| 摘要 |
PURPOSE: To provide a GPS receiving device capable of detecting the abnormal state of a GPS satellite without the time delay until the health information of the satellite is received. CONSTITUTION: A satellite time/satellite frequency measurement section 32 measures the satellite time and Doppler frequencies, and a position measurement calculation section 38 calculates the user position data and GPS satellite position data from the orbit data collected through a navigation data demodulation section 30 and an orbit data collection section 34 and the satellite time and Doppler frequencies measured by the satellite time/satellite frequency measurement section 32. A real-time clock section 40 measures the time of a GPS receiving device 20, and a satellite time judgment section 42 compares the satellite time with the time measured by the real-time clock section 40. If the satellite time coincides with the time measured by the real-time clock section 40 or the difference lies within a prescribed range, the GPS satellite is referred to be normal for position measurement. If not, the GPS satellite signal is not employed. |
