| 摘要 |
PROBLEM TO BE SOLVED: To provide a positioning method using a GPS, in which the TTFF (Time To First Fix) can be made as rapid as possible, when a positioning device using the GPS is started up after the elapsed time of Ephemeris information exceeds its lifetime. SOLUTION: Each orbital information of a plurality of GPS satellites stored in a storage section is monitored as to whether the elapsed time exceeds respective lifetime established beforehand. As a result of monitoring, in the case orbital information exceeding the lifetime is detected from the orbital information of the plurality of GPS satellites, the orbital information is updated, when the acquisition of new orbital information is completed about the orbital information exceeding the lifetime. The calculation of positioning is determined as to whether the orbital information exceeding the lifetime is used. A positioning result calculated to which an index representing reliability of positioning accuracy is added, is output on the basis of the determined result. COPYRIGHT: (C)2003,JPO
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