Navigation processing for a satellite positioning system receiver
First Claim
1. A plurality of instructions that control a SATPS receiver and verifies the validity of a SATPS three satellite solution, the plurality of instructions comprising:
- a first set of instructions that when executed for separates the three SATPS satellites into a first pair and a second pair;
a second set of instructions that when executed constructs a primary solution and an alternate solution, wherein the primary solution and the alternate solution satisfy the measurement constraints;
a third set of instructions that when executed computes a Doppler difference estimate for the primary solution and a Doppler difference estimate for the alternate solutions;
a fourth set of instructions that when executed computes Doppler difference residuals for the first pair and the second pair of SATPS satellites; and
a fifth set of instructions that when executed compares the Doppler difference residuals for said primary and alternate solutions to determine a valid solution.
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Abstract
A method for navigation processing in a satellite positioning system receiver is disclosed. A method in accordance with the present invention comprises separating the three SATPS satellites into a first pair and a second pair, constructing a primary solution and an alternate solution, wherein the primary solution and the alternate solution satisfy the measurement constraints, computing a Doppler difference estimate for the primary solution and a Doppler difference estimate for the alternate solution, computing Doppler difference residuals for the first pair and the second pair of SATPS satellites, and comparing the Doppler difference residuals for said primary and alternate solutions to determine a valid solution. Typically, the computing of a Doppler difference residuals comprises differencing a measured Doppler difference from an estimated Doppler difference for the first pair and the second pair of SATPS satellites. Typical determination of a valid solution comprises comparing the difference between the Doppler difference residuals to a predetermined number. Usually when the Doppler difference residuals exceed the predetermined number, the alternate solution is selected as the valid solution.
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Citations
20 Claims
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1. A plurality of instructions that control a SATPS receiver and verifies the validity of a SATPS three satellite solution, the plurality of instructions comprising:
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a first set of instructions that when executed for separates the three SATPS satellites into a first pair and a second pair;
a second set of instructions that when executed constructs a primary solution and an alternate solution, wherein the primary solution and the alternate solution satisfy the measurement constraints;
a third set of instructions that when executed computes a Doppler difference estimate for the primary solution and a Doppler difference estimate for the alternate solutions;
a fourth set of instructions that when executed computes Doppler difference residuals for the first pair and the second pair of SATPS satellites; and
a fifth set of instructions that when executed compares the Doppler difference residuals for said primary and alternate solutions to determine a valid solution. - View Dependent Claims (2, 3, 4)
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5. A method of verifying the validity of a SATPS three satellite solution, comprising:
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separating the three SATPS satellites into a first pair and a second pair;
constructing a primary solution and an alternate solution, wherein the primary solution and the alternate solution satisfy measurement constraints;
computing a Doppler difference estimate for the primary solution and a Doppler difference estimate for the alternate solutions and Doppler difference residuals for the first pair and the second pair of SATPS satellites;
comparing the Doppler difference residuals for said primary and alternate solutions to determine a valid solution; and
verifying the valid solution by selecting a first measurement validity test if a navigation state is known and a second measurement validity test if the navigation state is unknown. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A SATPS receiver, comprising:
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a receiver that is capable of receiving and demodulating at least three radio wave signals from respective SATPS satellites;
a controller that separates three of the at least three demodulated signals into a first pair and a second pair and calculates a primary solution along with an alternate solution from the first pair and the second pair, wherein the primary solution and the alternate solution satisfy measurement constraints; and
a Doppler difference estimator that estimates a Doppler difference for the primary solution and another Doppler difference estimate for the alternate solutions that are then used by the control to compute Doppler difference residuals for the first pair and the second pair of SATPS satellite signals where the Doppler difference residuals for the primary solution and the alternate solutions are used to determine a valid solution. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification