hwan Yeom,Yeom, YongYong-Woo Kang, SunSun-Youp Park,
H. Kobayashi*, N. Kawaguchi*, K. Kawakami**, K. Ozeki**
Ozeki**
KASI, *NAOJ, **Elecs**Elecs

Sapporo, Japan

Abstract
The development of Korea-Japan Joint VLBI Correlator (KJJVC) is being progressed in close cooperation with Korea Astronomy and Space Science Institute and National
Astronomical Observatory of Japan for Korean VLBI Network (KVN), Korea-Japan Joint VLBI Network (KJJVN), East-Asian VLBI Network (EAVN) including VSOP2. KJJVC is ableto perform 8Gbps/station data rate, 16 stations with 8192 output channels. It consists of various playback systems, Raw VLBI Data Buffer (RVDB) system, VLBI Correlation
Subsystem (VCS), Peta-scale Epoch Data Archive (PEDA) system, and control and operation software. In case of playback systems, there are many different type of playback
system in East-Asian VLBI Network as like Mark5B, VERA2000, and K5 system. And RVDB system will be able to play back the observed data to VCS with same time fromvarious playback systems. VCS is a core product in KJJVC for processing the correlation of data. PEDA is massive data storage to save the correlated results from VCS. It canalso support e-VLBI through next generation Gigabit network. The factory and field inspection of VCS was performed and VCS was installed at VLBI Correlator room in June andAugust 2009, respectively. The overall system integration work will be performed until end of 2009. The Korea-Japan Joint Correlation Center will be opened in Korea next year.
In this paper, KJJVC development and its current status will be shown in detail.

VLBI Facility in Asia

Korea-Japan Joint VLBI Correlator (KJJVC)KVN, VERA, CVN, VSOP-2

z Dedicated VLBI networks
9VERA (Since 2002), KVN (From 2008), CVN, VSOP-2(~2013)z Other Radio Telescopes
9Nobeyama 45m, TRAO 14m, Delingha 14m
9Others in many Universities and Institutes

Mark5B
Raw
VLBI
Data
Buffer(RVDB)VERA-2000
K-5

Peta-scale
EpochData
Archive(PEDA)

VLBI
Correlation
Subsystem(VCS)

Optical FiberCorrelator Control & Operation S/WPanorama of KJJVCVLBI Correlation Subsystem(VCS)

RVDB

Simultaneous Multi-Frequency Obs.
– Phase Compensation, mm-VLBI

Mark5B

Other system

PEDA

Dual beam – Phase Compensation,
Differential VLBIeration SW
Control & Op

Next Generation Correlator in East Asia
- Joint Correlator Project between Korea and Japan VLBI Facility in Asiaz MOU between KASI & NAOJ (2005. 7. 7.)¾Development of Korea-Japan Joint VLBI Correlator¾ Common facility of correlation & data centerz Joint Development Project was initiated respectively.
¾ Japan : 5 years from April 2005¾ Korea : renewed succession project, 5 years from Jan. 2006
z The overall system of KJJVC is under way of integration in close cooperation between Korea-Japan andmanufacturer until end of 2009.
z KJJVC would fill the role of heart for East Asian VLBI Network and the Space VLBI with VSOP-2. (East Asia
VLBI Consortium Committee, organized at the EAMA6 meeting on Oct. 2004)z We expect that this project becomes a representative East Asian cooperation in astronomy field. (East AsianCore Observatories Association, organized at Tokyo on Sep. 21, 2005)

Mark5BVERA2000VLBI Correlation Subsystem (VCS)

Main specifications of VCS

Observation Frequency
Largest Baseline LengthMax. Data Output Rate

(VSOP2) 45GHz, 130/86/43/22 GHz+-36,000 km(+-0.12sec)
1.4GBytes/sec

Digitization for each Input
Quantization Levels
Interface
Input Data Rate
Architecture
FFT points

1 Gsps by 2bits/sample
4 levels as 00<01<10<11
VS I-H(32 parallels, 1PPS, VALID, PDATA)
2Gbps/1Gbps
FX type, with FPGA and DSP chips
256k/128k/64k/32k/16k/8k Adjustable

Word length in FFTIntegration period

16+16 bits fixed point for real & imag.
25.6msec-10.24sec

Frequency Binning
Correlation Output Data Interface

1-256 channels bin(2’s powers)
10Gbits Ethernet x 4ea¾Data format adjustment : # of bits per sample, and so on¾Easy synchronization while playback (heterogeneous recorder models)¾Buffering between recorder speed(1 Gbps) and correlation speed(8Gbps)¾Handy switching over to next session¾4 sets RVDB system development were completed and basic
experiments were successfully performed. And RVDB system are alreadyused in Mitaka Real Time Correlator, Japan.

•PEDA (Peta-scale Epoch Data Archive)¾It is able to process Max. data rate of 1.4GB/sec from VCS¾Basic system Architecture : Infiniband¾Max. Capacity : 1~3 PB for 1 year (EAVN, VSOP-2), now we prepared
110TB.
¾This system will adopt CODA file system, which is a modified version ofMitaka FX correlator’s file system.
¾Please refer another POSTER, which will be described in detail.
Auto Corr. Result

Experimental Results

600000500000

VCS, W49N, Auto Corr.
W49N Auto-Corr [Miz]3000001.2e+007

AutoAuto

5e+006[Intgration value][Intgration value]

3e+0062.5e+006

8e+006

1000006e+0060

FX, Cross Corr.
500

4e+0061000

1500

3e+007

1e+0060
1000

2000

3000

4000

5000

6000

7000

8000

1000

2000

3000

[Frq-CH]

5000

6000

1.1e+007

Auto

7000

8000

FX, Auto Corr.

[Intgration value][Intgration value]

6e+0065e+0064e+0063e+0067e+0066e+0063500

Lag domain

1000

3000

4000

5000

6000

7000

VERA2K #1

PEDA System v1
Software Developments

Exp.
Debug …

4000

5000

6000

1.5e+006

1e+006500000

0
2000

3000

4000
[Frq-CH]

http://www.nao.ac.jp05000

6000

7000

1000

2000

3000

4000

5000

6000

70008000[Frq-CH]

-40

8000

-2002040[Lag]

FX, Cross Corr.

Amp

2e+0068000

VCS, W49N, Cross Corr.
http://www.kasi.re.kr

7000[Frq-CH]

1000

Cross Phase.

45-4503000

2.5e+006

KJJVC center

8000

-1800
2000

3e+006

VERA2K #2

7000

5e+006

1000

W49N Cros-Corr [Iri - Ishi]

VLBI Correlation Subsystem

6000

-1350

8000

5000

-90

4e+006[Frq-CH][Intgration value]

RVDB #2,3

2000

4000
[Frq-CH]135

1.5e+007

1e+0060

RVDB #4

3000

Cros-Phase [#1 - #3]

1e+006RVDB #1

2000

180

2e+006

Mark5B (4sets)

1000

VCS, OJ287(030126)

4000

1e+0075e+0063e+0062e+006

0

3000

90

[Cros Power]

8e+0062010

2500

2e+0079e+0067e+0062.5e+007

Auto

1e+0078e+006

2009

4000[Frq-CH]

W49N Auto-Corr [Oga]W49N Auto-Corr [Ishi]
9e+006

2000-60000[Phase (deg)]

KJJVC Schedule
2008

0-40000

Lag domain [#1 - #3]

2e+006

2007

20000

-200002e+006
1.5e+006

2006

40000

2000001e+0074e+006

RealImag

60000

4.5e+006

3.5e+006

Cross Corr.

80000

400000

W49N Auto-Corr [Iri]5.5e+006

Cros-Corr [#1 - #3]
100000Auto Corr.
[Intgration value]

16Max. 4 inputs
120 Cross + 16 Auto
2 case (12 + 4, 8 + 8)

Mark5B as int’l consortium member. This is VSI compatible with 1Gbps andconsists of 2(two) 8-pack HDD.
•VERA2000 : DIR2000 is in use extensively at VERA. VERA 2000, which ismodified by DIR1000, will be used for VERA with 1Gbps.
•K5 : which is one another HDD based system for other institutes anduniversity from NiCT, Japan.
•Optical Fiber : Capable of dealing with the full data rate of 8 Gbps.

•RVDB (Raw VLBI Data Buffer)
RVDB# of stations# of Inputs / station
Max. # of Correlations / Input
Subarray constitution• Mark5B : which is widely used in VLBI and KVN participated in developing•To verify the performance of VCS, we conducted
correlation experiments using VERA and JNet data, which
is a spectral line source named as W49N and continuum
source named as OJ287.
•In case of W49N, the results of VCS was compared withMitaka FX correlator.