METHODS AND SYSTEMS FOR DETERMINING LOCATION USING A CELLULAR AND WLAN POSITIONING SYSTEM BY SELECTING THE BEST WLAN PS SOLUTION

• US 20090310585A1
• Filed: 06/16/2009
• Published: 12/17/2009
• Est. Priority Date: 06/16/2008
• Status: Active Grant

• Current Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Original Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Inventors: Alizadeh-Shabdiz, Farshid
• Granted Patent: US 8,462,745 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: G01S 5/0244 Accuracy or reliability of position solution or of measurements contributing thereto
• CPC Class Codes: G01S 5/0263 by combining or switching between positions derived from two or more separate positioning systems
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

The disclosed subject matter relates to a method and system for increasing the accuracy of a WLAN based position estimate using cellular positioning information. In some embodiments, the method can include determining a set of possible WLAN location solutions for a WLAN and cellular enabled device based on one or more WLAN access points, obtaining cellular measurements from at least one cell tower, and determining the best WLAN location solution from the set of possible WLAN location solutions using the cellular measurements. In one embodiment, the method can include using the cellular measurements from the at least one cell tower to provide a cellular based location estimate for the WLAN and cellular enabled device.

Claims

1. A method of increasing the accuracy of a WLAN based position estimate using cellular positioning information, the method comprising:

determining a set of possible WLAN location solutions for a WLAN and cellular enabled device based on one or more WLAN access points;

obtaining cellular measurements from at least one cell tower; and

determining the best WLAN location solution from the set of possible WLAN location solutions using the cellular measurements.

2. The method of claim 1 comprising using the cellular measurements from the at least one cell tower to provide a cellular based location estimate for the WLAN and cellular enabled device.

3. The method of claim 2 comprising determining the best WLAN location solution from the set of possible WLAN location solutions using the cellular based location estimate.

4. The method of claim 3, wherein determining the best WLAN location solution from the set of possible WLAN location solutions using the cellular based location estimate comprises:

determining a distance between each of the possible WLAN location solutions and the cellular based location estimate; and

selecting the best WLAN location solution based on which of the possible WLAN location solutions is within an expected error of the cellular based location estimate.

5. The method of claim 3, wherein the step of determining the best WLAN location solution from the set of possible WLAN location solutions using the cellular based location estimate comprises:

eliminating possible WLAN location solutions which are far from cellular based location estimate.

6. The method of claim 3, wherein the set of possible WLAN location solutions comprises a WLAN access point cluster.

7. The method of claim 6, comprising weighing the WLAN access point clusters according to the distance from each WLAN location solution to the cellular based location estimate.

8. The method of claim 7 further comprising selecting WLAN location solutions having a small distance to the cellular based location estimate.

9. The method of claim 8, wherein the small distance is on the order of a hundred meters.

10. The method of claim 7 comprising eliminating WLAN location solutions having a large distance to the cellular location solution.

11. The method of claim 10, wherein the large distance is on the order of tens of kilometers.

12. The method of claim 1, wherein each WLAN location solution in the set of possible WLAN location solutions corresponds to a location of a WLAN access point.

13. The method of claim 12, comprising:

comparing the location of each WLAN access point to the known location of the WLAN access point stored in a WLAN reference database; and

if the location of the WLAN access point does not correspond to the known location of the WLAN access point in the WLAN reference database, determining that the WLAN access point has moved.

14. The method of claim 13 comprising updating the known location of the WLAN access point in the WLAN reference database to correspond to the location of the WLAN access point.

15. The method of claim 3, wherein the cellular measurements comprise a cell ID of the cell tower.

16. The method of claim 15 comprising:

accessing a cellular reference database containing cell tower reference locations for each cell ID;

comparing the cell tower reference location to the cellular based location estimate; and

if the cell tower reference location and the cellular based location do not match, informing the cellular reference database that the locations do not match.

17. The method of claim 16 comprising updating the cellular reference database with the cellular based location.

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

a positioning module comprising;

a WLAN module for receiving information from one or more WLAN access points;

a cellular positioning module for obtaining cellular measurements from at least one cell tower;

logic located in the WLAN module to determine a set of possible WLAN location solutions for a WLAN and cellular enabled device based on one or more WLAN access points; and

logic located in the positioning module to use the cell tower information to determine the best WLAN location solution from the set of possible WLAN location solutions using the cell tower information.

19. The system of claim 18 comprising logic located in the cellular positioning module to use the cellular measurements from the at least one cell tower to provide a cellular based location estimate for the WLAN and cellular enabled device.

20. The method of claim 19 comprising logic in the positioning module to determine the best WLAN location solution from the set of possible WLAN location solutions using the cellular based location estimate.

21. The method of claim 20, wherein the set of possible WLAN location solutions comprises a WLAN access point cluster.

22. The method of claim 21, comprising weighing the WLAN access point cluster according to the distance from each WLAN location solution to the cellular based location estimate.