| Co-Investigator(Kenkyū-buntansha) |
SHIBUYA Kazuo National Institute of Polar Research,Associate Professor, 研究系, 助教授(昭和60年度 (80132710)
ITO Kiyoshi Regional observation Center for Earthquake Prediction,Faculty of Science,Kyoto U, 理学部地震予知観測センター, 助手 (80022721)
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| Research Abstract |
In order to examine the geoidal undulation in the mountaneous region,determination of precise geocetric coordinates of the triangulation stations on the local geodetic datum is made using a two-wave NNSS receiver. The comparison of the obtained height above the Standard Illipsoid with the elevation above mean sea level will give us precise geoid height at the receiving station.
Convergent procedures of the receiving experiments by the broadcast ephemeris point positioning method, precise ephemeris point positioning method and broadcast ephemeris translocation method are examined in detail using the satellite passes obtained simultaneously at Tsukuba,Dodaira and the reference station at the National Institute of polar Research (Shibuya,1985;Shibuya and Kitazawa,1986). The translocation reference station is identical with the geodetic control station installed at the National Institute of polar Research (Itabashi,et al.,1986),and translocation of 10 triangulation statios in the central pa
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rt of Japan is made. Selected stations are; (1) Takidera,Yane and Tomariyama from the Hapanese Sea coastal region of the Chubu District, (2) Mt.Fuji, Mt.Norikura and Mt.Tateyama from the mountain region,and (3) Tsukuba,Dodaira,Izu-oshima Island and Fuji City in the Kanto-Tokai District.
When more than 10 satellite passes with good geometry are analyzed,satellite Doppler positioning in the geocentric coordinate system can be made with the convergence error better than 0.5-1.0m for latitudinal, longitudianl and height derections,respectivesy (Kaminuma,et al.,1988). Absolute positioning error of the translocation reference point inherent in the translocation technique can be neglected in the discussion of relative geoid height in the region conceined. The obtained geoid heights are for example 41.3m (NIPR reference point),41.0m (Mt.Fuji) and 45.8m (Tsukuba) on the WGS72 Ellipsoid. The obtained distribution of geoid heights at the selected 10 stations are in good agreement with the gravimetrically derived geoid around Japan by Ganedo (1982),and the probable short-wavelength geoidal undulation is estimated to be within 2m at most (Shibuya,et al.,1988). Less
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