Systems and Methods for Detecting GPS Measurement Errors

• US 20090128407A1
• Filed: 11/20/2007
• Published: 05/21/2009
• Est. Priority Date: 11/20/2007
• Status: Active Grant

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Chansarkar, Mangesh, Xie, Gang, Lin, Xiangdong, Liao, Daniel
• Granted Patent: US 7,821,454 B2
• Time in Patent Office: Days
• US Class Current: 342/357.580
• CPC Class Codes: G01S 19/20 Integrity monitoring, fault detection or fault isolation of space segment

Abstract

Systems and methods for detecting global positioning system (GPS) measurement errors are provided. In this regard, a representative system, among others, includes a navigation device that is configured to receive GPS signals from signal sources, the navigation device being configured to calculate pseudoranges (PRs) and delta ranges (DRs) based on the received GPS signals, the navigation device including a consistency check algorithm that is configured to: determine mismatches between the respective calculated PRs and DRs, and indicate that an error exists in the respective calculated PRs and DRs based on their mismatch and mismatch accumulations. This algorithm can be independent of navigation state and is capable of detecting slow-changing errors.

Claims

1. A system for detecting global positioning system (GPS) measurement errors comprising:

a navigation device that is configured to receive GPS signals from signal sources, the navigation device being configured to calculate pseudoranges (PRs) and delta ranges (DRs) based on the received GPS signals, the navigation device including a consistency check algorithm that is configured to;

determine mismatches between the respective calculated PRs and DRs, and

indicate that an error exists in the respective calculated PRs and DRs based on at least one of the mismatches.

2. The system as defined in claim 1, wherein the consistency check algorithm is further configured to calculate delta PRs based on the calculated PRs.

3. The system as defined in claim 2, wherein the consistency check algorithm is further configured to determine the differences between the respective calculated delta PRs and DRs.

4. The system as defined in claim 3, wherein the consistency check algorithm is further configured to:

determine whether at least one of the differences between the respective calculated delta PRs and DRs exceeded a first threshold; and

responsive to determining that the at least one of the differences exceeded the first threshold, indicate that an error exists in the respective calculated PRs and DRs associated with the at least one of the mismatches that exceeded the first threshold.

5. The system as defined in claim 4, wherein the consistency check algorithm is further configured to accumulate the differences between the respective calculated delta PRs and DRs.

6. The system as defined in claim 5, wherein the consistency check algorithm is further configured to:

determine whether the accumulation of the differences between the respective calculated delta PRs and DRs exceeded a second threshold; and

responsive to determining that the accumulation of the differences exceeded the second threshold, indicate that an error exists in the respective calculated PRs and DRs.

7. The system as defined in claim 1, wherein the consistency check algorithm is further configured to send an error message to a navigation algorithm responsive to determining that the at least one of the mismatches exceeded a mismatch threshold.

8. The system as defined in claim 1, wherein the consistency check algorithm is further configured to send the calculated PR and DR to a navigation algorithm responsive to determining that the at least one of the mismatches did not exceed a mismatch threshold.

9. A method global positioning system (GPS) measurement errors comprising:

receiving GPS signals from signal sources;

calculating pseudoranges (PR) and delta ranges (DR) based on the received GPS signals;

determining mismatches between the respective calculated PRs and DRs; and

indicating that an error exists in the respective calculated PRs and DRs based on at least one of the mismatches.

10. The method as defined in claim 9, further comprising calculating a delta PR based on the calculated PR.

11. The method as defined in claim 10, further comprising determining the difference between the calculated delta PR and DR.

12. The method as defined in claim 11, further comprising:

determining whether at least one of the differences between the respective calculated delta PRs and DRs exceeded a first threshold; and

responsive to determining that the at least one of the differences exceeded the first threshold, indicating that an error exists in the respective calculated PRs and DRs.

13. The method as defined in claim 12, further comprising accumulating the differences between the calculated delta PR and DR.

14. The method as defined in claim 13, further comprising:

determining whether the accumulation of the differences between the respective calculated delta PRs and DRs exceeded a second threshold; and

responsive to determining that the accumulation of the differences exceeded the second threshold, indicating that an error exists in the respective calculated PRs and DRs.

15. The method as defined in claim 9, further comprising sending an error message to a navigation algorithm responsive to determining that the at least one of the mismatches exceeded a mismatch threshold.

16. The method as defined in claim 9, further comprising sending the calculated PR and DR to a navigation algorithm responsive to determining that the at least one of the mismatches did not exceed a mismatch threshold.

17. A global positioning system (GPS) receiver comprising:

an antenna that receives GPS signals from signal sources;

a digital signal processing (DSP) that receives the GPS signals from the antenna, the DSP being configured to calculate pseudoranges (PRs) and delta ranges (DRs) based on the received GPS signals; and

a consistency check algorithm that is configured to;

determine mismatches between the respective calculated PRs and DRs, and

indicate that an error exists in the respective calculated PRs and DRs based on at least one of the mismatches.

18. The GPS receiver as defined in claim 17, wherein the consistency check algorithm is further configured to:

calculate delta PRs based on the calculated PRs,

determine the differences between the respective calculated delta PRs and DRs,

determine whether at least one of the differences between the respective calculated delta PRs and DRs exceeded a first threshold, and

responsive to determining that the at least one of the differences exceeded the first threshold, indicating that an error exists in the respective calculated PRs and DRs.

19. The GPS receiver as defined in claim 18, wherein the consistency check algorithm is further configured to:

accumulate the differences between the respective calculated delta PRs and DRs,

determine whether the accumulation of the differences between the respective calculated delta PRs and DRs exceeded a second threshold; and

responsive to determining that the accumulation of the differences exceeded the second threshold, indicate that an error exists in the respective calculated PRs and DRs.

20. The GPS receiver as defined in claim 18, wherein the consistency check algorithm is further configured to send the calculated PR and DR to a navigation algorithm responsive to determining that the at least one of the mismatches exceeded a mismatch threshold.

21. A global positioning system (GPS) receiver comprising:

an antenna that receives GPS signals from signal sources;

a digital signal processing (DSP) that receives the GPS signals from the antenna, the DSP being configured to calculate pseudoranges (PRs) and delta ranges (DRs) based on the received GPS signals; and

a consistency check algorithm that is configured to;

accumulate the differences between the respective calculated delta PRs and DRs,

determine whether the accumulation of the differences between the respective calculated delta PRs and DRs exceeded a second threshold; and

responsive to determining that the accumulation of the differences exceeded the second threshold, indicate that an error exists in the respective calculated PRs and DRs.