| 摘要 |
PROBLEM TO BE SOLVED: To propose a new method of reducing the amount of data in satellite orbit data provided to a position calculating device. SOLUTION: In a position calculating system 1, a server system 3 uses a satellite predictive ephemeris acquired from an external system 2 to generate a long-term predictive ephemeris, namely, an ephemeris effective over a long time. In this case, the server system 3 determines a compression method, based on a change in parameter values with time for each of a satellite orbit model type parameter, a timepiece error model type parameter, and a parameter indicating the reliability in a satellite orbit. Then, a compression parameter value is calculated, by reducing bit trains indicating parameter values of the respective parameters, according to the determined compression method, and is provided to a portable telephone 4 as a compression long-term predictive ephemeris, along with identification information of the method of compressing each parameter value. COPYRIGHT: (C)2010,JPO&INPIT
|
