Selected aspects of advanced receiver autonomous integrity monitoring application to kalman filter based navigation filter
First Claim
1. A navigation system, comprising:
- one or more inertial sensors that generate inertial measurements;
a receiver configured to receive a plurality of signals transmitted from a plurality of space-based satellites; and
a processor operatively coupled to the receiver and the inertial sensors, the processor configured to perform a method of integrity monitoring, wherein the integrity monitoring performed by the processor comprises;
determining a full position solution for the navigation system based on the plurality of signals;
determining one or more position sub-solutions for the navigation system based on the plurality of signals;
setting values for unmodeled pseudorange biases;
computing a transformation matrix of the unmodeled pseudorange biases for the full solution and all sub-solutions using a Kalman filter;
computing a bias effect of the unmodeled pseudorange biases on an error of a filtered state vector component for all sub-solutions; and
adding the bias effect of the unmodeled pseudorange biases on the error of the filtered state vector component to computed protection levels for both vertical and horizontal dimensions.
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Abstract
A method of advanced receiver autonomous integrity monitoring of a navigation system is discussed and two modifications facilitating its implementation in a hybrid navigation system are disclosed. In the first approach, relations describing the effect of unmodeled biases in pseudo-measurement on the Kalman filter state estimate are analytically derived and their incorporation into the integrity monitoring algorithm is described. The method comprises receiving a plurality of signals transmitted from space-based satellites, determining a position full-solution and sub-solutions, specifying a pseudorange bias, computing a transformation matrix for the full-solution and all sub-solutions using a Kalman filter, computing a bias effect on an error of filtered state vectors of all sub-solutions, and adding the effect to computed vertical and horizontal protection levels. In the second approach, a modification for computationally effective calculation of the protection levels of hybrid navigation systems based on both integrity and non-integrity assured pseudorange error descriptions is disclosed.
36 Citations
15 Claims
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1. A navigation system, comprising:
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one or more inertial sensors that generate inertial measurements; a receiver configured to receive a plurality of signals transmitted from a plurality of space-based satellites; and a processor operatively coupled to the receiver and the inertial sensors, the processor configured to perform a method of integrity monitoring, wherein the integrity monitoring performed by the processor comprises; determining a full position solution for the navigation system based on the plurality of signals; determining one or more position sub-solutions for the navigation system based on the plurality of signals; setting values for unmodeled pseudorange biases; computing a transformation matrix of the unmodeled pseudorange biases for the full solution and all sub-solutions using a Kalman filter; computing a bias effect of the unmodeled pseudorange biases on an error of a filtered state vector component for all sub-solutions; and adding the bias effect of the unmodeled pseudorange biases on the error of the filtered state vector component to computed protection levels for both vertical and horizontal dimensions. - View Dependent Claims (4, 5, 6, 7, 8, 9)
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2. A navigation system, comprising:
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one or more inertial sensors that generate inertial measurements; a receiver configured to receive a plurality of signals transmitted from a plurality of space-based satellites; and a processor operatively coupled to the receiver and the inertial sensors, the processor configured to perform a method of integrity monitoring, wherein the integrity monitoring performed by the processor comprises; determining a full position solution for the navigation system based on the plurality of signals; determining one or more position sub-solutions for the navigation system based on the plurality of signals; computing a variance of a vertical position for the full position solution with a Kalman filter based on an integrity assured error definition; computing a variance of a vertical position for the full position solution with the Kalman filter based on a non-integrity assured error definition; computing a variance of the vertical position for all position sub-solutions with one or more additional Kalman filters based on the integrity assured error definition; computing a multiplying coefficient; and computing an approximate variance of the vertical position for all position sub-solutions based on the non-integrity assured error definition and the multiplying coefficient. - View Dependent Claims (3, 10, 11, 12, 13, 14, 15)
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Specification