| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and device that roughly calculate a transmission time advance offset in a way that transmission data are received in a proper window without loss. SOLUTION: A subscriber equipment 30 is operated in a synchronization communication system having dynamic nodes such as satellites 12, 12'. The satellites 12, 12' adopt a string transmission and reception time window and all transmission data addressed to the satellites 12, 12' are required to enter the reception window when the data are to be recognized. In the dynamic communication system where the low earth orbit satellites 12, 12' are circulated on respective orbits continuously, a propagation timing between the satellite 12 and the subscriber equipment 30 is fluctuated at a high speed over a wide timing range. the subscriber equipment 30 should roughly calculate a transmission advance timing used to start its transmission to the satellite 12. subscriber equipment 30 utilizes a valid geographical position when available but when the position is not available or not valid, the equipment 30 generates the initial rough calculation value for propagation delay depending on the configuration characteristic of conformation. |
