KVNRecent Progress of Daejeon Correlator

Se-Jin OhDuk-Gyoo Roh, Jae-Hwam Yeom, ChungSik Oh, Jinseung Jung, Dong-Kyu Jung, Youngjoo Yun, A.

Miyazaki, T. Oyama, N. Kawaguchi, H. Kobayashi, K. Shibata,

and staff of Correlator team of KASI/NAOJ

2nd IVTW, ICC Jeju, Korea. 10-12, Oct. 2013

Contents

BackgroundSystem Introduction

Playback System RVDB System VLBI Correlation Subsystem Correlated VLBI Data Buffer(CVDB) Post Processing SW

Recent StatusKJCC OperationExperimental ResultFuture Work

Target Array : EAVN

For KVN, KVN+VERA/JVN, and EAVN. And also for Chinese Space-VLBI

Antenna(s)in the Space

To establish the bigger, more powerful correlator and get the best performance in East Asian VLBI Network, we concluded that KASI & NAOJ join together to develop new Correlator.

MOU between KASI & NAOJ (2005. 7. 7.) Development of Korea-Japan Joint VLBI Correlator, Common facility of correlation & data center

Joint Development Project was initiated respectively.Japan : 5 years from April 2005Korea : 5 years from Jan. 2006

Korea-Japan Joint VLBI Correlator(KJJVC) Development ProjectBackgrounds

Items Specifications

Number of Antennas 16

Number of Inputs / Antenna- Input Interface- Maximum Data Rates

4- 2Gbps VSI-H (32parallels, 64 MHz clk)- Total of 8,192 Mbps

Digitization for Each Inputs- Number of Bits- Quantization Levels- Sampling Rates- Input Bandwidth- Sub-stream Specification

 - 2 bits/sample- 4 levels- 1,024 Msamples/sec- 512 MHz- Logically Associated Sub-streams

Maximum Delay Compensation  (Largest Baseline Length) ±36,000 km

Maximum Fringe Tracking  (Fastest Phase Drift Cancella-tion)

1,075 kHz  

Architecture FX type, with FPGA and DSP chips

Specification (1) of KJJVC

KASI + NAOJ 2006~2010

Items Specifications

FFT Processing- Freq. Resolution- Size of FFT points- Word length in FFT- Scaling- Re-quantization

 - 0.05km/sec @ 22GHz- 256k/128k/64k/32k/16k/8k Adjustable- 20+20 bits fixed point for real & imagi-nary- Yes- 16+16 bits fixed point for real & imagi-nary

△W Correction Yes

Correlations- Number of Correlation Outputs/Input- Total Number of Correlation Out-puts- Polarization Mode  - Data compression(Binning)- Word length- min.  max Integration Time

 - Max. 120 Cross- and 16 Auto-correla-tions- Max. 480 Cross- and 64 Auto-correla-tions- RR or LL ; Full Operation for 16 anten-nas RR and LL ; Full Operation for 16 anten-nas RR, RL, LR and LL : Full Op. for 8 anten-nas- Yes, 8,192 channels / correlation output- 32+32 bits Fixed Point for R & I- 25.6msec ~ 10.24sec

Data Output to Archive (Max.) 1.4 GBytes/sec

Subarray Operation 2 cases (12 + 4, 8 + 8)

Specification (2) of KJJVC

KJJVC Framework

Mark5B

VERA2000

OCTADISK

Optical Fiber

RawVLBIDataBuffer(RVDB)

VLBICorrelationSubsystem(VCS)

CorrelatedVLBIDataBuffer(CVDB)

Correlator Control & Operation S/W

Yellow : NAOJ, Green : KASI

Playback Systems

Mark5B playback VSI compatible : KVN

DIR2000 is in use extensively at VERA. VERA 2000, which is modified by NAOJ according to

DIR1000, used for Playing back DIR2000 tape media for VERA.

OCTADISK : modified using RVDB with 4Gbps recorder/playback developed by NAOJ.

Optical Fiber : Capable of dealing with the full data rate of 8 Gbps.

OCTADISK(VDIF)VERA2000Mark5B

Raw VLBI Data Buffer (RVDB)

Purpose : Adjust data format as like # of bits per sample,

and so on Easily synchronize the data while playback

(heterogeneous recorder models) Maintain the buffering between recorder

speed(1 Gbps) and correlation speed(8 Gbps)

(N. Kawaguchi / NAOJ)

Raw VLBI Data Buffer (RVDB)basic configuration

VSI OpticalAdapter(OCTAVIA)

From Playing Back Units

1Gbps, nominal

10GbE

Sw

itch

2Gbps, nominal OCTADDB

OCTADDB

OCTADDB

OCTADDB

4 D-ports

4 C-ports To CorrelatorInput Ports

OCTADISK

Control PC

VDIF

VLBI Correlation Subsystem (VCS)(2007.8-2009.7)

• 16 Stations, 8Gbps /sta-tion

• Serialized data sub-streams in time domain, and Parallel processing in frequency channels after FFT.

• Full polarization correla-tion is supported (up to 8 stations)

• Two sub-array modes are prepared (12+4 and 8+8).

• Max. data output rate is 1.4GB/sec @ 25.6ms in-tegration

Antenna UnitAntenna Unit Corr & Acu.Unit

CVDB(Correlated VLBI Data Buffer)

Max. data rate : 1.4GB/sec @25.6ms integ.(~10% at average operation)

need to implement massive storage to save the correlation results with four 10GbE of VCS CVDB (specification)

Architecture• Infiniband

Max. Capacity• 1~3 PB for 1 year (EAVN, Space VLBI)• 500 TB at initial phase (KVN, KJJVN)

~119 TB

Post-Processing SW configuration

Developing with Japanese colleagues, NAOJ(CODA) and Kagoshima Univ.(GFS)CODA file system (CCcoda ver2.1), FITSgen

to reduce the developing efforts & cost, and to have compatibility with MTK FX

Recent Status : Hardware(RVDB)

By NAOJ In RVDB system, 3 OCTADDB system changed

to OCTADISK so as to support VERA(JVN) wideband observation, these are now testing in Mitaka.

After completion of test, these will be delivered to KJCC until end of October this year.

2set OCTADISK2 systems were already ordered to manufacturer for supporting VERA wideband data with high speed(over 8 Gbps) recording

Please refer to Kono-san’s presentation in detail on Saturday

Recent Status: Hardware(VCS)

New firmware was installed DC-like component deletion @ band start Phase concentration deletion @ band

start FFT operation : 16bit20bitExperiments of scaling

factor/requantization for FFT were performed, so new reasonable factors were determined.

Correlation is currently conducted using modified firmware as indicated above.

Recent Status: Software

CODAgen/FITSgen By Kan-ya san’s great effort of

Leonid/NAOJ, creating time for CODA F/S was reduced within 3~4 hours for 8hours observation with 16MHz-16stream.

Also creating time for FITS was reduced within 1 hour for 8 hours observation with 16MHz-16stream.

Creating time depends on the observational(correlation) mode.

New Building

East Asia VLBI Research Center(2012.9.13.)

KASI Headquarter @Daejeon

Daejeon Correlator

2012.07~ current

KJCC(Korea-Japan Correlation Center) Operation room

MoA for KJCC joint operation(’11.7.20.)

KJCC - Operation Structure

Executive Board

KVN + VERA(+ EAVN)

Oper. Support Group• KVN

• VERA / JVN

• EAVN

• Mitaka Correlator

Korea-Japan Correlation Center

Project manager 1 , 1

Operation manager 1 , 1

System Engineer 3 , 3

Operator 2 , 6

Data quality analyzer 2 , 4

now future

KASI operates KJCC with supporting operational budget and know-how of NAOJ.

Experimental Results

To adjust the scaling factor, requantization bit position and verify the performance of Daejeon Correlator

Observation Code : r11027b Array : KVN+VERA combined 7stations Observation frequency : 22 GHz Observation time : 9.2hours Correlation mode : C5(16MHz BW, 16stream) Integration time : 1.6384sec

FFT scale factor, Re-quantization

SgrB2M

By S.S. Lee et al

(22GHz)

Correlation(backlog) StatusExp. Object Correlation Status

R11027BKVN+VERA

Evaluation for KJCCFinished In Analyzing

K12098CKVN 4channel simulta-

neous obsFinished In Analyzing

R11025AKVN+VERA

22GHzFinished In Analyzing

R11026AKVN+VERA

43GHzFinished In Analyzing

R12280AKVN+VERA

43GHz surveyFinished In Analyzing

R11088BR11089BR11090BR11091BR11093BR11095B

KVN+VERASgrA* campaign

Finished In Analyzing

R11094A,B

22/43 GHz KVN+VERA Finished In Analyzing

R13082BR13083BR13084BR13085BR13086BR13102A

KVN+VERASgrA* campaign

In progress for corre-lation

Undergoing correla-tion

From 2013,Daejeon correlatoris normally operatingfor C5 mode(16MHz-16channel)

Future plansupporting for other mode(wideband etc)

EAVN evaluation observation 24th Sept. 2013 KVN, VERA, CVN(Shanghai, Kunming, Urumuqi),

JVN ~ 13 stations had been joined These observed data will be correlated by Daejeon

correlator

Until the end of 2013 C2 (128MHz BW, 2streams) C1 (256MHz BW, 1stream) W1 (512MHz BW) Polarization correlation

• Test correlation will be also performed soon or within this year.

Change Tape to Disc @ KJCC/VERA(Planned)

1Gbps80 min.

4Gpbs6 Hours or longer

In VERA, parallel operation of tape and disk are now going on.

VERA2000

OCTADISK