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GI1-1TH5P-0026 Data transmission and long separation relationship handling examinations for space geodesy through the satellite TCP/IP join in the South Pacific ICHIKAWA Ryuichi( richi@nict.go.jp ) (1) , TAKEUCHI Hiroshi (1) , Hasegawa Akio (2) , Osaki Hiroo, KONDO Tetsuro (1) , KUROIWA Hiroshi (2) , TAKAHASHI Fujinobu (3) , Eroni Vari (4) , Paserio Samisoni (4) , David A. PHILLIPS (5) , and Michael BEVIS (6) (1) Kashima Space Research Center, National Institute of Information and Communications Technology, JAPAN (2) ATR, JAPAN, (3) University of South Pacific, SUVA, FIJI, (4) Yokohama National University, JAPAN (5) Lands & Survey Dept., Suva, FIJI, (6) PGF/University of Hawaii, USA, (7) Ohio State University, USA ABSTRACT Full-time perceptions at universally disseminated VLBI stations are attractive for the ongoing checking of the earth introduction. Be that as it may, pacific and southern half of the globe scope is not adequate. On the off chance that we have the capacity to utilize a rapid TCP/IP information connection utilizing an optical fiber system or wideband satellite correspondence at the South Pacific Islands, the condition of-workmanship e-VLBI framework which we are creating will have the capacity to fill a hole in the VLBI perception system. Also, the plate\'s observing movements and ocean level changes utilizing GPS estimations as a part of the South Pacific backings investigations of common dangers and environmental change. Sadly, since there are no VLBI stations in the South Pacific Islands, the position directions of GPS stations are not fixing to the worldwide reference framework with adequate exactness. The neighborhood tie between the VLBI station and the nearby GPS system will enhance the accuracy. We began to add to the VLBI and GPS information exchange framework utilizing the satellite TCP/IP join. There is a satellite station in the University of South Pacific (USP), SUVA, Fiji. In spite of the fact that the band width of 1536Kbps is insufficient to transmit the colossal information sets, for example, Gigabit VLBI information, we can really assess the R&D results to send the space geodetic information from Fiji to Japan. Our investigations were effectively completed amid the times of February 9-14, 2004 and January 16-21, 2005. We introduced a GPS station, a pre-introduced Linux server including the test VLBI information, and a best in class satellite switch in the USP. In the year of 2004 trial we assessed the throughput rate utilizing the new satellite switch which can enhance the most extreme throughput of a TCP association with maintain a strategic distance from the time delay because of the round excursion time (RTT). The GPS and VLBI information sets in the USP server were transmitted by means of FTP from Fiji to Japan. The crest throughput was more than more or less 1440Kbps which is up to around 94% of the ostensible most extreme throughput. In the year of 2005 trial we attempted the K5 programming relationship of VLBI information sets utilizing the system disseminated preparing framework (we call this “ VLBI@home ”) in the middle of Japan and Fiji. The long-separate relationship handling through satellite connection was effectively performed. Furthermore, the parallel information transmission and asset sharing innovations was essentially valuable to diminish the RTT impact. Geodetic and geophysical importances in the South Pacific exact and constant checking of the Earth Orientation Parameters (EOP) utilizing e-VLBI method ocean level change plate tectonics neighborhood tie between the VLBI site and the nearby GPS system Forces that irritate Earth pivot [Lambeck, 1980] K5 VLBI System Plate movements recognized by the GPS estimations in Tonga-Lau Basin [Bevis et al., 1995] We require a fast TCP/IP information join in the South Pacific. Figure 1 Motivation of our study Communication satellite (Superbird C) Japan Fiji SUVA IGS site introduced by University of Hawaii, USA PC(Linux) TCP/IP join switch Serial (RS232C) connection Satellite Com. station PC(Win) Hawaii(UH) mobile phone join GPS station and satellite correspondence offices in USP HUB switch Satellite Com. station PC(Win) PC(Linux) PC(Win) GPS RX Figure 2 Schematic picture of the information transmission investigation Figure 4 Schematic picture of the TCP/IP join in our study Nadi Suva Gov. Building 100km Viti Levu(Big Island) ~2km USP Figure 3 Map of study field

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