| 摘要 |
PURPOSE:To display the accurate position of a vehicle by assuming artificially satellite when the arrival of a radio wave from one of three artificial satellites is stopped. CONSTITUTION:When there are three receivable satellites, a reception position computing element 22 calculates both data, i.e. tracks from signal lines 20a and 20b and pseudo distance and the reception position of the vehicle 10 is displayed 24. If one of the satellite is made unreceivable because of the presence of a shield, the position of the vehicle 10 at the position is regarded as a pseudo satellite and azimuth and distance data from a magnetic goniometer 14 and a distance meter 16 are inputted to a pseudo computing element 26. On the other hand, measured position data on the vehicle 10 at the time t1 is sent to the computing element 26 as position information on a pseudo satellite and the pseudo distance data on the pseudo satellite obtained by processing said azimuth and distance data is sent to the computing element 22. The computing element 22 computes the measured position of the vehicle 10 on the basis of received data from receivable satellites at the current time t2 from a receiver 18, i.e. pseudo distance and satellite position data, the pseudo distance of the pseudo satellite of the computing element 26, and the position of the pseudo satellite of the device 2, so that the measured position is displayed 24.
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