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  • Letter
  • Open Access

Ultra-rapid UT1 measurement by e-VLBI

  • Mamoru Sekido19Email author,
  • Hiroshi Takiguchi19,
  • Yasuhiro Koyama19,
  • Tetsuro Kondo19,
  • Rüdiger Haas29,
  • Jan Wagner39,
  • Jouko Ritakari39,
  • Shinobu Kurihara49 and
  • Kensuke Kokado49
Earth, Planets and Space200860:BF03352838

Received: 31 October 2007

Accepted: 6 June 2008

Published: 8 September 2008


The latency of UT1 measurement with Very Long Baseline Interferometry (VLBI) has been greatly reduced by using e-VLBI technology. VLBI observations on the baseline formed by the Kashima 34-m and the Onsala 20-m radio telescopes achieved ultra-rapid UT1 measurements, where the UT1 result was obtained within 30 min after the end of the observing session. A high speed network and a UDP-based data transfer protocol ‘Tsunami’ assisted the high data rate and long-distance data transfer from Onsala to Kashima. The accuracy of the UT1 value obtained from the 1-h single baseline e-VLBI experiment has been confirmed to be as the same level with the rapid combined solution of Bulletin-A. The newly developed technology is going to be transferred to the regular intensive VLBI sessions, and it is expected to contribute to the improved latency and accuracy of UT1 data.

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