Patent ID: 6128468
Filing Date: 2000-10-03
Classification: G01S,H04B

Abstract:
A satellite telecommunications system comprising:a ground station to transmit signals to and receive signals from a least one earth orbiting satellite,a user terminal to transmit signals to and receive signals from the satellite, whereby to provide communication between the ground station and the user terminal via the satellite, the satellite providing user terminal transmissions in a plurality of radio beams which define adjacent cellular areas of coverage on the earth,a processor to process signals received by the user terminal according to at least one predetermined characteristic to determine data corresponding to first and second positional loci for the user terminal which intersect twice in a particular one of the cellular areas to define first and second possible positions for the user terminal both of said possible positions being within said particular one of the cellular areas, anda monitoring system to monitor the quality of signals received by the user terminal from the radio beams corresponding to the cellular areas of coverage adjacent to said particular one thereof and to determine from the measured qualities of the monitored signals, which of said possible positions for the user terminal corresponds to its actual position in said particular cellular area.