Satellite beam steering reference using terrestrial beam steering terminals
First Claim
1. In a satellite communication system comprising at least one satellite having an antenna that generates a moving beam pattern on the surface of the earth, the beam pattern being comprised of a plurality of sub-beams, a method for determining an attitude correction signal for the satellite comprising the steps of:
- providing at least one reference transmitter at a known location on the surface of the earth;
transmitting at least one signal from the at least reference transmitter into at least one of the sub-beams;
receiving the at least one signal with the satellite antenna and transponding the received at least one signal to a ground station;
receiving the transponded at least one signal with the ground station;
determining a gain of the received at least one signal;
comparing the determined gain to a gain expected to be received based on a predetermined knowledge of a spatial variation in gain of the satellite antenna; and
determining a difference between the determined gain and the expected gain to derive a correction signal indicative of an attitude error of the satellite.
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Accused Products
Abstract
A satellite communication system has at least one satellite (1) with an antenna that generates a moving beam pattern on the surface of the earth. The beam pattern (3) is comprised of a plurality of sub-beams (4). A method of this invention determines an attitude correction signal for the satellite by the steps of: (a) providing at least one reference transmitter (10) at a known location on the surface of the earth; (b) transmitting at least one signal from the at least reference transmitter into at least one of the sub-beams; (c) receiving the at least one signal with the satellite antenna and transponding the received at least one signal to a ground station (8). A next step of the method (d) receives the transponded at least one signal with the ground station; (e) determines a gain of the received at least one signal; (f) compares the determined gain to a gain expected to be received based on a predetermined knowledge of a spatial variation in gain of the satellite antenna; and (g) and determines a difference between the determined gain and the expected gain to derive a correction signal indicative of an attitude error of the satellite. The method further includes the steps of transmitting the correction signal to the satellite; and correcting the attitude of the satellite in accordance with the correction signal.
80 Citations
38 Claims
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1. In a satellite communication system comprising at least one satellite having an antenna that generates a moving beam pattern on the surface of the earth, the beam pattern being comprised of a plurality of sub-beams, a method for determining an attitude correction signal for the satellite comprising the steps of:
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providing at least one reference transmitter at a known location on the surface of the earth; transmitting at least one signal from the at least reference transmitter into at least one of the sub-beams; receiving the at least one signal with the satellite antenna and transponding the received at least one signal to a ground station; receiving the transponded at least one signal with the ground station; determining a gain of the received at least one signal; comparing the determined gain to a gain expected to be received based on a predetermined knowledge of a spatial variation in gain of the satellite antenna; and determining a difference between the determined gain and the expected gain to derive a correction signal indicative of an attitude error of the satellite. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. In a satellite communication system comprising at least one satellite having an antenna that generates a moving beam pattern on the surface of the earth, the beam pattern being comprised of a plurality of sub-beams, a satellite attitude correction system comprising:
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at least one reference transmitter at a known location on the surface of the earth; means for transmitting at least one signal from the at least reference transmitter into at least one of the sub-beams; means for receiving the at least one signal from the satellite antenna and for transponding the received at least one signal to a ground station; means for receiving the transponded at least one signal with the ground station; means for determining a gain of the received at least one signal and for comparing the determined gain to a gain expected to be received based on a predetermined knowledge of a spatial variation in gain of the satellite antenna; and means for determining a difference between the determined gain and the expected gain to derive a correction signal indicative of an attitude error of the satellite. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. In a satellite communication system comprising at least one satellite having a steerable antenna that generates a moving beam pattern on the surface of the earth, the beam pattern being comprised of a plurality of sub-beams, a method for determining an antenna pointing correction signal for the satellite comprising the steps of:
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providing at least one reference transmitter at a known location on the surface of the earth; transmitting at least one signal from the at least reference transmitter into at least one of the sub-beams; receiving the at least one signal with the satellite antenna and transponding the received at least one signal to a ground station; receiving the transponded at least one signal with the ground station; determining a gain of the received at least one signal; comparing the determined gain to a gain expected to be received based on a predetermined knowledge of a spatial variation in gain of the satellite antenna; and determining a difference between the determined gain and the expected gain to derive a correction signal indicative of a pointing error of the satellite antenna.
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24. In a satellite communication system comprising at least one satellite having an antenna that generates a moving beam pattern on the surface of the earth, the beam pattern being comprised of a plurality of sub-beams, a method for determining beam pattern correction signal for the satellite comprising the steps of:
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providing at least one reference transmitter at a known location on the surface of the earth; transmitting at least one signal from the at least reference transmitter into at least one of the sub-beams; receiving the at least one signal with the satellite antenna; comparing a gain of the received at least one signal to a gain expected to be received based on a predetermined knowledge of a spatial variation in gain of the satellite antenna; and determining a beam pattern correction signal in accordance with a difference between the actual gain and the expected gain. - View Dependent Claims (25, 26, 27, 28)
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29. In a satellite communication system comprising at least one satellite having an antenna that generates a moving beam pattern on the surface of the earth, the beam pattern being comprised of a plurality of sub-beams, a method for determining beam pattern correction signal for the satellite comprising the steps of:
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providing at least one reference transmitter at a known location on the surface of the earth; transmitting at least one signal from the at least reference transmitter into at least one of the sub-beams; receiving the at least one signal with the satellite antenna; comparing a gain of the received at least one signal to a gain expected to be received based on a predetermined knowledge of a spatial variation in gain of the satellite antenna; determining a beam pattern correction signal in accordance with a difference between the actual gain and the expected gain; and correcting the beam pattern in accordance with the correction signal and in accordance with information obtained from at least one attitude sensor means carried by said satellite. - View Dependent Claims (30, 31, 32)
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33. In a satellite communication system comprising at least one satellite having an antenna that generates a moving beam pattern on the surface of the earth, the beam pattern being comprised of a plurality of sub-beams, a method for determining beam pattern correction signal for the satellite comprising the steps of:
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providing at least one transmitter at a location on the surface of the earth; transmitting at least one signal from the at least transmitter into at least one of the sub-beams using a predetermined access technique; receiving the at least one signal with the satellite antenna; comparing a gain of the received at least one signal to a gain expected to be received based on a predetermined knowledge of a spatial variation in gain of the satellite antenna; and determining a beam pattern correction signal in accordance with a difference between the actual gain and the expected gain. - View Dependent Claims (34, 35, 36, 37, 38)
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Specification