Systems for and methods of determining likelihood of atypical transmission characteristics of reference points in a positioning system

• US 9,014,715 B2
• Filed: 06/09/2011
• Issued: 04/21/2015
• 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): Sarwar, Babar
• Application Number:
  US13/156,521
• Publication Number:
  US 20110306357A1
• Time in Patent Office: 1,412 Days
• Field of Search: 455/456.1, 455/418, 455/456.5, 455/456.6, 455/404.2, 455/433, 455/440, 455/441, 455/457, 455/421, 455/422.1
• US Class Current: 455/456.1
• 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 atypical transmission characteristics of reference points in a positioning system are disclosed. A method of determining a measure of likelihood that a designated wireless device exhibits signal transmission characteristics atypical of a wireless device of a type matching the designated device includes determining reference points associated with the designated device, which are a geographic position at which signals from the designated device were detected and/or another wireless device from which signals were also detected by a receiver within a selected period of time during which the signals from the designated device were detected. The method also includes determining statistical measures of a spatial distribution of the reference points and determining a measure of likelihood that the designated device exhibits signal transmission characteristics that are atypical of a wireless device of a type matching the designated device based on the statistical measures.

Claims

1. A method of determining a measure of likelihood that a designated wireless device exhibits signal transmission range that is atypical of a wireless device of a type matching the designated wireless device and using the determination in a wireless positioning system, the method comprising:

determining a set of one or more reference points associated with the designated wireless device, one or more of the reference points being at least one of (i) a geographic position at which signals from the designated wireless device were detected and (ii) another wireless device from which signals were also detected by a receiver within a selected period of time during which the signals from the designated wireless device were detected by the receiver;

determining statistical measures of a spatial distribution of the reference points of the set;

determining a measure of likelihood that the designated wireless device exhibits signal transmission range that is atypical of a wireless device of the type matching the designated wireless device based on the statistical measures of the spatial distribution; and

in response to the measure of likelihood, excluding the designated wireless device from being used by the wireless positioning system as a beacon for estimating a position of a client device.

2. The method of claim 1, the measure of likelihood being a binary decision.

3. The method of claim 1, the measure of likelihood being a probability.

4. The method of claim 1, the determining the statistical measures of the spatial distribution of the reference points including estimating an area of a smallest geometric figure that encompasses estimated geographic locations associated with the reference points.

5. The method of claim 1, further comprising:

each reference point being associated with a reliability value that corresponds to a relative measure of an accuracy of an estimate of a geographic position of the reference point; and

the determining the set of one or more reference points associated with the designated wireless device comprising including within the set only those reference points having a reliability value that is above a threshold value.

6. The method of claim 1, the determining a measure of likelihood that the designated wireless device exhibits signal transmission range that is atypical of a wireless device of the type matching the designated wireless device being further based on an empirical measure of a signal transmission range of a wireless device of the type matching the designated wireless device.

7. The method of claim 1, the determining statistical measures of the spatial distribution of the reference points of the set including determining an estimated distance between the designated wireless device and at least one reference point of the set.

8. The method of claim 7, the determining the measure of likelihood that the designated wireless device exhibits signal transmission range that is atypical of a wireless device of the type matching the designated wireless device being based on a comparison between (i) the distances between the designated wireless device and the reference points of the set and (ii) an empirical measure of a signal transmission range of a wireless device of the type matching the designated wireless device.

9. The method of claim 7, further comprising:

for reference points that are another wireless devices, each of the another wireless devices being associated with a measure of likelihood that the another wireless device of the set exhibits signal transmission range that is atypical of a wireless device of the type matching the another wireless device; and

the determining a set of one or more reference points associated with the designated wireless device comprising including within the set only those another wireless devices having an associated measure of likelihood that the another wireless device exhibits signal transmission range that is atypical of a wireless device of the type matching the another wireless device that is below a threshold value.

10. The method of claim 7, the determining the estimated distances between the designated wireless device and the at least one reference point of the set being based on a geographic location associated with the at least one reference point, and being further based on received signal strength values associated with the signals as detected at the geographic location.

11. The method of claim 7, the designated wireless device being a WiFi-enabled access point.

12. The method of claim 7, the designated wireless device being a mobile telephone transceiver installation.

13. The method of claim 1, the determining statistical measures of the spatial distribution of the reference points of the set including determining a plurality of estimated distances between the designated wireless device and a corresponding plurality of reference points of the set and determining a first distance among the plurality of estimated distances that corresponds to a selected percentile.

14. The method of claim 13, the determining the measure of likelihood that the designated wireless device is exhibiting signal transmission range that is atypical of a wireless device of the type matching the designated wireless device being based on a comparison between (i) the first distance corresponding to the selected percentile and (ii) an empirical measure of a signal transmission range of a wireless device of the type matching the designated wireless device.

15. The method of claim 1, the designated wireless device having a first identifier and the method further comprising determining a second measure of likelihood that a second designated wireless device exhibits signal transmission range that is atypical of a wireless device of a type matching the second designated wireless device based on a comparison of the first identifier and a second identifier associated with the second designated wireless device.

16. The method of claim 1, the designated wireless device having an identifier and the method further comprising associating, in a reference database, the identifier with an indication of the measure of likelihood.

17. The method of claim 1, the designated wireless device being a WiFi-enabled access point.

18. The method of claim 1, the designated wireless device being a mobile telephone transceiver installation.

19. The method of claim 1, for reference points of the set that are another wireless device, the another wireless device of the set being at least one of a WiFi-enabled access point and a mobile telephone transceiver installation.

20. A system for determining a measure of likelihood that a designated wireless device exhibits signal transmission range that is atypical of a wireless device of a type matching the designated wireless device and using the determination in a wireless positioning system, the system comprising:

a computer readable media including instructions that when executed by a computer system cause the computer system to;

determine a set of one or more reference points associated with a designated wireless device, one or more of the reference points being at least one of (i) a geographic position at which signals from the designated wireless device were detected and (ii) another wireless device from which signals were also detected by a receiver within a selected period of time during which the signals from the designated wireless device were detected by the receiver;

determine statistical measures of a spatial distribution of the reference points of the set;

determine a measure of likelihood that the designated wireless device exhibits signal transmission range that is atypical of a wireless device of a type matching the designated wireless device based on the statistical measures of the spatial distribution; and

in response to the measure of likelihood, cause the designated wireless device to be excluded from use as a beacon for estimating a position of a client device by the wireless positioning system.

21. The system of claim 20, the measure of likelihood being a binary decision.

22. The system of claim 20, the measure of likelihood being a probability.

23. The system of claim 20, the determining the statistical measures of the spatial distribution of the reference points including estimating an area of a smallest geometric figure that encompasses estimated geographic locations associated with the reference points.

24. The system of claim 20, further comprising:

each reference point being associated with a reliability value that corresponds to a relative measure of an accuracy of an estimate of a geographic position of the reference point; and

the determining the set of one or more reference points associated with the designated wireless device comprising including within the set only those reference points having a reliability value that is above a threshold value.

25. The system of claim 20, the determining a measure of likelihood that the designated wireless device exhibits signal transmission range that is atypical of a wireless device of the type matching the designated wireless device being further based on an empirical measure of a signal transmission range of a wireless device of the type matching the designated wireless device.

26. The system of claim 20, the determining statistical measures of the spatial distribution of the reference points of the set including determining an estimated distance between the designated wireless device and at least one reference point of the set.

27. The system of claim 26, the determining the measure of likelihood that the designated wireless device exhibits signal transmission range that is atypical of a wireless device of the type matching the designated wireless device being based on a comparison between (i) the distances between the designated wireless device and the reference points of the set and (ii) an empirical measure of a signal transmission range of a wireless device of the type matching the designated wireless device.

28. The system of claim 26, further comprising:

for reference points that are another wireless devices, each of the another wireless devices being associated with a measure of likelihood that the another wireless device of the set exhibits signal transmission range that is atypical of a wireless device of the type matching the another wireless device; and

the determining a set of one or more reference points associated with the designated wireless device comprising including within the set only those another wireless devices having an associated measure of likelihood that the another wireless device exhibits signal transmission range that is atypical of a wireless device of the type matching the another wireless device that is below a threshold value.

29. The system of claim 26, the determining the estimated distances between the designated wireless device and the at least one reference point of the set being based on a geographic location associated with the at least one reference point, and being further based on received signal strength values associated with the signals as detected at the geographic location.

30. The system of claim 26, the designated wireless device being a WiFi-enabled access point.

31. The system of claim 26, the designated wireless device being a mobile telephone transceiver installation.

32. The system of claim 20, the determining statistical measures of the spatial distribution of the reference points of the set including determining a plurality of estimated distances between the designated wireless device and a corresponding plurality of reference points of the set and determining a first distance among the plurality of estimated distances that corresponds to a selected percentile.

33. The system of claim 32, the determining the measure of likelihood that the designated wireless device is exhibiting signal transmission range that is atypical of a wireless device of the type matching the designated wireless device being based on a comparison between (i) the first distance corresponding to the selected percentile and (ii) an empirical measure of a signal transmission range of a wireless device of the type matching the designated wireless device.

34. The system of claim 20, the designated wireless device having a first identifier and the computer readable media further including instructions that when executed by a computer system cause the computer system to determine a second measure of likelihood that a second designated wireless device exhibits signal transmission range that is atypical of a wireless device of a type matching the second designated wireless device based on a comparison of the first identifier and a second identifier associated with the second designated wireless device.

35. The system of claim 20, the designated wireless device having an identifier and the computer readable media further including instructions that when executed by a computer system cause the computer system to associate, in a reference database, the identifier with an indication of the measure of likelihood.

36. The system of claim 20, the designated wireless device being a WiFi-enabled access point.

37. The system of claim 20, the designated wireless device being a mobile telephone transceiver installation.

38. The system of claim 20, for reference points of the set that are another wireless device, the another wireless device of the set being at least one of a WiFi-enabled access point and a mobile telephone transceiver installation.