Synchronization method for a processing communication satellite

Abstract

The present invention provides a highly accurate synchronization method for a satellite communication system (). The system maintains a downlink symbol counter at an earth terminal and determines a downlink symbol count representative of the time of arrival of a burst transmitted from the earth terminal to a satellite (). The earth terminal adjusts the downlink symbol counter to correspond to the downlink symbol count () upon arrival of a predetermined reference point in a downlink frame. A timing error may initially be determined by launching an entry order wire from the earth terminal to the satellite (). The timing error may be transmitted to the earth terminal using a correction code which indicates the transmission is early, late, absent, or no change is required (). The terminal may make additional periodic timing adjustments based on the length of the propagation path between the earth terminal and the satellite (). The earth terminal may then precisely time the transmission of bursts from the earth terminal to the satellite (). The length of the propagation path and the timing error may be stored in the earth terminal so that the earth terminal may reenter the system without undertaking multiple commissioning processes.