SS-TDMA technique telecommunication satellite systems

Claim 1

A satellite-switched time-division multiple access communication system, comprising: a satellite having a generally geostationary orbit; a plurality of ground communication stations having respective ground communication antennae trained upon said satellite; a plurality of ground beacon stations separate from one another and independent from said ground communication stations and having respective ground beacon antennae trained upon said satellite; on-board antenna means including at least one on-board satellite fine-tracking antenna on said satellite for receiving signals from said ground antennae and transmitting signals at least to said communication antennae; a reconfigurable on-board processor on said satellite for processing and switching information received from at least one of said communication antennae and retransmitting said information to at least another one of said communication antenna; demodulation/regeneration means connected to said antenna means for transmitting communication signals to said processor; remodulation means connected to said processor for delivering retransmitted communication signals representing the retransmitted information to said antenna means, said digital demodulation/regeneration means, said processor and said remodulation means forming a satellite switching system for time division multiple access communication between said communication stations; a beacon carrier generator at each of said ground beacon stations for generating a respective radio-frequency beacon carrier signal (f o ) for fine-tracking control of said on-board fine-tracking antenna; modulator means at each of said ground beacon stations for modulation of a subcarrier (CM o ) forming a reference clock signal with a high-speed telecommand signal (HSCMD) for controlling said on-board processor and for modulating, in turn, said beacon carrier signal (f o ) with the subcarrier (CM o ) as modulated by the high-speed telecommand signal (HSCMD) to form a transmitted modulated signal transmitted by the respective ground beacon antenna to the on-board antenna system; respective on-board demodulators forming part of a radio-frequency receiver receiving the transmitted modulated signals transmitted by the respective ground beacon antennas and demodulating same to recover an antenna-control signal (ERR) for fine control of said on-board in response to said carrier (f 0 ), a clock signal (CM) at a communication symbol frequency as determined by the frequency of said subcarrier (CM o ), and the telecommand signal (HSCMD); on-board selecting means on the satellite connected to said on-board demodulators for selecting among the demodulated signals for utilization of the qualitatively better of the signals selected between; decoder means connected to said on-board selecting means and responsive to said telecommand signal (HSCMD) for controlling said processor to effect time division multiple access communication switching between said communication stations; and synchronizing means connected to said on-board selecting means and responsive to said clock signal (CM) for synchronizing said digital demodulation/regeneration means, said processor and said remodulation means.