Integrated navigation system

• US 6,377,892 B1
• Filed: 05/02/2000
• Issued: 04/23/2002
• Est. Priority Date: 05/02/2000
• Status: Expired due to Term

• Current Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: McElreath, Kenneth W., Johnson, Cris W.
• Primary Examiner(s): Beaulieu, Yonel
• Application Number:
  US09/563,311
• Time in Patent Office: 721 Days
• Field of Search: 701/200, 701/207, 701/211, 701/213, 701/214, 701/215, 701/220, 701/221, 342/357.01, 342/357.02, 342/357.08, 342/357.12, 731/78.T
• US Class Current: 701/213
• CPC Class Codes: G01S 19/08 providing integrity information, e.g. health of satellites or quality of ephemeris data
• CPC Class Codes: G01S 19/15 Aircraft landing systems
• CPC Class Codes: G01S 19/18 Military applications
• CPC Class Codes: G01S 19/20 Integrity monitoring, fault detection or fault isolation of space segment

Abstract

An integrated navigation system includes a prime mission navigation system (e.g., a military code GPS-based flight management system), a second navigation system (e.g., a civil code GPS-based navigation system) and an integrity check system. The first navigation system receives first positioning signals and generates a first navigation solution based on the first positioning signals. The second navigation system receives second positioning signals and generates a second navigation solution based on the second positioning signals. The integrity check system receives the first navigation solution and the second navigation solution, compares the first navigation solution to the second navigation solution, and generates a validity signal based on the comparison.

Claims

1. An integrated navigation system, comprising:

a first navigation system configured to receive first positioning signals and to generate a first navigation solution based on the first positioning signals;

a second navigation system configured to receive second positioning signals and to generate a second navigation solution based on the second positioning signals; and

an integrity check system configured to receive the first navigation solution and the second navigation solution, to compare the first navigation solution to the second navigation solution, and to generate a validity signal indicating that one of the first and second navigation solutions is invalid based on the comparison.

2. The integrated navigation system of claim 1, wherein the second navigation system includes a civil code GPS receiver.

3. The integrated navigation system of claim 2, wherein the first navigation system includes a military code GPS receiver.

4. The integrated navigation system of claim 3, wherein the first positioning signals and the second positioning signals include GPS satellite signals, the second navigation system configured to identify one of the GPS satellite signals as having a fault and to provide a fault signal to the first navigation system, the first navigation system configured to exclude the one GPS satellite from the first navigation solution.

5. The integrated navigation system of claim 1, wherein the validity signal indicates that the first navigation solution is invalid when the first navigation solution is greater than a predetermined distance from the second navigation solution.

6. The integrated navigation solution of claim 5, wherein the validity signal indicates that the first navigation solution is invalid when a mathematical combination of the difference between the first and second navigation solutions and the probable statistical errors of the second navigation solution exceed a predetermined value.

7. The integrated navigation system of claim 5, wherein the predetermined distance is based on a Required Navigation Performance level.

8. The integrated navigation system of claim 1, wherein the second navigation system is configured to determine whether an integrity check is available based on the second positioning signals and to generate an integrity monitor availability signal based on the determination.

9. The integrated navigation system of claim 1, further comprising an indicator selected from the group consisting of a visible indicia and an audible indicia, wherein the indicator is actuated by the validity signal.

10. The integrated navigation system of claim 1, wherein the first navigation system includes a flight management system.

11. The integrated navigation system of claim 1, wherein the first positioning signals include signals from an inertial navigation unit.

12. A system for providing integrity checking for an existing navigation system configured to generate a navigation solution, the system comprising:

a civil code GPS receiver operable in parallel with the existing navigation system, the civil code GPS receiver configured to receive satellite signals and to generate location signals based on the satellite signals; and

means for checking the integrity of the navigation solution and for generating a validity signal representative of the integrity of the navigation solution.

13. The system of claim 12, further comprising means for determining whether integrity monitoring is available and for generating an integrity monitoring availability signal based on the determination.

14. The system of claim 12, the existing navigation system generating a navigation solution, wherein the means for checking compares the location signals to the navigation solution and generates the validity signal based on the comparison.

15. The system of claim 12, the existing navigation system having a GPS receiver, wherein the civil code GPS receiver is located on a data card configured to be inserted into the GPS receiver.

16. The system of claim 12, the existing navigation system configured to receive the satellite signals and to generate first pseudoranges for a plurality of satellite signals, wherein the civil code GPS is configured to generate second psuedoranges, wherein the means for checking compares the first pseudoranges to the second pseudoranges and generates the validity signal based on the comparison.

17. In a navigation system having a military code GPS receiver configured to receive a military satellite signal and to generate first location signals based on the military satellite signals, an improvement for configuring the navigation system for operation in civil airspace, wherein the improvement comprises:

a civil code GPS receiver configured to receive satellite signals having a civil code and to generate second location signals based on the civil code; and

means for receiving the second location signals and using the second location signals to perform a function required of a civil aircraft.

18. The navigation system of claim 17, wherein the function includes Receiver Autonomous Integrity Monitoring (RAIM) and Fault Detection and Exclusion (FDE).

19. The navigation system of claim 17, wherein the function includes Automatic Dependent Surveillance.

20. The navigation system of claim 17, wherein the function includes position reporting among aircraft.

21. A method of checking the integrity of a navigation system generating a first navigation solution based on first positioning data, comprising:

receiving second positioning data different from the first positioning data;

generating a second navigation solution based on the second positioning data;

comparing the second navigation solution to the first navigation solution; and

generating an invalidity signal based on the comparison.

22. The method of claim 21, wherein the second positioning data include civil code GPS data.

23. The method of claim 22, further comprising:

calculating a mathematical combination of the difference between the first and second navigation solutions and the probable statistical errors of the second navigation solution; and

generating the invalidity signal when the mathematical combination exceeds the predetermined value.

24. The method of claim 23, further comprising periodically reporting one of the first navigation solution and the second navigation solution to a ground based station.

25. The method of claim 24, further comprising periodically reporting one of the first navigation solution and the second navigation solution to nearby aircraft.

26. An integrated navigation system, comprising:

a first receiver configured to receive GPS satellite signals and to generate a first navigation solution;

a second receiver configured to receive the GPS satellite signals, the second receiver having a fault detection and exclusion algorithm configured to identify a faulty GPS satellite signal and to provide a fault signal to the first receiver, the first receiver configured to exclude the faulty GPS satellite signal from the navigation solution.

27. The integrated navigation system of claim 26, wherein the first receiver is configured to generate the first navigation solution based on the military code of the GPS satellite signals.

28. The integrated navigation system of claim 27, wherein the second receiver is configured to generate the second navigation solution based on the civil code of the GPS satellite signals.

29. The integrated navigation system of claim 28, wherein the second receiver includes means for performing a function required of a civil aircraft.

30. The integrated navigation system of claim 29, wherein the function includes integrity monitoring.