Selected aspects of advanced receiver autonomous integrity monitoring application to kalman filter based navigation filter

Patent metadata

Field	Value
Publication number	US-9547086-B2
Application number	US-201313850341-A
Country	US
Kind code	B2
Filing date	Mar 26, 2013
Priority date	Mar 26, 2013
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

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.

First claim

What is claimed is:

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.

2. 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;
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.

3. The system of claim 2 , wherein the integrity monitoring performed by the processor further comprises:
computing a covariance matrix of the horizontal position for a full position solution with the Kalman filter based on the integrity assured error definition;
computing a covariance matrix of the horizontal position for the full position solution with the Kalman filter based on the non-integrity assured error definition;
computing a covariance matrix of the horizontal position for all position sub-solutions with the one or more additional Kalman filters based on the integrity assured error definition;
computing maximum eigenvalues for the horizontal position covariance matrices;
computing a multiplying coefficient; and
computing approximate maximum eigenvalues for the horizontal position covariance matrices for all position sub-solutions based on the non-integrity assured error definition and the multiplying coefficient.

4. The system of claim 1 , wherein the receiver is configured to receive signals from a global navigation satellite system (GNSS).

5. The system of claim 1 , wherein the receiver is configured to receive signals from a multi-constellation, multi-frequency GNSS.

6. The system of claim 1 , wherein the inertial sensors are implemented in an inertial measurement unit.

7. The system of claim 1 , further comprising one or more additional sensors in operative communication with the processor.

8. The system of claim 1 , wherein the system is onboard an aircraft.

9. The system of claim 1 , wherein the integrity monitoring is implemented as part of an advanced receiver autonomous integrity monitoring (ARAIM) algorithm.

10. The system of claim 2 , wherein the integrity monitoring is implemented as part of an advanced receiver autonomous integrity monitoring (ARAIM) algorithm.

11. The system of claim 2 , wherein the receiver is configured to receive signals from a global navigation satellite system (GNSS).

12. The system of claim 2 , wherein the receiver is configured to receive signals from a multi-constellation, multi-frequency GNSS.

13. The system of claim 2 wherein the inertial sensors are implemented in an inertial measurement unit.

14. The system of claim 2 , further comprising one or more additional sensors in operative communication with the processor.

15. The system of claim 2 , wherein the system is onboard an aircraft.

Assignees

• Honeywell Int Inc

Inventors

• Dunik Jindrich
• Orejas Martin
• Kana Zdenek

Classifications

• G01S19/20 Primary

  Integrity monitoring, fault detection or fault isolation of space segment · CPC title

• G01S19/47

  the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial · CPC title

• G01C21/165

  combined with non-inertial navigation instruments · CPC title