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Recent Progress of Daejeon Correlator Se-Jin Oh Duk-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.
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Recent Progress of DaejeonCorrelatorSe-Jin OhDuk-GyooRoh, Jae-HwamYeom, ChungSik Oh, Jinseung Jung, Dong-Kyu Jung, YoungjooYun, 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 • Background • System Introduction • Playback System • RVDB System • VLBI Correlation Subsystem • Correlated VLBI Data Buffer(CVDB) • Post Processing SW • Recent Status • KJCC Operation • Experimental Result • Future Work
Target Array : EAVN • For KVN, KVN+VERA/JVN, and EAVN. • And also for Chinese Space-VLBI Antenna(s) in the Space
Korea-Japan Joint VLBI Correlator(KJJVC) Development ProjectBackgrounds • 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
Specification (1) of KJJVC KASI + NAOJ 2006~2010
Mark5B Raw VLBI Data Buffer (RVDB) VLBI Correlation Subsystem (VCS) Correlated VLBI Data Buffer (CVDB) VERA2000 OCTADISK Optical Fiber Correlator Control & Operation S/W KJJVC Framework • 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. Mark5B VERA2000 OCTADISK(VDIF)
Raw VLBI Data Buffer (RVDB) (N. Kawaguchi / NAOJ) • 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)
VSI Optical Adapter(OCTAVIA) Raw VLBI Data Buffer (RVDB)basic configuration Control PC ToCorrelator Input Ports 4 C-ports OCTADDB 2Gbps, nominal 10GbE Switch OCTADDB OCTADDB 4 D-ports OCTADDB 1Gbps, nominal FromPlaying BackUnits VDIF OCTADISK
VLBI Correlation Subsystem (VCS)(2007.8-2009.7) Antenna Unit Corr & Acu.Unit Antenna Unit • 16 Stations, 8Gbps /station • Serialized data sub-streams in time domain, and Parallel processing in frequency channels after FFT. • Full polarization correlation 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 integration
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 : 16bit20bit Experiments 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-yasan’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 KASI Headquarter @Daejeon East Asia VLBI Research Center (2012.9.13.)
DaejeonCorrelator 2012.07~ current
KJCC - Operation Structure • KASI operates KJCC with supporting operational budget and know-how of NAOJ. ExecutiveBoard KVN + VERA(+ EAVN) • Oper. Support Group • KVN • VERA / JVN • EAVN • MitakaCorrelator 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
Experimental Results • To adjust the scaling factor, requantization bit position and verify the performance of DaejeonCorrelator • 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
(22GHz) By S.S. Lee et al
Correlation(backlog) Status From 2013, Daejeoncorrelator is normally operating for 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 Daejeoncorrelator • 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) VERA2000 OCTADISK 1Gbps 80 min. 4Gpbs 6 Hours or longer In VERA, parallel operation of tape and disk are now going on.