METHODS AND SYSTEMS FOR IMPROVING THE ACCURACY OF EXPECTED ERROR ESTIMATION IN A HYBRID POSITIONING SYSTEM

• US 20090303113A1
• Filed: 06/05/2009
• Published: 12/10/2009
• Est. Priority Date: 06/06/2008
• Status: Abandoned Application

• Current Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Original Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Inventors: Alizadeh-Shabdiz, Farshid
• Application Number:
  US12/479,727
• Publication Number:
  US 20090303113A1
• Time in Patent Office: Days
• US Class Current: 342/357.480
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system

Abstract

This disclosure describes methods and systems for improving the accuracy of expected error estimation in a hybrid positioning system. In some embodiments, the method of determining an expected error in a location determination of a WLAN and satellite enabled device can include determining a WLAN location estimate and an expected error estimate for the WLAN location estimate, obtaining measurements from at least two satellites, and determining the expected error of the location determination by evaluating the consistency of the satellite positioning system measurements to the WLAN positioning system location estimation.

Claims

1. A method of determining an expected error in a location determination of a WLAN and satellite enabled device, the method comprising:

determining a WLAN location estimate and an expected error estimate for the WLAN location estimate;

obtaining measurements from at least two satellites; and

determining the expected error of the location determination by evaluating the consistency of the satellite positioning system measurements to the WLAN positioning system location estimation.

2. The method of claim 1, wherein consistent measurements between the WLAN location estimate and the satellite positioning system measurements result in a lower expected error in the location determination of the WLAN and satellite enabled device.

3. The method of claim 1, wherein inconsistent measurements between the WLAN location estimate and the satellite positioning system measurements result in a higher expected error in the location determination of the WLAN and satellite enabled device.

4. The method of claim 1, wherein consistency of the measurements comprises the distance between the WLAN positioning system location estimation and a region of possible solutions provided by the satellite positioning system measurements.

5. The method of claim 1, wherein the consistency of the internal SPS receiver clock for the WLAN based location estimate is used as an indication of consistency between the WLAN based location estimate and the satellite positioning system measurements.

6. A method of determining an expected error in a location determination of a WLAN and satellite enabled device, the method comprising:

determining a WLAN based location estimate and an expected error estimate for the WLAN location estimate;

determining a satellite based location estimate and an expected error estimate for the satellite based location estimate; and

determining the expected error of the location determination by evaluating the consistency of the satellite positioning system location estimate to the WLAN positioning system location estimation.

7. The method of claim 6, wherein the location estimate with the lower expected error is selected as the location of the WLAN and satellite enabled device.

8. The method of claim 6, wherein determining the expected error of the location determination comprises comparing the WLAN location estimate and the satellite positioning system location estimate.

9. The method of claim 6, wherein consistent measurements between the WLAN location estimate and the satellite positioning system location estimate result in a lower expected error in the location determination of the WLAN and satellite enabled device.

10. The method of claim 6, wherein inconsistent measurements between the WLAN location estimate and the satellite positioning system location estimate result in a higher expected error in the location determination of the WLAN and satellite enabled device.

11. The method of claim 6, wherein the consistency of the estimates comprises the distance between the satellite positioning system location estimate and the WLAN positioning system location estimation.

12. The method of claim 6, wherein the consistency of the internal SPS receiver clock for the WLAN based location estimate is used as an indication of consistency between the WLAN based location estimate and the satellite positioning system location.

13. A system for increasing the accuracy of a WLAN based position estimate using satellite positioning information, the system comprising:

a positioning module comprising;

a WLAN module for receiving information from one or more WLAN access points to calculate a WLAN location estimate;

a satellite positioning module for obtaining satellite information from at least two different satellites; and

logic located in the positioning module for determining the expected error of the location determination by evaluating the consistency of the satellite positioning system measurements to the WLAN positioning system location estimation.

14. The system of claim 13, wherein consistent measurements between the WLAN location estimate and the satellite positioning measurements result in a lower expected error in the location determination of the WLAN and satellite enabled device.

15. The system of claim 13, wherein inconsistent measurements between the WLAN location estimate and the satellite positioning system measurements result in a higher expected error in the location determination of the WLAN and satellite enabled device.

16. The system of claim 13, wherein consistency of the measurements comprises the distance between the WLAN positioning system location estimation and a region of possible solutions provided by the satellite positioning system measurements.

17. The system of claim 13, wherein the consistency of the internal SPS receiver clock for the WLAN based location estimate is used as an indication of consistency between the WLAN based location estimate and the satellite measurements.

18. A system for increasing the accuracy of a WLAN based position estimate using satellite positioning information, the system comprising:

a positioning module comprising;

a WLAN module for receiving information from one or more WLAN access points and to calculate a WLAN position estimate;

a satellite positioning module for obtaining satellite information from at least four different satellites to calculate a satellite position estimate; and

logic located in the positioning module for determining the expected error of the location determination by evaluating the consistency of the satellite positioning system location estimate to the WLAN positioning system location estimation.

19. The system of claim 18, wherein the consistency of the internal SPS receiver clock for the WLAN based position estimate is used as an indication of consistency between the WLAN based position estimate and the satellite position estimate.

20. The system of claim 18, wherein the position estimate with the lower expected error is selected as the location of the WLAN and satellite enabled device.

21. The system of claim 18, wherein determining the expected error of the location determination comprises comparing the WLAN location estimate and the satellite positioning system location estimate.

22. The system of claim 18, wherein consistent measurements between the WLAN location estimate and the satellite positioning system location estimate result in a lower expected error in the location determination of the WLAN and satellite enabled device.

23. The system of claim 18, wherein inconsistent measurements between the WLAN location estimate and the satellite positioning system location estimate result in a higher expected error in the location determination of the WLAN and satellite enabled device.