Giga-bit Geodesy e-VLBI Using the Super-Sinet Hiroshi Takaba (Gifu University, Japan)

N. Kawaguchi, Y. Kono, H. Suda (NAOJ) K. Takashima, M. Ishimoto, M. Machida (GSI) Y. Koyama, T. Kondo, M. Sekido (NICT) H. Takeuchi (ISAS) N. Nakai (Tsukuba Univ.) H. Sudou, K. Wakamatsu (Gifu Univ.) and Japanese e-VLBI network group Collaborators

1) Giga-bit Geodesy e-VLBI by using the Super-Sinet between GSI Tsukuba 32m and Gifu 11m (311km apart) 2) Recent progress of the Japanese Giga-bit e-VLBI Network

What is Super-Sinet? Super-Sinet is the 10Gbps class dedicated network operated by Ministry of Edu. & Sci. for 5 research regions, 1) High Energy Physics & Nuclear Fusion 2) Space Science & Astronomy 3) Bio-informatics 4) Distributed computing (GRID) 5) Nano-technology connects some National Institutes & Universities

Super-sinet Sinet

Last 1-mile to the Super-Sinet We have to prepare the access fibers to the node! A CATV company provided fibers from High Energy Laboratory to GSI 32m at Tsukuba (about 10 km) with reasonable cost Gifu Prefecture operates Information Super-Highway, we borrowed two dark fibers from Fusion Research Laboratory to Gifu University (about 100km) free, we obtain two 2.4Gbps links by the WDM technique.

WDM(Wavelength Division Multiplexer) transceiver modules at a Gifu Prefecture’s Information Super Highway link station. We only use two wavelengths, up to 8links (OC48 or GbE) extensions are possible

Properties of our Giga-bit Geodesy e-VLBI System Dedicated Network - 2.4Gbps (OC48) x 2 ATM links - By using up and down links, we realized 4Gbps, 8Gbps will be possible! Real-time correlation, no recording for the raw data - XF type hardware correlator with 256lags - Fringes are found within 5min. and stable for 24hs. Simultaneous observations with K5/Giga-bit system - To check repeatability, reliability and for debugging

Giga-bit Real-time e-VLBI instruments at Gifu University Optical Transceiver 2.4Gbps x2 links With GbE A/D Converter (ADS1000) 2 channels XF type Correlator For 3 Baselines 256lags Correlator Control Computer

Real time Correlator Optical Transceiver OC48(2.4Gbps)× ２ A/D converter 2Gbps×2ch Super-Sinet OC48(2.4Gbps) Super-Sinet OC48(2.4Gbps) Super-Sinet OC48(2.4Gbps) Fusion Research Lab. NAOJ （ Mitaka City ） High Energy Lab. Tsukuba Gifu Univ. 11m Telescope32m Telescope Gifu Prefecture’s Information Super Highway Tsukuba CATV Super- Sinet Super- Sinet Giga-bit Geodesy e-VLBI using the Super-Sinet Optical Transceiver OC48(2.4Gbps)× ２ A/D converter 2Gbps×2ch Real time Correlator S X SX SX 100km 10km 500km? 100km? WDM

Real Time e-VLBI S band Processes at Mitaka X band Processes at Gifu Display the fringe pictures every 1 seconds S X Gifu Correlator Mitaka Correlator

Results of the K4/K5 and e-VLBI coincide within 3mm ! Results of Geodesy VLBI with K4/K5 and e-VLBI

X Band 2ch extension （ JD0608: Aug ） X high MHz X low MHz Gifu Correlator Mitaka Correlator

Some Problems Jitter of the sampler about 20ps for about 100 seconds integration (Koyama-san said it should be within several ps) 1 sec. slip of the Correlator outputs It sometimes happens for ch1 and ch3 correlators Systematic drifts of the delay time compared with K4/K5 and Giga-bit e-VLBI systems ～ 1ns for 24hours experiment

Differences of the delay time for K4 and Giga-bit e-VLBI 1ns ｓ Obs. # Xband pico-seconds

Almost same as K4 - Giga-bit e-VLBI! K5 and Giga-bit e-VLBI Xband pico-seconds

No large drift ！ K4 and K5 Xband pico-seconds

X band S band

Why Drift exists? K4 and K5 uses band width synthesis technique Giga-bit e-VLBI uses all IF bands and no-band width synthesis  Some drifts which can be canceled by the band synthesis technique, i.e. cable length change by the temperature, are seen?

Next Plan, 22GHz e-VLBI Install 22GHz band receivers for both Gifu 11m (November 2006) Tsukuba 32m (Nov.2006? by Tsukuba Univ.) 8Gbps(4ch) e-VLBI Oct Move a 3stn correlator from Mitaka to Tsukuba Add 4 more ADS1000 samplers (or 2 more ADS3000?) Make 4ch down-converters Apply 32GHz sampler to 22GHz receivers to make narrow beam Water Vapor Radiometers (2008?)

Real time Correlator Optical Transceiver OC48(2.4Gbps)× ２ A/D converter 2Gbps×4ch Super-Sinet OC48(2.4Gbps) Super-Sinet OC48(2.4Gbps) Super-Sinet OC48(2.4Gbps) Fusion Research Lab. NAOJ （ Mitaka City ） High Energy Lab. Tsukuba Gifu Univ. 11m Telescope32m Telescope Super- Sinet Super- Sinet 8Gbps e-VLBI using the Super-Sinet Optical Transceiver OC48(2.4Gbps)× ２ A/D converter 2Gbps×4ch Real time Correlator Real time Correlator Real time Correlator

Recent Progress of the Japanese Giga-bit e-VLBI Network Connected two Stations Nobeyama 45m (Dec. 2005) 22GHz/43GHz Yamaguchi 32m (April 2006) 8GHz => 2/8/22/43GHz, km extension New FX correlator with 16K lags completed InP HBT sampler with 32GHz/3bit testing

NAO Nobeyama45m Gifu Univ.11m 4.8 Gbps by Super-Sinet 2.4 Gbps by NTT or JGN2 Future Plan HokkaidoUniv.11m NAO Yamaguchi32m NAO Mizusawa20m NAO Kagoshima20m Japanese Giga-bit e-VLBI Network GSI Tsukuba32m NICT Kashima34m ISAS Usuda64m NAO HQ(Mitaka)

First Fringes detected between Yamaguchi 32m and Tsukuba 32m 3C84 in 8-GHz band April 23, 2006 New FX type correlator with 16K lags expands fringe search windows from 256ns to 16μs ! -14 μs

InP HBT AD Converter ADC DMX RF Signal A 32-GHz signal was successfully digitized with 3 bits. Ask Kawaguchi-san for more details

Imaging trial with fiber connected stations (8GHz band) Three station image (U64-T32-G11) C66B Four station image (U64-T32-K34-G11) 2005 Five station image Coming soon! Aug. 2006

Future Plan Connect VERA telescopes ～ 2011 Apply 22GHz/43GHz ultra-wide band geodesy e-VLBI to determine telescope positions within 1mm 2Beam+High speed switching e-VLBI observations for phase referencing => 10μas astrometry & sub-millimeter geodesy Also, connect KVN, China & Australian telescopes to make Asia Pacific e-VLBI network!