Patent ID: 6694137
Filing Date: 2004-02-17
Classification: H01Q,H04B

Abstract:
A satellite-based communications network, comprisinga plurality of mobile user terminals with integrated tracking antennas; a communications satellite comprising at least a pair of transponders having overlapping frequency ranges and operative to transmit a downlink signal having certain polarization components and comprising video and audio content for reception by the mobile user terminals operating within a coverage area of the communications satellite; a plurality of remote monitoring terminals positioned at locations within the coverage area of the communications satellite, each monitoring terminal operative to monitor the polarization components of the downlink signal as received by the monitoring terminal and to output measured polarization data in response to monitoring of the downlink signal; and an uplink transmitting facility for transmitting an uplink signal for reception by the transponders of the communications satellite, the uplink transmitting facility responsive to the measured polarization data output by the monitoring terminals to control the relative phase and amplitude of the uplink signal, whereby the transponders are responsive to the relative phase and amplitude of the uplink signal to maintain at least a predetermined threshold of quality in the polarization components for the downlink signal received by the mobile user terminals operating in at least a portion of the coverage area for the communications satellite.