| 摘要 |
Whether or not a pseudo GPS signal is normally received is monitored from the data state in a reception unit. Then, at the stage when the pseudo GPS signal can be normally received, the satellite output timing is substantially synchronized with the ground reference time while the control is carried out so as to advance/delay the timing of outputting a transmission PN code in correspondence to the moving direction of a satellite. Subsequently, a time period ranging from a time point when transmitting the pseudo GPS signal to a time period when receiving the pseudo GPS signal which has been returned via the satellite is observed, while the control is carried out so as to increase/decrease continuously a frequency of the transmission PN code, in such a way that the intermediate time therebetween becomes the reference time. Next, the frequency of the transmission carrier is controlled in correspondence to the control of increasing/decreasing the frequency of the transmission PN code, while the epoch pull out and the reception interruption are monitored, so as to maintain the relationship in which the frequency of the received carrier is 1,540 times as high as that of the received reception PN code frequency. By executing the above-mentioned processings, it is possible to cancel the transponder frequency error of the geostationary satellite site as well as the Doppler component added in the uplink.
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