Methods and systems for location estimation

• US 20060240839A1
• Filed: 04/25/2005
• Published: 10/26/2006
• Est. Priority Date: 04/25/2005
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Feng, Kai-Ten, Chen, Chao-Lin
• Granted Patent: US 7,257,412 B2
• Time in Patent Office: Days
• US Class Current: 455/456.100
• 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
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial

Abstract

Methods and systems for location estimation. Signals are received from a plurality of satellites and a plurality of base stations by a mobile station. The location of the mobile station is estimated according to TOA (Time-Of-Arrival) and TDOA (Time Difference-Of-Arrival) measurements calculated based on the signals.

Claims

1. A method for location estimation of a mobile device, comprising:

performing TOA (Time-Of-Arrival) measurements according to signals from a plurality of satellites;

estimating a first position using an expansion method based on the TOA measurements;

performing TDOA (Time Difference-Of-Arrival) measurements according to signals from a plurality of base stations;

estimating a second position using the expansion method based on the TDOA measurements; and

incorporating the first and second positions to estimate the location of the mobile station.

2. The method of claim 1 further comprising:

smoothing the first and second positions by a filtering technique.

3. The method of claim 2 wherein the filtering technique is Kalman filtering.

4. The method of claim 1 further comprising:

performing an AOA (Angle-Of-Arrival) measurement by a specific base station; and

estimating the second position using the expansion method based on the TDOA and AOA measurements.

5. The method of claim 4 wherein the specific base station is a home base station of the mobile device.

6. The method of claim 4 further comprising:

determining whether the distance between the mobile device and the specific base station is above a threshold.

7. The method of claim 1 further comprising:

estimating the first position using the expansion method based on the TOA measurements and the locations of respective satellites.

8. The method of claim 1 further comprising:

estimating the second position using the expansion method based on the TDOA measurements and the locations of respective base stations.

9. The method of claim 1 wherein the expansion method is two-step Least Square (LS) method.

10. The method of claim 1 wherein the first and second positions are incorporated by a Bayestian statistical inference model to estimate the location of the mobile station.

11. A method for location estimation of a mobile station, comprising:

receiving signals from a plurality of satellites and a plurality of base stations; and

estimating the location of the mobile station.

12. The method of claim 11 further comprising:

performing TOA (Time-Of-Arrival) measurements according to the signals from a plurality of satellites;

performing TDOA (Time Difference-Of-Arrival) measurements according to the signals from a plurality of base stations; and

estimating the location of the mobile station according to the TOA and TDOA measurements.

13. The method of claim 12 wherein the TOA and TDOA measurements are incorporated by a Bayestian statistical inference model to estimate the location of the mobile station.

14. The method of claim 12 further comprising:

performing an AOA (Angle-Of-Arrival) measurement by a specific base station; and

estimating the location of the mobile station according to the TOA, TDOA, and AOA measurements.

15. The method of claim 14 wherein the TOA, TDOA, and AOA measurements are incorporated by a Bayestian statistical inference model to estimate the location of the mobile station.

16. The method of claim 14 further comprising:

determining whether the distance between the mobile station and the specific base station is above a threshold.

17. The method of claim 14 wherein the specific base station is a home base station of the mobile device.

18. The method of claim 12 further comprising:

smoothing the estimation according to the TOA and TDOA measurements by a filtering technique.

19. The method of claim 18 wherein the filtering technique is Kalman filtering.

20. The method of claim 14 further comprising:

smoothing the estimation according to the TOA, TDOA and AOA measurements by a filtering technique.

21. The method of claim 20 wherein the filtering technique is Kalman filtering.

22. The method of claim 12 further comprising:

estimating the location of the mobile station using an expansion method based on the TOA and TDOA measurements and the locations of respective satellites and base stations.

23. The method of claim 22 wherein the expansion method is two-step Least Square (LS) method.

24. The method of claim 14 further comprising:

estimating the location of the mobile station using an expansion method based on the TOA, TDOA, and AOA measurements and the locations of respective satellites and base stations.

25. The method of claim 24 wherein the expansion method is two-step Least Square (LS) method.

26. A system for location estimation, comprising:

a plurality of satellites;

a plurality of base stations; and

a mobile station, performing TOA (Time-Of-Arrival) measurements according to signals from the satellites, estimating a first position using an expansion method based on the TOA measurements, performing TDOA (Time Difference-Of-Arrival) measurements according to signals from the base stations, estimating a second position using the expansion method based on the TDOA measurements, and incorporating the first and second positions to estimate the location thereof.

27. The system of claim 26 wherein the mobile station further performs a filtering technique on the first and second positions, respectively, thus to smooth measurement noise therefrom.

28. The system of claim 27 wherein the filtering technique is Kalman filtering.

29. The system of claim 26 wherein a specific base station further receives signals sent from the mobile station, performs an AOA (Angle-Of-Arrival) measurement accordingly, and transmits the AOA measurement to the mobile station.

30. The system of claim 29 wherein the specific base station is a home base station of the mobile station.

31. The system of claim 29 wherein one of the base stations further determines whether the distance between the mobile device and the specific base station is above a threshold.

32. The system of claim 29 wherein the mobile station further estimates the second position using the expansion method based on the TDOA and AOA measurements.

33. The system of claim 26 wherein the mobile station estimates the first position using the expansion method based on the TOA measurements and the locations of respective satellites.

34. The system of claim 26 wherein the mobile station estimates the second position using the expansion method based on the TDOA measurements and the locations of respective base stations.

35. The system of claim 26 wherein the expansion method is two-step Least Square (LS) method.

36. The system of claim 26 wherein the first and second positions are incorporated by a Bayestian statistical inference model to estimate the location of the mobile station.

37. A system for location estimation, comprising:

a plurality of satellites;

a plurality of base stations; and

a mobile station, performing TOA (Time-Of-Arrival) measurements according to signals from the satellites, estimating a first position using a two-step Least Square (LS) method based on the TOA measurements, performing TDOA (Time Difference-Of-Arrival) measurements according to signals from the base stations, and transmitting the first position and the TDOA measurements to a specific base station,

wherein the specific base station estimates a second position using the two-step Least Square (LS) method based on the TDOA measurements, and incorporates the first and second positions to estimate the location of the mobile station.

38. The system of claim 37 wherein the specific base station is a home base station of the mobile station.

39. The system of claim 37 wherein the specific base station further smoothes the first and second positions by a Kalman filtering method.

40. The system of claim 37 wherein the specific base station further, performs an AOA (Angle-Of-Arrival) measurement according to signals from the mobile station, and estimates the second position using the two-step Least Square (LS) method based on the TDOA and AOA measurements.

41. The system of claim 37 wherein the specific base station incorporates the first and second positions by a Bayestian statistical inference model.

42. A device, comprising:

means for performing TOA (Time-Of-Arrival) measurements according to signals from a plurality of satellites;

means for estimating a first position based on the TOA measurements;

means for performing TDOA (Time Difference-Of-Arrival) measurements according to signals from a plurality of base stations;

means for estimating a second position based on the TDOA measurements; and

means for incorporating the first and second positions to estimate the location of the device.

43. The device of claim 42 wherein the incorporating means incorporates the first and second positions by a Bayestian statistical inference model.

44. A device, comprising:

means for performing TOA (Time-Of-Arrival) measurements according to signals from a plurality of satellites;

means for estimating a first position based on the TOA measurements;

means for performing TDOA (Time Difference-Of-Arrival) and AOA (Angle-Of-Arrival) measurements according to signals from a plurality of base stations; and

wherein a home base station of the device estimates a second position based on the TDOA and AOA measurements, and incorporates the first and second positions to estimate the location of the device.

45. A device, comprising means for estimating the location of the device according to signals from a plurality of satellites and a plurality of base stations.