| 摘要 |
The invention concerns a method and a device for determining transit time DELTA T of signals between a ground station equipped with a ground system (3), and a space craft equipped with an airborne system (14). The method consists in generating in the ground system (3) and transmitting to the space craft a synchronisation frame TC-Dist, comprising at least a synchronisation bit; measuring and recording in the ground station the ground- DELTA tground time interval between the transmission time of the synchronisation bit and the reception time of a reference bit of a telemetering frame whereof the number NTs is recorded; generating and transmitting to the space craft a measuring frame TC-mes, incorporating DELTA tground and NTs; measuring on board the space craft the time interval airborne-airborne DELTA t time interval between the reception of a synchronisation bit and the transmission of the reference bit of a telemetering frame whereof the frame number NTb is recorded; calculating the transit time DELTA T with the formula: 2 DELTA T = DELTA - DELTA tground + (NTb NTs) x d frame (ground) bias - (airborne) bias - (ground) noise - (airborne) noise.
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