System and method for resolving multiple location estimate conflicts in a WLAN-positioning system

Patent metadata

Field	Value
Publication number	US-9253605-B2
Application number	US-76077710-A
Country	US
Kind code	B2
Filing date	Apr 15, 2010
Priority date	Mar 24, 2010
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

Methods of and systems for resolving multiple location estimate conflicts in a WLAN-positioning system are provided. Disclosed are methods to quantify the probability that a particular location estimate of a mobile device made by a Wi-Fi based positioning system is correct to within an arbitrary accuracy. Implementations use observed access point cluster size, age information for access point location determination, and/or cumulative distribution functions that characterize the conditional probability that one or more access points detected by the mobile device have relocated within a specified time interval to make the probability determinations.

First claim

What is claimed is:

1. A method of estimating a likelihood of a Wi-Fi enabled device being located within an estimated geographical area determined by a positioning system, the method comprising:
identifying Wi-Fi access points in range of the Wi-Fi enabled device based on signals received by the Wi-Fi enabled device transmitted by the Wi-Fi access points;
consulting a reference database to determine for each of a plurality of the Wi-Fi access points for which signals were received a last-known estimated position of the Wi-Fi access point;
determining that at least a first set of the Wi-Fi access points for which signals were received have potentially moved from their corresponding last-known estimated positions based on the last-known estimated positions for at least a second set of Wi-Fi access points for which signals were received, each access point of the second set of Wi-Fi access points being different from each access point of the first set of Wi-Fi access points; and
estimating, based on the number of Wi-Fi access points of the first set and the number of Wi-Fi access points of the second set, the likelihood of the Wi-Fi enabled device being located within the estimated geographical area.

2. The method of claim 1 , further comprising:
estimating, based on the number of Wi-Fi access points of the first set and the number of Wi-Fi access points of the second set, a plurality of likelihoods of the Wi-Fi enabled device being located within a corresponding plurality of estimated geographical areas; and
displaying on a display device information based on the plurality of estimated likelihoods of the Wi-Fi enabled device being located within the corresponding plurality of estimated geographical areas.

3. The method of claim 1 , wherein each of the Wi-Fi access points of the first set has a last-known estimated position that is within a first predetermined distance from the last-known estimated positions of other Wi-Fi access points of the first set, and each of the Wi-Fi access points of the second set has a last-known estimated position that is within a second predetermined distance from the last-known estimated positions of the other Wi-Fi access points of the second set.

4. The method of claim 1 , wherein the number of Wi-Fi access points of the first set is less than the number of Wi-Fi access points of the second set.

5. The method of claim 1 , wherein estimating the likelihood of the Wi-Fi enabled device being located within the estimated geographical area is further based on information that characterizes the conditional probability that the Wi-Fi access points of the first set have moved from their corresponding last-known position, the conditional probability being based on the number of Wi-Fi access points of the first set and the number of Wi-Fi access points of the second set, and wherein the conditional probability relies on a determination that last-known positions of a first Wi-Fi access point and a second Wi-Fi access point from which signals were received are in conflict.

6. The method of claim 5 , wherein the determination that the last-known positions of the first Wi-Fi access point and the second Wi-Fi access point from which signals were received are in conflict is based on the last known positions of the first Wi-Fi access point and second Wi-Fi access point being separated by more than a threshold distance.

7. The method of claim 5 , further comprising determining the conditional probability that at least one of the Wi-Fi access points of the first set has moved from its corresponding last-known position.

8. The method of claim 7 , wherein the determining the information that characterizes the conditional probability that at least one of the Wi-Fi access points has moved from its corresponding last-known position comprises:
determining a first collection of Wi-Fi access points that moved from a first geographic area to a second geographic area;
determining a second collection of Wi-Fi access points in the second geographic area, each access point of the Wi-Fi access points of the second collection being different Wi-Fi access points than each access point of the Wi-Fi access points of the first collection; and
based on the number of Wi-Fi access points of the first collection and the number of access points of the second collection, determining information that characterizes the conditional probability that a Wi-Fi access point has moved from its last-known position based on the number of Wi-Fi access points of the first set and the number of Wi-Fi access points of the second set.

9. The method of claim 8 , further comprising:
determining a third collection of Wi-Fi access points, each Wi-Fi access point of the third collection having a corresponding actual position that permits radio signals transmitted from said Wi-Fi access points to be received by a device capable of receiving Wi-Fi radio signals; and
determining that each Wi-Fi access point of a subset of the Wi-Fi access points of the third collection has moved from its corresponding last-known position based on a comparison of the last-known positions corresponding to each of the Wi-Fi access points of the third collection;
the determining information that characterizes the conditional probability that a Wi-Fi access point has moved from its last-known position being further based on the number of Wi-Fi access points of the subset and the number of Wi-Fi access points of the third collection not included in the subset.

10. The method of claim 1 , further comprising:
consulting the reference database to determine for at least a first Wi-Fi access point from which signals were received a last-known estimated position of the first Wi-Fi access point and time information associated with the last-known position for describing the age of the last-known position relative to other information in the reference database; and
the estimating the likelihood of the Wi-Fi enabled device being located within an estimated geographical area being further based on the last-known position and associated time information of the first Wi-Fi access point.

11. The method of claim 10 , wherein the estimating the likelihood of the Wi-Fi enabled device being located within the estimated geographical area is further based on information that characterizes the conditional probability that a Wi-Fi access point has moved from its corresponding last-known position, the conditional probability being based on the relative age of said last-known position, and wherein the conditional probability relies on a determination that last-known positions of a first Wi-Fi access point and a second Wi-Fi access point from which signals were received are in conflict.

12. The method of claim 11 , wherein the determination that the last-known positions of the first Wi-Fi access point and the second Wi-Fi access point from which signals were received are in conflict is based on the last known positions of the first Wi-Fi access point and second Wi-Fi access point being separated by more than a threshold distance.

13. The method of claim 11 , further comprising determining the information that characterizes the conditional probability that a Wi-Fi access point has moved from its corresponding last-known position.

14. The method of claim 13 , wherein the determining the information that characterizes the conditional probability that a Wi-Fi access point has moved from its corresponding last-known position based on the relative age of said last-known position comprises:
determining a set of Wi-Fi access points, each Wi-Fi access point of the set located at a first geographic position for the correspondi

Assignees

• Alizadeh-Shabdiz Farshid
• Ignatyev Oleksiy
• Skyhook Wireless Inc

Inventors

• Alizadeh-Shabdiz Farshid
• Ignatyev Oleksiy

Classifications

• G01S5/0242

  Determining the position of transmitters to be subsequently used in positioning (G01S5/0289 takes precedence) · CPC title

• H04W4/028 Primary

  Electricity · mapped topic

• H04W64/00

  Locating users or terminals {or network equipment} for network management purposes, e.g. mobility management · CPC title

• G01S5/0278

  involving statistical or probabilistic considerations (G01S5/0252, G01S5/0294 take precedence) · CPC title

• H04W24/10

  Scheduling measurement reports {; Arrangements for measurement reports} · CPC title