Self-positioning of a wireless station

• US 8,606,188 B2
• Filed: 11/19/2010
• Issued: 12/10/2013
• Est. Priority Date: 11/19/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Venkatraman, SaiPradeep
• Primary Examiner(s): NGUYEN, TUAN HOANG
• Application Number:
  US12/950,950
• Publication Number:
  US 20120129461A1
• Time in Patent Office: 1,117 Days
• Field of Search: 455/67.11, 455/456.1, 455/456.3, 455/404.2, 340/539.2, 340/539.13, 340/539.15, 342/357.2, 342/357.25, 342/357.34
• US Class Current: 455/67.11
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: G01S 5/0249 Determining position using measurements made by a non-stationary device other than the device whose position is being determined
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 64/003 locating network equipment

Abstract

A self-positioning mechanism is provided that determines and tracks the position of an access point in real time. A location unaware access point determines its location from the locations of location aware stations. The location is determined based on a predicted estimate which is updated based on measured values of the locations of the location aware stations over a time period. The movement of the location is then tracked based on the differences between range measurements of the location aware stations.

Claims

1. A method for tracking a location of an access point, the method comprising:

providing one or more location aware stations in communication with a location unaware access point, each location aware station having a known location, the location unaware access point having an unknown location;

determining a coarse location estimate for the location unaware access point from one or more of the locations of the location aware stations;

refining the coarse location estimate based on range measurement data obtained from one or more of the location aware stations over a time period until the coarse location estimate meets an error tolerance; and

using the refined coarse location estimate as the location of the location unaware access point.

2. The method of claim 1, wherein determining the coarse location estimate further comprises:

estimating the coarse location estimate based on a weighted average of the locations of the location aware stations.

3. The method of claim 2, wherein the weighted average is based on a received signal strength indicator or timing measurements.

4. The method of claim 1, wherein refining the coarse location estimate further comprises:

utilizing an extended Kalman filter (EKF) to refine the coarse location estimate at each time step within the time period until the coarse location estimate meets the error tolerance.

5. The method of claim 1, further comprising:

tracking the location of the location unaware access point relative to current locations of the location aware stations and a current location of the location unaware access point;

determining that the location unaware access point has moved; and

calculating a new location of the location unaware access point.

6. The method of claim 5, wherein determining the coarse location estimate further comprises:

confirming movement of the location unaware access point by sampling range measurements of location aware stations over a second time period.

7. The method of claim 1, further comprising:

providing a test statistic associated with the location of the location unaware access point;

determining if the test statistic indicates movement; and

confirming movement of the location unaware access point by computing one or more additional test statistics over a second time period.

8. The method of claim 7, wherein determining the coarse location estimate further comprises:

comparing the test statistic to a threshold based on a confidence level.

9. The method of claim 1, wherein the known location is a position within one of a satellite positioning system and a wireless communication positioning system.

10. An apparatus for tracking a location of an access point, the apparatus comprising:

a wireless receiver for receiving location and measurement data from one or more location aware stations, the location aware stations in communication with the apparatus, the apparatus having an unknown location; and

a processor coupled to the wireless receiver, wherein the processor is configured to determine the location of the apparatus by weight averaging predicted estimates of the location and measured values of the location, over a time period, until a predicted estimate meets a threshold.

11. The apparatus of claim 10, wherein the measured values are based on measurement data received from one or more location aware stations.

12. The apparatus of claim 10, wherein the processor determines an initial position estimate based on location data received from one or more of the location aware stations, and determines a predicted estimate based on a coarse location estimate as an initial position estimate which is refined at each time step in the time period using measurement data of the location aware stations until the predicted estimate meets the threshold.

13. The apparatus of claim 10, wherein the processor utilizes an extended Kalman filter (EKF) to determine the location of the apparatus.

14. The apparatus of claim 10, wherein the processor tracks for movement of the location of the apparatus based on locations of one or more location aware stations.

15. The apparatus of claim 14, wherein the processor confirms movement of the location of the apparatus by sampling locations of one or more location aware stations over a second time period.

16. A system for tracking a location of an access point, the system comprising:

a wireless communication system;

a positioning system associating a location to each of a plurality of stations and to each of a plurality of access points;

at least one location unaware access point, each location unaware access point having an unknown location, each location unaware access point linked to the wireless communication system, the unknown location associated with the positioning system;

at least one location aware station, each location aware station having a known location, each location aware station linked to the wireless communication system, the known location associated with the positioning system;

wherein the location unaware access point determines an initial estimate of a known location of the location unaware access point based on the locations of the location aware stations and refines the initial estimate using range measurements of the location aware stations over a time period until a location is determined.

17. The system of claim 16, further comprising a location server for storing locations of the location aware stations and/or storing range measurements of the location aware stations.

18. The system of claim 17, wherein the location unaware access point obtains the locations of the location aware stations from the location server.

19. The system of claim 17, wherein the location unaware access point obtains the range measurements of the location aware stations from the location server.

20. The system of claim 17, wherein the positioning system comprises a satellite system or a cellular network.