SYSTEMS AND METHODS FOR USING A SATELLITE POSITIONING SYSTEM TO DETECT MOVED WLAN ACCESS POINTS

• US 20110012780A1
• Filed: 07/16/2009
• Published: 01/20/2011
• Est. Priority Date: 07/16/2009
• 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 8,022,877 B2
• Time in Patent Office: Days
• US Class Current: 342/357.23
• CPC Class Codes: G01S 19/00 Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: G01S 5/0226 Transmitters
• CPC Class Codes: G01S 5/0242 Determining the position of transmitters to be subsequently used in positioning G01S5/0289 takes precedence
• CPC Class Codes: G01S 5/0263 by combining or switching between positions derived from two or more separate positioning systems
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services

Abstract

The disclosed subject matter generally relates to hybrid positioning systems and methods and, more specifically, systems and methods of detecting moved WLAN assess points using a wireless local area network based positioning system (WLAN-PS) and a satellite-based positioning system (SPS) with at least two satellites measurement.

Claims

1. A method of using a WLAN and satellite enabled device is to detect WLAN access points (APs) that have moved, the method comprising:

detecting WLAN APs in range of the WLAN and satellite enabled device;

accessing a reference database to obtain a reference location of each WLAN AP;

obtaining satellite measurements from at least two satellites to provide a plurality of possible SPS location solutions of the device;

calculating a distance between each reference WLAN AP location and the possible SPS location solutions; and

if the distance between the reference WLAN AP location and the SPS location solutions is far, determining that the WLAN AP location in the reference database is not correct.

2. The method of claim 1, comprising notifying the reference database that the WLAN AP location is not correct.

3. The method of claim 1, comprising updating the reference database'"'"'s location for the WLAN AP.

4. The method of claim 1, wherein the possible SPS location solutions of the device comprises a region of possible location solutions for the device.

5. The method of claim 1, wherein the reference WLAN AP location is far from the SPS locations solutions if the distance is an order of magnitude above the coverage area of the AP.

6. The method of claim 1 comprising measuring a consistency between the satellite measurements and the WLAN AP reference location.

7. The method of claim 6, wherein the WLAN AP reference location consistency with the satellite information is measured by applying each of the WLAN AP reference locations to the satellite measurements and calculating an internal SPS receiver clock bias for each WLAN AP reference location.

8. The method of claim 7, wherein a consistency of the internal SPS receiver clock bias for each of the WLAN AP locations is used as an indication of distance between the WLAN AP location and the possible SPS location solutions of the device.

9. The method of claim 8, wherein calculating the consistency of the internal SPS receiver clock bias for each WLAN AP reference location comprises calculating the standard deviation or the mean square error of the internal SPS receiver clock bias.

10. The method of claim 6 comprising calculating an internal SPS receiver clock bias by considering the WLAN AP reference location as an initial position.

11. A system for determining the location of a WLAN and satellite enabled device to detect moved WLAN access points (APs) comprising:

a hybrid positioning module comprising;

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

a satellite positioning module for providing a plurality of possible device locations of the device based on satellite information from at least two different satellites;

a reference database for storing reference locations for each WLAN AP; and

logic contained in the positioning module for calculating a distance between each reference WLAN AP location and the possible SPS location solutions and if the distance between the reference WLAN AP location and the SPS location solutions is far, determining that the reference WLAN AP location is incorrect.

12. The system of claim 11, wherein the possible SPS location solutions of the device comprises a region of possible location solutions for the device.

13. The system of claim 11, wherein the reference WLAN AP location is far from the SPS locations solutions if the distance is an order of magnitude above the coverage area of the AP.

14. The system of claim 11, wherein the logic is configured to measure a consistency between the satellite measurements and the WLAN AP reference location.

15. The system of claim 14, wherein the WLAN AP reference location consistency with the satellite information is measured by applying each of the WLAN AP reference locations to the satellite measurements and calculating an internal SPS receiver clock bias for each WLAN AP reference location.

16. The system of claim 15, wherein a consistency of the internal SPS receiver clock bias for each of the WLAN AP locations is used as an indication of distance between the WLAN AP location and the possible SPS location solutions of the device.

17. The system of claim 16, wherein calculating the consistency of the internal SPS receiver clock bias for each WLAN AP reference location comprises calculating the standard deviation or the mean square error of the internal SPS receiver clock bias.