Method and apparatus for maintaining integrity of long-term orbits in a remote receiver

• US 8,963,773 B2
• Filed: 06/21/2013
• Issued: 02/24/2015
• Est. Priority Date: 11/17/2000
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Global Locate Incorporated (Broadcom, Inc.)
• Inventors: Van Diggelen, Frank, Riben, Matthew
• Primary Examiner(s): Issing, Gregory C
• Application Number:
  US13/924,069
• Publication Number:
  US 20130285851A1
• Time in Patent Office: 613 Days
• Field of Search: 342/357.66, 342/357.4, 342/357.58
• US Class Current: 342/357.66
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/20 Integrity monitoring, fault detection or fault isolation of space segment
• CPC Class Codes: G01S 19/254 relating to Doppler shift of satellite signals
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver

Abstract

A method and apparatus for maintaining integrity of long-term-orbit information used by a Global-Navigation-Satellite-System or other positioning receiver is described. The method comprises obtaining a predicted pseudorange from a first set of long-term-orbit information possessed by a positioning receiver; obtaining, at the positioning receiver from at least one satellite, a measured pseudorange; determining validity of the predicted pseudorange as a function of the predicted pseudorange and the measured pseudorange; and excluding from the long-term-orbit information at least a portion thereof when the validity of the predicted pseudorange is deemed invalid. Optionally, the method may comprise updating or otherwise supplementing the long-term-orbit information with other orbit information if the validity of the predicted pseudorange is deemed invalid.

Claims

1. A method, comprising;

obtaining, for a first receiver, a predicted position-fix generated using current long-term-orbit information and using measured pseudoranges between four satellites and the first receiver, wherein the current long-term-orbit information is valid longer in time than first broadcast ephemeris from the four satellites;

obtaining, for the first receiver, a measured position-fix generated using second broadcast ephemeris from the four satellites and using the measured pseudoranges between the four satellites and the first receiver;

determining, by a processor, a validity of the predicted position-fix based on a difference between the predicted position-fix and the measured position-fix; and

requesting and obtaining fresh long-term-orbit information from a server based on the determination indicating a lack of validity of the predicted position-fix.

2. The method of claim 1, further comprising:

discarding the current long-term-orbit information based on the determination indicating a lack of validity of the predicted position-fix.

3. The method of claim 1, wherein determining the validity of the predicted position-fix comprises:

comparing the difference between the predicted position-fix and the measured position-fix to a threshold.

4. The method of claim 3, further comprising:

excluding at least a portion of the current long-term-orbit information when the difference satisfies the threshold.

5. The method of claim 1, further comprising:

supplementing the current long-term-orbit information based on the determination indicating the lack of validity of the predicted position-fix.

6. The method of claim 1, wherein the current long-term-orbit information is supplemented with the fresh long-term-orbit information.

7. The method of claim 5, wherein determining the validity of the predicted position-fix comprises:

comparing the difference between the predicted position-fix and the measured position-fix to a threshold.

8. The method of claim 3, further comprising:

dynamically setting the threshold.

9. The method of claim 5, wherein the fresh long-term-orbit is more current than the current long-term-orbit information.

10. The method of claim 1, wherein the long-term-orbit information has a validity period greater than the second broadcast ephemeris.

11. A receiver comprising:

a memory configured to store executable instructions;

a processor configured to obtain from the memory the executable instructions and execute the executable instructions to;

obtain a predicted position-fix generated using current long-term-orbit information and using measured pseudoranges between four satellites and the receiver, wherein the current long-term-orbit information is valid longer in time than first broadcast ephemeris from the four satellites;

obtain a measured position-fix generated using second broadcast ephemeris from the four satellites and using the measured pseudoranges between the four satellites and the receiver;

determine a validity of the predicted position-fix based on a difference between the predicted position-fix and the measured position-fix; and

request and obtain fresh long-term-orbit information from a server based on the determination indicating a lack of validity of the predicted position-fix.

12. The receiver of claim 11, wherein the processor is further configured to execute the executable instructions to:

discard the current long-term-orbit information based on the determination indicating the lack of validity of the predicted position-fix.

13. The receiver of claim 11, wherein the processor is further configured to execute the executable instructions to:

supplement the current long-term-orbit information based on the determination indicating the lack of validity of the predicted position-fix.

14. The receiver of claim 11, wherein the current long-term-orbit information is supplemented with the fresh long-term-orbit information.

15. The receiver of claim 11, wherein the processor is configured to determine the validity of the predicted position-fix by comparing the difference between the predicted position-fix and the measured position-fix to a threshold.

16. The receiver of claim 11, further comprising:

a transceiver for sending the request for the fresh long-term-orbit information and for receiving, in response to the request, the fresh long-term-orbit information.

17. A method, comprising:

determining a predicted position-fix generated using current long-term-orbit information and using measured pseudoranges between four satellites and a first receiver, wherein the current long-term-orbit information is valid longer in time than first broadcast ephemeris from the four satellites;

determining a measured position-fix generated using second broadcast ephemeris from the four satellites and using the measured pseudoranges between the four satellites and the first receiver;

determining, by a processor, a validity of the predicted position-fix based on a difference between the predicted position-fix and the measured position-fix; and

requesting and obtaining fresh long-term-orbit information from a server based on the determination indicating a lack of validity of the predicted position-fix.

18. The method of claim 17, further comprising:

discarding the current long-term-orbit information based on the determination indicating the lack of validity of the predicted position fix.

19. The method of claim 17, wherein determining the validity of the predicted position-fix comprises:

comparing the difference between the predicted position-fix and the measured position-fix to a threshold.

20. The method of claim 19, further comprising:

excluding at least a portion of the current long-term-orbit information when the difference satisfies the threshold.