| 摘要 |
PROBLEM TO BE SOLVED: To adequately evaluate the current position candidate of each satellite set depending on receiving environment. SOLUTION: When a difference (a positioning altitude difference) between a maximum value (a maximum altitude) and a minimum value (a minimum altitude) for the altitude of the current position candidate P of each satellite set exceeds a predetermined threshold valve (200 m, e.g.), receiving environment is determined as "multi-pass environment", and when it does not exceed, the receiving environment is determined as "open-sky environment". In the case that the receiving environment is the open-sky environment, an evaluation point E of each satellite set is calculated in a known evaluation method based on the number of satellites or PDOP values. In the case that it is multi-pass environment, the evaluation point E of each satellite set is calculated similarly to the case of the open-sky environment. Furthermore, the evaluation point E is reduced by a change amountΔE depending on a difference (an altitude difference) between an altitude corresponding to a previous positioning site acquired from an altitude table and the altitude of the current position candidate of the satellite set. COPYRIGHT: (C)2009,JPO&INPIT |
