METHOD OF AND SYSTEM FOR INCREASING THE RELIABILITY AND ACCURACY OF LOCATION ESTIMATION IN A HYBRID POSITIONING SYSTEM

• US 20120112958A1
• Filed: 11/03/2011
• Published: 05/10/2012
• Est. Priority Date: 11/03/2010
• Status: Active Grant

• Current Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Original Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Inventors: ALIZADEH-SHABDIZ, Farshid, Heidari, Mohammad A.
• Granted Patent: US 8,890,746 B2
• Time in Patent Office: Days
• US Class Current: 342/357.23
• 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
• CPC Class Codes: G01S 5/0263 by combining or switching between positions derived from two or more separate positioning systems

Abstract

Methods and systems of hybrid positioning are provided for increasing the reliability and accuracy of location estimation. According to embodiments of the invention, the quality of reported locations from specific sources of location is assessed. Satellite and non-satellite positioning systems provide initial positioning estimates. For each positioning system relevant information is collected and based on the collected information each system is assigned appropriate weight.

Claims

1. A method for determining a position of a device using signals from multiple positioning systems, the method comprising:

analyzing signals from at least two of a satellite positioning system (“

SPS”

), a Wi-Fi positioning system, and a cell positioning system (“

CPS”

);

determining for each of the at least two of the SPS, the Wi-Fi positioning system, and the CPS, a corresponding initial position estimate of the device and at least one corresponding parameter; and

selecting one of the corresponding initial position estimates as a final position estimate of the device based on at least one of a history of previously reported positions, the at least one corresponding SPS parameter, the at least one corresponding Wi-Fi positioning system parameter, and the at least one corresponding CPS parameter.

2. The method according to claim 1, wherein each initial position estimate is determined solely from the signals of the corresponding positioning system.

30. The method according to claim 1, wherein selecting one of the corresponding initial position estimates of the device as a final position estimate of the device is according to the distance between the SPS-provided initial position estimate and the Wi-Fi positioning system initial position estimate.

31. The method according to claim 1, wherein selecting one of the corresponding initial position estimates of the device as a final position estimate of the device is according to at least one of a number of satellites used in a fix, a horizontal dilution of precision, a number of Wi-Fi access points used in Wi-Fi positioning, association information to a Wi-Fi access point, and history of previous location estimates.

36. The method according to claim 1, wherein a scanning rate of each of the at least two of a SPS, a Wi-Fi positioning system, and a CPS is individually optimized according to at least one of an association information to a Wi-Fi access point, a velocity of the device, a number of Wi-Fi access points used in Wi-Fi positioning, and a number of satellites used in view

37. The method according to claim 1, further comprising changing the scanning rate for the Wi-Fi positioning system or the CPS if the device is in one-shot or tracking mode.

38. The method according to claim 1, further comprising turning on or off the device based on the device being in one-shot or tracking mode.

39. The method according to claim 1, further comprising changing the scanning rate for the Wi-Fi positioning system or the CPS if the device is connected to an external power supply

40. The method according to claim 1, further comprising:

evaluating the quality of the corresponding initial position estimate of a first positioning system of the at least two of a SPS, a Wi-Fi positioning system, and a CPS; and

selecting the corresponding initial position estimate of the first positioning system as the final position estimate of the device without evaluating the quality of the initial position estimate of a second positioning system of the at least two of a SPS), a Wi-Fi positioning system, and a CPS.

3. A method for determining a position of a device using signals from multiple positioning systems, the method comprising:

analyzing signals from at least two of a satellite positioning system (“

SPS”

), a Wi-Fi positioning system, and a cell positioning system (“

CPS”

);

determining for each of the at least two of the SPS, the Wi-Fi positioning system, and the CPS, a corresponding initial position estimate of the device and corresponding parameters;

selecting one of the corresponding initial position estimates as a final position estimate of the device based on at least one of a history of previously reported positions, the at least one corresponding SPS parameter, the at least one corresponding Wi-Fi positioning system parameter, and the at least one corresponding CPS parameter; and

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on the at least one of the history of the previously reported positions, the at least one corresponding SPS parameter, the at least one corresponding Wi-Fi positioning system parameter, and the at least one corresponding CPS parameter.

4. The method according to claim 3, wherein the SPS initial position is cached for a period of time.

5. A method for determining a position of a device using signals from multiple positioning systems, the method comprising:

analyzing signals from at least two of a satellite positioning system (“

SPS”

), a Wi-Fi positioning system, and a cell positioning system (“

CPS”

);

determining for each of the at least two of the SPS, the Wi-Fi positioning system, and the CPS, a corresponding initial position estimate of the device and corresponding parameters;

assessing for each of the corresponding initial position estimates a quality of the initial position estimate; and

selecting one of the corresponding initial position estimates as a final position estimate of the device based on the assessed qualities of the initial position estimates.

6. The method according to claim 5, wherein an elapsed time to obtain a fix (TTF) is used as an indicator of the quality of the initial position estimate of the SPS.

7. The method according to claim 6, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the TTF.

8. The method according to claim 5, wherein an elapsed time after a fix (TAF) is used as an indicator of the quality of the initial position estimate of the SPS.

9. The method according to claim 8, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the TAF.

10. The method according to claim 5, wherein a combination of a TTF and a TAF is used as an indicator of the quality of the initial position estimate of the SPS.

11. The method according to claim 10, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the combination of a TTF and a TAF.

12. The method according to claim 5, wherein a number of satellites in fix or in view is used as an indicator of the quality of the initial position estimate of the SPS.

13. The method according to claim 12, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the number of satellites in fix or in view.

14. The method according to claim 5, wherein a velocity of the device is used as an indicator of the quality of the initial position estimate of the SPS.

15. The method according to claim 14, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the velocity of the device.

16. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on a combination of at least two of a TTF, a TAF, a number of satellites in fix or in view, and a velocity of the device.

17. The method according to claim 16, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the combination of at least two of the TTF, the TAF, the number of satellites in fix or in view, and the velocity of the device.

18. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on variations in position estimates provided by the SPS.

19. The method according to claim 18, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the variations in position estimates provided by the SPS.

20. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on variations in velocity of the device.

21. The method according to claim 20, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the variations in velocity of the device.

22. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on variations in bearing.

23. The method according to claim 22, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the variations in bearing.

24. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on jumpiness of reported positions by the SPS.

25. The method according to claim 24, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the jumpiness of reported positions by the SPS.

26. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the Wi-Fi positioning system is based on a number of Wi-Fi access points in range of the device.

27. The method according to claim 26, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the number of Wi-Fi access points in range of the device.

28. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the Wi-Fi positioning system is based on a maximum observed power from Wi-Fi access points in range of the device.

29. The method according to claim 28, further comprising

switching to another one of the corresponding initial position estimates as a second final position estimate of the device based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the maximum observed power from Wi-Fi access points in range of the device.

32. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the SPS is based on SPS parameters including at least one of a TTF, a TAF, a number of satellites in fix or in view, a velocity of the vehicle, a HDOP, variations of the TTF, variations of the TAF, variations of the number of satellites in fix or in view, variations of the velocity of the vehicle, and variations of the HDOP.

33. The method according to claim 32, further comprising

turning on or off logic in the device that determines initial position estimates based on an indicator of a type of environment;

changing the scanning rate of the Wi-Fi positioning system and/or the CPS based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the SPS parameters.

34. The method according to claim 5, wherein an indicator of the quality of the initial position estimate of the Wi-Fi positioning system is based on Wi-Fi parameters including at least one of a number of access points in range of the device, a maximum power, statistics of power, quality of Wi-Fi positioning systems, variations of the number of access points in range of the device, variations of the maximum power, variations of the statistics of power, variations of the quality of the initial position estimate of the Wi-Fi positioning systems.

35. The method according to claim 34, further comprising

turning on or off logic in the device that determines initial position estimates based on an indicator of a type of environment;

changing the scanning rate of the Wi-Fi positioning system and/or the CPS based on an indicator of a type of environment;

wherein the indicator of the type of environment is based on the Wi-Fi positioning system parameters.

41. A method for determining a position of a device using signals from multiple positioning systems, the method comprising:

analyzing signals from at least two of a satellite positioning system (“

SPS”

), a Wi-Fi positioning system, and a cell positioning system (“

CPS”

);

determining for each of the at least two of a SPS, Wi-Fi positioning system, and CPS, a corresponding initial position estimate of the device based on the analyzed signals;

combining the corresponding initial position estimates to determine a combined initial position estimate; and

selecting either one of the corresponding initial position estimates of the device or the combined initial position estimate as a final position estimate of the device.

42. A computer-readable storage device containing a set of instructions that causes a mobile device to:

analyze signals from at least two of a satellite positioning system (“

SPS”

), a Wi-Fi positioning system, and a cell positioning system (“

CPS”

);

determine for each of the at least two of a SPS, Wi-Fi positioning system, and CPS, a corresponding initial position estimate of the device based on the analyzed signals; and

select one of the corresponding initial position estimates of the device as a final position estimate of the device.