| 摘要 |
PURPOSE:To perform invariably accurate position measurement calculation by investigating the rate of variation in the arrival time of an epoch signal from each satellite which is necessary for pseudo range calculation and interrupting normal pseudo range arithmetic when it exceeds a prescribed value. CONSTITUTION:Global positioning system (GPS) satellite signals which are received by an antenna 10 from four satellites are converted 11 in terms of frequency and inputted to synchronous demodulating circuits 12-15 of channels 1-4. The circuits 12-15 input PN codes which are generated 16 to PN code circuits 17 and use outputs of BPSK demodulating circuits 18 as feedback signals; and the phases of the PN codes which are generated 17 are controlled and inputted to modulators 20, so that the outputs of voltage-controlled oscillator 19 are modulated 20. The outputs of the modulators 20 are supplied to a microcomputer (MC) 24 through modulators 21, band-pass filters 21, and circuits 18. A pseudo range measuring circuit 23, on the other hand, measures artificial distance from the propagation delay time of a signal from a satellite and supplies the result to the MC 24. The MC 24 performs position measurement arithmetic and the result is displayed 26.
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