| 摘要 |
PROBLEM TO BE SOLVED: To reduce the amount of ephemeris data to be provided to a positioning device. SOLUTION: In a positioning system 1, a server system 3 calculates predicted orbits of a plurality of GPS satellites SV rotating a predetermined earth orbit using predicted positions of the GPS satellites SV stored in a satellite prediction almanac acquired from an external system 2. The system generates compressed long-term predicted ephemeris by calculating difference values between parameter values of reference orbits which are average orbits of satellites rotating the same orbits as those of the plurality of GPS satellites SV and the predicted orbits of the GPS satellites SV, and storing the difference values instead of the parameter values of the predicted orbits. The system sends the generated compressed long-term predicted ephemeris to a portable telephone 4 according to a request from the portable telephone 4. COPYRIGHT: (C)2010,JPO&INPIT
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