| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To propose a new method of generating long-term prediction ephemeris. <P>SOLUTION: In a positioning system 1, a server system 3 variably sets the length of a period to be predicted for dividing a prescribed effective period of a satellite orbit so that the length becomes larger toward the future. More specifically, the larger a prediction error expressed by the difference between the actual position of a GPS satellite SV corresponding to a past prediction position included in satellite precise ephemeris obtained from an external system 2 and that included in a satellite prediction ephemeris obtained from the external system 2 is, the larger the length of the period to be predicted is set. Then, for each of a plurality of set periods to be predicted, a prediction orbit of a GPS satellite SV following a Kepler's elliptical orbit model is obtained based on the satellite prediction ephemeris to calculate the value of a satellite orbit parameter. Then, long-term prediction ephemeris data, where the calculated values of the satellite orbit parameters are collected for each period to be predicted, are generated and are provided to a cellular phone 4. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
