Navigation system with solution separation apparatus for detecting accuracy failures
First Claim
1. A navigation system for a vehicle, comprising:
- receiving means for mounting to the vehicle and for receiving a plurality of signals from a plurality of transmitters;
solution means for determining a position solution for the vehicle, based on the plurality of signals;
subsolution means for determining a plurality of position subsolutions for the vehicle, with each subsolution based on a respective subset of the plurality of signals;
solution separation means for determining a plurality of solution separation parameters, with each solution separation parameter based on statistics of a separation between the position solution and a respective subsolution; and
error bound means for determining an error bound for the position solution, based on at least one of the solution separation parameters.
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Accused Products
Abstract
A navigation system, incorporating a unique method for detecting failures and determining an accuracy or error bound, has a receiver for receiving signals from several remote transmitters and a processor for determining a position solution from the signals. The processor, preferably employing Kalman filtering techniques, also determines several position subsolutions from subsets of the signals. The processor then computes covariance-based solution separation parameters based on statistical worst-case differences, or separations, between the position solution and the subsolutions. Similarly, the processor also computes error parameters defining statistical worst-case errors in each position subsolution. With the solution separation and the subsolution error parameters, the processor determines an error bound for the position solution. The processor also uses the separation parameters as detection thresholds for detecting transmitter failures. In one embodiment, the processor incorporates inertial reference data into the solutions and ultimately into the error bound calculation, thereby improving the ability of the navigation system to monitor its own accuracy, or integrity.
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Citations
43 Claims
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1. A navigation system for a vehicle, comprising:
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receiving means for mounting to the vehicle and for receiving a plurality of signals from a plurality of transmitters; solution means for determining a position solution for the vehicle, based on the plurality of signals; subsolution means for determining a plurality of position subsolutions for the vehicle, with each subsolution based on a respective subset of the plurality of signals; solution separation means for determining a plurality of solution separation parameters, with each solution separation parameter based on statistics of a separation between the position solution and a respective subsolution; and error bound means for determining an error bound for the position solution, based on at least one of the solution separation parameters. - View Dependent Claims (2, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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- 3. The system of claim I wherein the solution separation means determines each solution separation parameter from a respective covariance matrix describing the statistics of the separation between the position solution and the respective position subsolution.
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23. A position measurement system for a vehicle, comprising:
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receiving means for mounting to the vehicle and for receiving a plurality of signals from a plurality of transmitters; solution means for determining a position solution for the vehicle, based on the plurality of signals; subsolution means for determining a plurality of position subsolutions for the vehicle, with each subsolution based on a respective subset of the plurality of signals; solution separation means for determining a plurality of solution separation parameters, with each solution separation parameter based on statistics of a separation between the position solution and a respective subsolution; and detection means for detecting a transmitter failure based on at least one of the solution separation parameters. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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31. A method of operating and monitoring a position measurement system for a vehicle, the method comprising:
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determining a position solution for the vehicle, based on a plurality of signals from a plurality of transmitters; determining a position subsolution for the vehicle, based on a subset of the plurality of signals; determining a solution separation parameter from statistics of a separation between the position solution and the position subsolution; determining a discriminator based on the position solution and the position subsolution; detecting a transmitter failure based on the relationship of the discriminator and the solution separation parameter. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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Specification