Systems for and methods of determining likelihood of relocation of reference points in a positioning system

• US 8,983,504 B2
• Filed: 03/10/2014
• Issued: 03/17/2015
• Est. Priority Date: 06/11/2010
• Status: Active Grant

• Current Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Original Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Inventors: Alizadeh-Shabdiz, Farshid, Brachet, Nicolas, Cavanaugh, Gerald, Dancus, Andrei, Jones, Russel K., Steger, Christopher
• Primary Examiner(s): ZEWDU, MELESS NMN
• Application Number:
  US14/202,072
• Publication Number:
  US 20140256349A1
• Time in Patent Office: 372 Days
• Field of Search: 455/16, 455/67.11, 455/404.2, 455410-420, 455/422.1, 455423-425, 455440-441, 4554561-4566, 455/457, 455/500, 455/501, 455/514, 455524-525, 455/403, 455433-434, 455/461, 455/550.1, 455/445.2, 455560-561, 701445-448, 701/454, 701/461, 701467-473, 701/495, 701520-521
• US Class Current: 455/456.5
• CPC Class Codes: G01S 1/024 of beacon transmitters
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/0252 Radio frequency fingerprinting
• CPC Class Codes: G01S 5/0278 involving statistical or probabilistic considerations G01S5/0252, G01S5/0294 take precedence
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Systems for and methods of determining likelihood of relocation of reference points in a positioning system are disclosed. A method of determining a measure of likelihood that an estimated geographic location of a designated wireless device is not its accurate present location includes determining a set of reference points associated with the device, which are a geographic position at which signals from the device were detected and/or other devices having a relationship with the designated device. The existence of the relationship is based on the devices being within signal reception range of a same position within a selected period of time. The method includes retrieving attributes of the reference points and/or of the relationships and determining a measure of likelihood that an estimated geographic location associated with the designated device is not its present location based on the attributes of the reference points of the set and/or of the relationships.

Claims

1. A method of determining that an estimated geographic location associated with a designated wireless device is not an accurate present location of the designated wireless device and using the determination that the estimated geographic location is not the accurate present location in a wireless positioning system, the method comprising:

determining the estimated geographic location associated with the designated wireless device based on a set of reference points associated with the designated wireless device, each reference point being (i) a geographic position at which signals from the designated wireless device were detected or (ii) another wireless device;

selecting, by the wireless positioning system, one or more other wireless devices or clusters of wireless devices having a relationship with the designated wireless device, the relationship based on the designated wireless device and the respective wireless device being within signal reception range of a receiver within a selected period of time,

based on the estimated geographic location of the designated wireless device and locations of the one or more other wireless devices or clusters of wireless devices, determining that the estimated geographic location associated with the designated wireless device is not the accurate present location of the designated wireless device; and

in response to the determining that the estimated geographic location is not the accurate present location, excluding the designated wireless device from being used by the wireless positioning system as a beacon for estimating a location of a client device.

2. The method of claim 1, wherein the selecting one or more other wireless devices or clusters of wireless devices is based on a stability measure, the stability measure indicating a relative likelihood that location information associated with the respective wireless device is an accurate present location of the respective wireless device.

3. The method of claim 2, wherein the selecting selects one or more other wireless devices, and the determining that the estimated geographic location associated with the designated wireless device is not the accurate present location further comprises:

determining a distance from the estimated geographic location associated with the designated wireless device to the locations of the one or more other wireless devices.

4. The method of claim 3, wherein the determining that the estimated geographic location associated with the designated wireless device is not the accurate present location further comprises:

selecting at least one wireless device of the one or more other wireless devices whose determined distance exceeds a distance threshold;

selecting at least one wireless device of the one or more other wireless devices having a quiet time relationship to the designated wireless device that is less than a quiet time threshold; and

determining that at least one same wireless devices is selected based on distance exceeding the distance threshold and based on the quiet time being less than the quiet time threshold.

5. The method of claim 2, wherein the selecting selects one or more clusters of wireless devices, and the determining that the estimated geographic location associated with the designated wireless device is not the accurate present location further comprises:

determining a distance from the estimated geographic location associated with the designated wireless device to the locations of the one or more clusters of wireless devices.

6. The method of claim 5, wherein the determining that the estimated geographic location associated with the designated wireless device is not the accurate present location of the designated wireless device further comprises:

selecting at least one clusters of wireless devices having a determined distance within a distance threshold;

selecting at least one cluster of wireless devices having a quiet time relationship to the designated wireless device that is less than a quiet time threshold; and

determining that at least one same cluster of wireless devices is selected based on the determined distance being within the distance threshold and based on the quiet time being less than the quiet time threshold.

7. The method of claim 1, wherein the selecting selects one or more clusters of wireless devices and the determining that the estimated geographic location associated with the designated wireless device is not the accurate present location further comprises:

selecting a cluster having a location that corresponds to the estimated geographic location associated with the designated wireless device; and

using a joint stability value of the selected cluster, wherein the joint stability value indicates whether the selected cluster reflects a current geographic location of the designated wireless device.

8. The method of claim 1, wherein the selecting selects one or more other wireless devices and the determining that the estimated geographic location associated with the designated wireless device is not the accurate present location further comprises:

determining a distance from the estimated geographic location associated with the designated wireless device to the locations of the one or more other wireless devices;

weighting each distance based on a quiet time; and

determining a weighted distance threshold is exceeded.

9. The method of claim 1, wherein the selecting selects one or more other wireless devices the determining that the estimated geographic location associated with the designated wireless device is not the accurate present location further comprises:

determining a distance from the estimated geographic location associated with the designated wireless device to locations of the one or more other wireless devices;

selecting at least one wireless device of the one or more other wireless devices within a distance threshold of the estimated geographic location associated with the designated wireless device as a home cluster;

determining a number of wireless devices in the home cluster;

determining a minimum quiet time for wireless devices of the home cluster; and

applying a function to the number of wireless devices and the minimum quiet time.

10. The method of claim 1, wherein the wireless devices are Wi-Fi access points, and the wireless positioning system is a Wi-Fi positioning system.

11. A method of determining that an estimated geographic location associated with a designated wireless device is not an accurate present location of the designated wireless device, and using the determination that the estimated geographic location is not the accurate present location in a wireless positioning system, the method comprising:

determining the estimated geographic location associated with the designated wireless device;

selecting, by the wireless positioning system, one or more other wireless devices or clusters of wireless devices having a relationship with the designated wireless device, the relationship based on the designated wireless device and the respective wireless device being within signal reception range of a receiver within a selected period of time,

based on the estimated geographic location associate with the designated wireless device and locations of the one or more other wireless devices or clusters of wireless devices, determining that the estimated geographic location associated with the designated wireless device is not the accurate present location of the designated wireless device; and

using the determination that the estimated geographic location is not the accurate present location by the wireless positioning system when estimating a location of a client device.

12. The method of claim 11, wherein the selecting selects one or more other wireless devices, and the determining that the estimated geographic location associated with the designated wireless device is not the accurate present location further comprises:

determining a distance from the estimated geographic location of the designated wireless device to the locations of the one or more other wireless devices.

13. The method of claim 12, wherein the determining that the estimated geographic location associated with the designated wireless device is not the accurate present location further comprises:

selecting at least one wireless device of the one or more other wireless devices whose determined distance exceeds a distance threshold;

selecting at least one wireless device of the one or more other wireless devices having a quiet time relation to the designated wireless device that is less than a quiet time threshold; and

determining that at least one same wireless devices is selected based on distance exceeding the distance threshold and based on the quiet time being less than the quiet time threshold.

14. The method of claim 11, wherein the selecting selects one or more clusters of wireless devices, and the determining that the estimated geographic location associated with the designated wireless device is not the accurate present location further comprises:

determining a distance from the estimated geographic location associated with the designated wireless device to the locations of the one or more clusters of wireless devices.

15. The method of claim 14, wherein the determining that the estimated geographic location associated with the designated wireless device is not the accurate present location further comprises:

selecting at least one cluster of wireless devices having a determined distance within a distance threshold;

selecting at least one cluster of wireless devices having a quiet time relationship to the designated wireless device that is less than a quiet time threshold; and

determining that at least one same cluster of wireless devices is selected based on the determined distance being within the distance threshold and based on the quiet time being less than the quiet time threshold.

16. The wireless positioning system of claim 15 wherein the one or more other wireless devices or clusters of wireless devices are one or more other wireless devices and the instructions when executed by the computer system further cause the computer system to:

determine a distance from the estimated geographic location of the designated wireless device to the locations of the one or more other wireless devices.

17. The wireless positioning system of claim 16, wherein the instructions when executed by the computer system further cause the computer system to:

select at least one wireless device of the one or more other wireless devices whose determined distance exceeds a distance threshold,

select at least one wireless device of the one or more other wireless devices having a quiet time relationship to the designated wireless device that is less than a quiet time threshold, and

determine that at least one same wireless devices is selected based on distance exceeding the distance threshold and based on the quiet time being less than the quiet time threshold.

18. The wireless positioning system of claim 15, wherein the one or more other wireless devices or clusters of wireless devices are one or more clusters of wireless devices and the instructions when executed by the computer system further cause the computer system to:

determine a distance from the estimated geographic location of the designated wireless device to the locations of the one or more clusters of wireless devices.

19. The wireless positioning system of claim 18, wherein the instructions when executed by the computer system further cause the computer system to:

select at least one cluster of wireless devices having a determined distance within a distance threshold;

select at least one cluster of wireless devices having a quiet time relation to the designated wireless device that is less than a quiet time threshold; and

determine that at least one same cluster of wireless devices is selected based on the determined distance being within the distance threshold and based on the quiet time being less than the quiet time threshold.

20. A wireless positioning system configured to determine that an estimated geographic location associated with a designated wireless device is not an accurate present location of the designated wireless device, and use the determination that the estimated geographic location is not the accurate present location, comprising:

a computer system configured to estimate a location of a client device based on one or more beacons whose signals are observed by the client device; and

a non-transitory computer readable media including instructions that when executed by the computer system cause the computer system to

determine an estimated geographic location of the designated wireless device,

select one or more other wireless devices or clusters of wireless devices having a relationship with the designated wireless device,

based on the estimated geographic location of the designated wireless device and locations of the one or more other wireless devices or clusters of wireless devices, determine that the estimated geographic location associated with the designated wireless device is not the accurate present location of the designated wireless device, and

in response to the determination that the estimated geographic location associated with the designated wireless device is not the accurate present location, exclude the designated wireless device from being used by the wireless positioning system as a beacon for estimating the location of the client device.