Satellite communications terminal location system and method
First Claim
Patent Images
1. 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.
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Accused Products
Abstract
In a satellite communications system, where a satellite 10 provides a plurality of radio beams 30, and where distance and/or angle measurement from a satellite 10 or satellites 10 enables the position of the user terminal 44, on the surface of the earth 14, to be measured to within an uncertainty of being in one out of a possible plurality of positions 142, when some out of the plurality of positions fall within a single beam 30A, which one of the plurality of possible positions 142 is actually occupied by the user terminal 44 is determined by assessing the quality of signals received from those other, adjacent, overlapping beams 30B-30G which surround the beam 30A.
16 Citations
17 Claims
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1. A satellite telecommunications system comprising:
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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, and a 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of resolving positional ambiguities in a satellite telecommunications system wherein a ground station and a user terminal transmit signals to one another via a least one earth orbiting satellite, the satellite providing user terminal transmissions in a plurality of radio beams which define adjacent cellular areas of coverage on the earth, the method comprising
processing 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 in said cellular area, and monitoring 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.
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17. A user terminal for a satellite telecommunications system wherein a ground station transmits signals to and receives signals from a least one earth orbiting satellite, and the satellite provides user terminal transmissions in a plurality of radio beams which define adjacent cellular areas of coverage on the earth, the user terminal comprising:
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a transmitter-receiver unit 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, 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, and a 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 whereby to permit a determination to be made 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.
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Specification