人工衛星レーザー測距観測による測地学,衛星軌道決定への貢献及び我が国測地系への世界測地系の導入

抄録

The Satellite Laser Ranging (SLR) observation by Japan Coast Guard (JCG) has been continued since 1982 at the Simosato Hydrographic Observatory in use of a fixed-type SLR system. Simosato is the base station of the Marine Geodetic Control Network connecting the mainland and isolated islands of Japan to a world geodetic system in order to delineate the limits of Japanese jurisdictional area at sea defined in the United Nation Convention of the Law of the Sea. Observation performance at Simosato has been improved, i.e., the single-shot precision of SLR observation has been improved: from 9.5 cm for LAGEOS-1 yearly RMS in 1986 to 1.5 cm in 2005, the total number of passes obtained at Simosato has increased from, e.g., 541 passes of 4 satellites in 1986 to 2, 331 passes of 24 satellites in 2005. The SLR data acquisition at Simosato for twenty-four years has been significantly contributing to establishing the International Terrestrial Reference Frame as well as to various research fields in global geodesy. A transportable SLR station, also developed by JCG, has been used to determine the positions of nine major isolated islands and other six sites at the edge of the mainland of Japan by observing geodetic satellites such as AJISAI launched in August 1986 by Japan. The processing of SLR data have been carried out using orbital processors developed by JCG and NASA. Geocentric coordinates and velocities of the SLR stations as well as geodynamical and earth-rotation parameters have been estimated by using SLR data. SLR observation and data processing by JCG have contributed to the establishment of the world geodetic system in 2002 as the national geodetic coordinate system of Japan .