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-sinetSinet

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 linksWith GbE

A/D Converter(ADS1000)2 channels

XF type CorrelatorFor 3 Baselines

256lags

Correlator Control Computer

Real timeCorrelator

Optical TransceiverOC48(2.4Gbps)×２

A/D converter2Gbps×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 Telescope 32m Telescope

Gifu Prefecture’sInformation Super Highway

TsukubaCATV

Super- Sinet

Super- Sinet

Giga-bit Geodesy 　 e-VLBI using the Super-Sinet

Optical TransceiverOC48(2.4Gbps)×２

A/D converter2Gbps×2ch

Real timeCorrelator

S

X

S XS X

100km

10km

500km? 100km?

WDM 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. 2006）　

X high8180-8680MHz

X low7780-8280MHz

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

K4-sinet J D0404)（

-1000

-500

0

500

1000

0 20 40 60 80 100 120 140

遅延

時間

の差

（ｐ

ｓ）

1ns ｓ

Obs. #

Xband

pico-seconds

K5-sinet J D0404)（

-1000

-500

0

500

1000

0 20 40 60 80 100 120 140

遅延

時間

の差

（ｐ

ｓ）

Almost same as K4 - Giga-bit e-VLBI!

K5 and Giga-bit e-VLBI

Xband

pico-seconds

K4-K5 (J D0404)

-1000

-500

0

500

1000

0 20 40 60 80 100 120 140

遅延

時間

の差

（ｐ

ｓ）

No large drift！

K4 and K5

Xband

pico-seconds

K5-SINET (J D0509)

-1000

-500

0

500

1000

0 50 100 150 200

OBS. NUMBER

delt

a d

ela

y (

ps)

X　band

K5-SINET Sband (J D0509)

-1000

-500

0

500

1000

0 50 100 150 200

OBS. NUMBER

delt

a d

ela

y(p

s)

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. 2007 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 bea

m Water Vapor Radiometers (2008?)

Real timeCorrelator

Optical TransceiverOC48(2.4Gbps)×２

A/D converter2Gbps×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 Telescope 32m Telescope

Super- Sinet

Super- Sinet

8Gbps e-VLBI using the Super-Sinet

Optical TransceiverOC48(2.4Gbps)×２

A/D converter2Gbps×4ch

Real timeCorrelator

Real timeCorrelator

Real timeCorrelator

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, 55-800km 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-Sinet2.4 Gbps by NTT or JGN2Future 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

DMX

RFSignal

A 32-GHz signal was successfully digitized with 3 bits.

Ask Kawaguchi-san for more details

Imaging trial with fiber connected stations (8GHz band)

1928+738

Three station image(U64-T32-G11) 2004

3C66B

Four station image(U64-T32-K34-G11) 2005

Five station imageComing 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!