| 摘要 |
PROBLEM TO BE SOLVED: To provide an apparatus for measuring a speed of a mobile station capable of reducing the period when the speed cannot be measured by a GPS and can measure the travel speed of the mobile station even if cycle slip occurs. SOLUTION: A first speed measuring means 23 fuses the Doppler speed determined based on Doppler frequency Da from a positioning means 22 and an integral speed obtained by integrating acceleration at the optimal mixture ratio according to the difference between them, and measures travel speed V1 of the mobile station. A second speed measuring means 25 measures travel speed V2 of the mobile station by a TD (Time Differential) method based on the position Db of the mobile station from the positioning means 22. A switch control means 24 performs switch control so that travel speed V1 is measured by the first speed measuring means 23 after the occurrence of the cycle slip and in the initial stage of restoration from the cycle slip, and travel speed V2 is measured by the second speed measuring means 25 when cycle slip does not occur. This control reduces the cleanup period of the speed measurement. COPYRIGHT: (C)2008,JPO&INPIT
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