Global system positioning receiver
First Claim
1. A Global Positioning System receiver comprising:
- receiving means for performing sampling of a received PN-code modulated carrier to generate in-phase (I) and quadrature-phase (Q) samples;
signal processor means coupled to outputs of said receiving means for removing a doppler frequency and PN-code modulation from said modulated carrier, said signal processor means comprises a plurality of channels, each of said channels including a correlator means, having sign and magnitude input weighting means, for correlating said I and Q samples with an in-phase (IREF) and a quadrature-phase (QREF) components of an internally generated PN-code reference, said correlator means controlled in response to a weighting select signal; and
means coupled to said signal processor means for processing said correlated I and Q samples.
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Abstract
An apparatus and method for pseudo-random noise (PN) code correlation in a GPS receiver employing sign and magnitude input weighting for each of the in-phase (I) and quadrature-phase (Q) samples of a received PN-code modulated carrier. A programmable R factor provides input A/D sample sign and magnitude weighting control of outside crossing samples for interference rejection of other RF signals interfering with the received PN-code modulated RF carrier. The R factor weighting determines if the A/D samples are from a linear or adaptive A/D converter. In-phase reference (IREF) signals and quadrature-phase reference (QREF) signals, produced by an internally generated PN-code reference, are provided to a plurality of I and Q multi-Y-tap correlator/integrators for correlation with the I and Q samples. The apparatus correlates I and Q samples obtained from IF sampling or baseband sampling of the received PN-code modulated carrier.
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Citations
46 Claims
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1. A Global Positioning System receiver comprising:
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receiving means for performing sampling of a received PN-code modulated carrier to generate in-phase (I) and quadrature-phase (Q) samples; signal processor means coupled to outputs of said receiving means for removing a doppler frequency and PN-code modulation from said modulated carrier, said signal processor means comprises a plurality of channels, each of said channels including a correlator means, having sign and magnitude input weighting means, for correlating said I and Q samples with an in-phase (IREF) and a quadrature-phase (QREF) components of an internally generated PN-code reference, said correlator means controlled in response to a weighting select signal; and means coupled to said signal processor means for processing said correlated I and Q samples. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A Global Positioning System receiver comprising:
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receiving means for performing sampling of a received PN-code modulated carrier to generate in-phase (I) and quadrature-phase (Q) samples; signal processor means, coupled to outputs of said receiving means, having a plurality of channels, each of said channels comprising; (a) means for removing received carrier doppler from said in-phase (I) and quadrature-phase (Q) samples; (b) means for generating a PN-code reference which is a replica of said received PN-code, said PN-code reference having an in-phase (IREF) component and a quadrature-phase (QREF) component; (c) means, coupled to said carrier doppler removing means and said PN-code reference generating means, for correlating said I and Q samples with said IREF and QREF components respectively of said replicated PN-code; (d) said correlating means comprises sign and magnitude input weighting of said I and Q samples including an I input weighting means coupled to a plurality of means for removing said PN-code modulated on said in-phase (I) component of said received carrier, and a Q input weighting means coupled to a plurality of means for removing said PN-code modulated on said quadrature-phase (O) component of said received carrier, each of said input weighting means being controlled in accordance with a weighting select input; and means coupled to said signal processor means for processing said correlated I and Q samples to determine the phase of said carrier signals, to provide multi-channel control signals to said signal processor means and to estimate a pseudo-range and pseudo-range rate. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A correlation apparatus comprising:
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means for removing received carrier doppler from in-phase (I) and quadrature-phase (Q) samples of a received pseudo-random noise (PN) code modulated carrier signal; means coupled to said received carrier doppler removing means for generating a PN-code reference which is a replica of said received PN-code, said PN-code reference having an in-phase (IREF) component and a quadrature-phase (QREF) component; and means, coupled to said carrier doppler removing means and said PN-code reference replica generating means, for correlating said I and Q samples with said IREF and QREF components respectively of said replicated PN-code. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for performing PN-code correlation in a Global Positioning System receiver comprising the steps of:
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sampling a received PN-code modulated carrier in a receiver means to generate in-phase (I) and quadrature-phase (Q) samples; removing a doppler frequency and PN-code modulation from said modulated carrier in a signal processor means, said signal processor means comprises a plurality of channels, each of said channels including a correlator means having sign and magnitude input weighting means; correlating in said correlator means said weighted I and Q samples with in-phase (IREF) and quadrature-phase (QREF) components of an internally generated PN-code reference; and processing said correlated I and Q samples in a processor means. - View Dependent Claims (30, 31, 32)
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33. A method of performing correlation comprising the steps of:
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removing received carrier doppler from in-phase (I) and quadrature-phase (Q) samples of a received pseudo-random noise (PN) code modulated carrier signal; generating a PN-code reference which is a replica of said received PN-code, said PN-code reference having an in-phase (IREF) component and a quadrature-phase (QREF) component; and correlating said I and Q samples with said IREF and QREF components respectively of said replicated PN-code. - View Dependent Claims (34, 35, 36)
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37. A radio receiver comprising:
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receiving means for performing sampling of a received PN-code modulated carrier to generate in-phase (I) and quadrature-phase (Q) samples; and signal processor means coupled to outputs of said receiving means for removing a doppler frequency and PN-code modulation from said modulated carrier, said signal processor means comprises a plurality of channels, each of said channels including a correlator means, having sign and magnitude input weighting means, for correlating said I and Q samples with an in-phase (IREF) and a quadrature-phase (QREF) components of an internally generated PN-code reference, said correlator means controlled in response to a weighting select signal. - View Dependent Claims (38, 39, 40, 41, 42)
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43. A method for performing PN-code correlation in a radio receiver comprising the steps of:
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sampling a received PN-code modulated carrier in a receiver means to generate in-phase (I) and quadrature-phase (Q) samples; removing a doppler frequency and PN-code modulation from said modulated carrier in a signal processor means, said signal processor means comprises a plurality of channels, each of said channels including a correlator means having sign and magnitude input weighting means; and correlating in said correlator means said weighted I and Q samples with in-phase (IREF) and quadrature-phase (QREF) components of an internally generated PN-code reference. - View Dependent Claims (44, 45, 46)
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Specification