Events

JGN2 Symposium 2007 { conference webpage }

Real-time e-VLBI demo over the intercontinental baseline (9500km)

Jan 17-19, 2007
Hiroshima, Japan
http://www.ilcc.com/jgn2/e/index.html

• e-VLBI demonstration at JGN2 Symposium 2007
  

Local mirror of e-VLBI demonstration page (as of Thu Jan 25 2007):

Kashima 34m	Westford 18m

• VLBI Demonstration
  

  Stations:	Kashima 34m(NICT) , and Westford 18m (MIT)
  Radio Sources:	3C84, 3C454.3
  Data Acquisition:	Receiving data from Mark5B, and VSI1000 sampler via VSI-H interface at each sites Westford and Kashima.
  Observation Mode:	16MHz 2bit 16channel (512Mbps/Stn)
  Data transfer rate:	16MHz 2bit 1channel (32Mbps)

• Network - Shared 1G net and JGN2
  1G Shared network was used for data transfer from Westford to Japan. Data transfer protocol was TCP/IP. Stable data transfer rate of TCP/IP on the shared-net was 32Mbps, then 32Mbps 1 channel of data have extracted and transfered to Japan.
• Distributed Processing -GMPLS
  Optically linked PCs are used for the platform of real-time correlation processing with software correlator. The data processing PCs are located at distant places and connected by optical link organized by GMPLS.
• Software
  Software tools for data distribution and data stream extraction (channel decomposition) servers are newly developed for this demonstration.

  VSI2000 data sender	Sending data from VSI-interface card to the network
  Channel Decomposer Server	Extracting requested 2bit stream from 32bit parallel VSI-H
  Data Distributor Server	Distributing data to correlator clients

• Result
  We performed real-time e-VLBI demo over the intercontinental baseline (9500km). The observed data at each radio telescopes were transfered to Software correlator working at Tokyo. Due to limited stable link with TCP/IP, we taransfered single channel of data extracted from 32-bit VSI-H data stream in realtime. The frige was succsesfully detected with software correlator in real-time and displayed in a screen at Hiroshima, where JGN2 symposium was held.

  Fringe of 3C84 detected in this demo in real-time

Acknowledgements

The software tools for data transfer are developed by using class library of C++, which has originally written by David Lapsley. That library enabled quick development of these tools by us. We appreciate Chester Ruszczyk for strongly supporting this demonstration from Haystack Observatory. We thank to Michael Poirier, Allan Whitney, and people of MIT Haystack Observatory for operating the Westford radio telescope for this demonstration. The network for this e-VLBI demonstration has been supported by JGN2, Asia Pacific Advanced Network (APAN), Internet 2, and DRAGON project. We appreciate their contribution to this demonstration.

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Pictures and Poster of the Demonstration

JGN2 Symposium e-VLBI Posters