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E-VLBI Activity in NICT

E-VLBI Activity in NICT. National Institute of Information and Communications Technology (NICT) Kashima Space Research Center M. Sekido, 、 Y. Koyama, M. Kimura, H. Takiguchi, T. Kondo, T. Hobiger, T. Ikeda, H. Harai, M. Hirabaru. E-VLBI Activity in NICT. E-VLBI Project

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E-VLBI Activity in NICT

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  1. E-VLBI Activity in NICT National Institute of Information and Communications Technology (NICT) Kashima Space Research Center M. Sekido,、Y. Koyama, M. Kimura, H. Takiguchi, T. Kondo, T. Hobiger, T. Ikeda, H. Harai, M. Hirabaru

  2. E-VLBI Activity in NICT E-VLBI Project JGN2 Sympo07 Demo: real-time e-VLBI with Haystack Realtime e-VLBI(Kashima,Tsukuba,Gifu,Yamaguchi,Usuda) Ultra-rapid UT1 measurement (Onsala,Tsukuba,Metsahovi) 6Gbps S/X observation on Kashima-Koganei(100km) baseline. E-VLBI demonstration (ATNF-Kshima-Seashan) for today Hardware development Two types of K5 system(K5/VSSP, K5/VSI) ADS-3000plus(DBBC) development Benefit of Standard

  3. JGN2Sympo2007 with Haystack Mark5B

  4. Ultra-rapid UT1 Experiment E-VLBI Projct(1) Tsukuba32m（GSI) Onsala20m (Sweden） Within 5 min after the session, UT1has derived! Abiline/ Internet2 TransPAC Kashima34m（NICT) APAN Metsahovi14m (Finland） Geant2 JGN2 NorduNET Collaborators: R.Haas(Onsala), J.Ritakari, J.Wagner(Metsahovi), S.Kurihara, K.Kokado(GSI)

  5. DAS, Transport, Processing Work shared collaboration Observation and data transport at European side. Observation and Correlation processing at Japense side. Mark5 Mark5 E-VLBI Projct(1) Ultra-rapid UT1 measurement 128/ 256/ 512Mbps K5/VSSP Mk5 Onsala20m (Sweden） Tsunami/UDP VSIB (Metsahovi) Software Converter (K5 package) K5/VSSP Metsahovi14m (Finland） K5 K5 Correlation processing by K5 software correlator on cluster of PCs

  6. Prediction(BulletinA),EOPc04, and e-VLBI E-VLBI Projct(1)

  7. Rapid Solution (Bulletin-A) and e-VLBI – EOPc04 E-VLBI Projct(1)

  8. Success of 8Gbps real-time VLBI E-VLBI Projct(2) Kashima 34m NICT,Kashima Koganei 11m Headquater NICT, Tokyo 1１０km JGN2 10G-Ethernet VSI-H x4 VSI-H x4 VOA200

  9. VSI-H, VSI-S, VSI-E VSI-H VSI-H VSI-S RTP/RTCP Mark5B VSI-E VSI-H E-VLBI VSI-H Correlator Sampler DIM DOM

  10. 6Gbps routine VLBI for V773tau Name:V773 Tau A d=148pc Binary stars M:1.5M 1.3M a=0.4AU P=51 days E-VLBI Projct(2) • Monitoring of Flux • S/X dual Freq. • It is expected flare up with binary orbiting period. • Variation of Spectrum index associated with orbiting period. Kashima 34m Koganei 11m JGN2 10G-Ethernet VOA200

  11. The first real-time e-APT E-VLBI Projct(3) Kashima 34m Telescope Seattle Los Angeles JGN2Plus Shanghai 25m Telescope CSTNET AARNet ATCA 22m Telescope Parks 64m Telescope Sydney Mopra 22m Telescope

  12. A brief History of VLBI development in NICT From K3-systemto K5-system K4 Correlator K5 Data Acquisition Terminal K5 System K4 Terminal K4 (KSP) System K3 Correlator (Center) K3 Recorder (Right) 2002~ PC based system Hard Disks Software Correlator e-VLBI with IP 1990~ Rotary Head Recorder Cassette Tapes Hardware Correlator e-VLBI with ATM(256M) K3 System 1983~ Longitudinal Recorder Open Reel Tapes Hardware Correlator

  13. K5-System （１）: K5/VSSP VSSP = Versatile Scientific Sampling Processor K5/VSSP K5/VSSP32

  14. K5 System（２）: K5/VSI ADS1000 ADS3000 ADS2000 ADS3000Plus

  15. ADS1000 (1024Msample/sec 1ch 1 or 2bits) K5/VSSP32 Unit (~32Msample/ch·sec, ~4ch, ~8bits) K5 System ADS3000 (2048Msample/sec 1ch 8bits + FPGA) VSI-H PC-VSI Board (~2048Mbps) VSI-H Correlator other DAS Internet VSI-H ADS2000 (64Msample/ch·sec, 16ch, 1 or 2bits) VSI-H Mark5B sampler (64Msample/ch·sec, 16ch, 1 or 2bits) PC : Data Acquisition Correlation

  16. K5/VSIDBBC ADサンプラー：ADS3000 4Gbps (2GHz, 2sps) 初フリンジ （2006年1月）

  17. ADS3000 plus under development • Dual Channel sampler • For S/X observation • DBBC Function • VSI-H Compliant Sampling Mode

  18. ADS3000 + PC-VSI Recorder 4096Mbpsrecording for １７ hours

  19. Summary • VSI-Hwas quite successful, and useful. • Mark5B-K5＠JGN2Symp2007 • Mark5-VSIB@Ultra-rapid UT1 • NICT-NAOJ Devices(ADS-X000,VOA100/200,Software Corr(VERA) • Sharing standard interface reduces the cost and brings freedom and benefit for VLBIers. • E-VLBI era is good chanceto make all VLBI system fully compatible/connectable. • Handling data via software/network is great advantage. • We may discuss about standard or framework for taking compatibility. • Defining Standard Data Transport protocol

  20. Thank you for attention!

  21. Accuracy and latency of UT1 As an example of requirement: 10usec of accuracy(100m at Mars) can enables use of ar dragging and greatly reduce fuel weight for the space prove. E-VLBI Projct(1)

  22. What will happen when global e-VLBI is operated routinely? • At present, No problem for one stream Europe-Japan with shared network. Because of no congestion. • What about multiple streams? • In case of congestion, data rate drastically decreases, especially in TCP/IP. • Even Tsunami(UDP) tries to send complete data set by re-transmission mechanism, and … finally fails.

  23. What is the Optimal transport protocol for real-time VLBI? • Features of Realtime VLBI are • Fixed Data Rate or slightly adjustable. • Relatively large error rate(<0.1) is acceptable, if padding and flagging is done. Only Header must be preserved. • “Optimal protocol for realtime e-VLBI” may looks like • Sending data in fixed rate regardless congestion • Just sending out by UDP (without re-transmission) • VLBI data may win the resource race, because it accept largest error rate than any other application. • This may be good for VLBI, but….

  24. Conflict between Network and VLBI • Network is assuming Faire users, who shares network bandwidth equally. ex).TCP reduces transmitting rate in congestion condition. Video stream may adjust the rate by changing the compression or resolution of image. Rate controlis expected. • But VLBI cannot change the rate in case of real-time VLBI. “Optimal protocol for VLBI” may defeat other data streams, but it may be criticized and kicked out from network. ⇒Not good for VLBI

  25. Possible Solutions are • Bandwidth on demand connection • Realized by GMPLS and started in operation in SINET3. • Using Disk/Memory buffer to enable rate control… but it will not guarantee the success of realtime VLBI. Switching to offline or best effort basis VLBI. ⇒This may work with software correlator. • Bandwidth on demand connection will become available in global network in future.

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