Calculation of quality of WLAN access point characterization for use in a WLAN positioning system

Patent metadata

Field	Value
Publication number	US-9363785-B2
Application number	US-40466409-A
Country	US
Kind code	B2
Filing date	Mar 16, 2009
Priority date	May 8, 2006
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

Methods and systems for classifying WLAN access points according to the quality of estimation of characteristics of the WLAN access points are provided. The classifications may be used to scale a reference database and quantify an expected error of estimation of the characteristics of the access points. WLAN access points may be classified based on their impact on a user's position, speed of travel, and direction of travel estimation accuracy in a WLAN positioning system. A method for determining a quality of estimation of characteristics of a Wi-Fi access point comprises a Wi-Fi enabled scanning device measuring a number of received signal strength (RSS) samples of the Wi-Fi signal transmitted by the Wi-Fi access point. A total distance traveled by the Wi-Fi enabled scanning device while measuring the number of RSS samples is estimated and used to estimate the quality of estimation of characteristics of the Wi-Fi access point.

First claim

What is claimed is:

1. A method of estimating a position of a wireless local area network (WLAN) enabled device, the method comprising:
receiving identities of WLAN access points within range of the WLAN enabled device;
retrieving, by software of a WLAN positioning system executing on a computing device, one or more estimated characteristics and a quality metric of each of at least one of the identified WLAN access points from a reference database, wherein the estimated characteristics include a calculated location of a corresponding WLAN access point, and the quality metric of the corresponding WLAN access point is a measure of how accurately the estimated characteristics, including the calculated location, of the corresponding WLAN access point have been estimated; and
estimating, by the software of the WLAN positioning system executing on the computing device or another computing device, the position of the WLAN enabled device, wherein
the calculated location of each of the at least one of the identified WLAN access points is weighted when used in the estimating the position of the WLAN enabled device with a weight assigned to each calculated location determined based on the quality metric corresponding to the identified WLAN access point, or
the calculated location of each of the at least one of the identified WLAN access points is excluded from use in the estimating the position of the WLAN enabled device based on the quality metric of the identified WLAN access point when the quality metric corresponding to the identified WLAN access point is below a threshold.

2. The method of claim 1 , wherein the estimated characteristics further include radio propagation characteristics of the corresponding WLAN access point.

3. The method of claim 1 , wherein the quality metric is based on a number of received signal strength (RSS) samples of a wireless signal transmitted by the corresponding WLAN access point.

4. The method of claim 1 , wherein the at least one quality metric is based on an accuracy of estimated locations where received signal strength (RSS) samples of a wireless signal transmitted by the corresponding WLAN access point were collected.

5. A method of estimating a position of a wireless local area network (WLAN) enabled device, the method comprising:
receiving, by software of a WLAN positioning system executing on a computing device, identities of WLAN access points within range of the WLAN enabled device;
retrieving, by the software of a WLAN positioning system executing on a computing device, one or more estimated characteristics and a quality metric corresponding to each of at least one of the identified WLAN access points from a reference database, wherein the estimated characteristics include a calculated location of a corresponding WLAN access point, the quality metric is based on a number of received signal strength (RSS) samples of a wireless signal transmitted by the corresponding WLAN access point, and the RSS samples are weighted according to an estimated speed of one or more scanning devices that collected the RSS samples, the weighting to cause RSS samples collected by a scanning device while moving at a higher speed to produce a higher quality metric than RSS samples collected by a scanning device while moving at a lower speed; and
estimating, by the software of the WLAN positioning system executing on the computing device or another computing device, the position of the WLAN enabled device based on the calculated location and the quality metric of the at least one of the identified WLAN access points.

6. A non-transitory electronic device readable media having software stored thereon, the software when executed operable to:
determine identities of a plurality of wireless local area network (WLAN) access points within a range of a WLAN enabled device;
retrieve, from a reference database, a calculated location and a quality metric corresponding to each of at least one of the plurality of WLAN access points, wherein the quality metric of a corresponding WLAN access point indicates accuracy of the calculated location of the corresponding WLAN access point, and the quality metric is based at least in part on a number of samples of a wireless signal transmitted by the corresponding WLAN access point; and
estimate the position of the WLAN enabled device based on the calculated location and the quality metric of each of the at least one of the WLAN access points, wherein a WLAN access point's effect on the estimated position is weighted according to the WLAN access point's corresponding quality metric such that WLAN access points having higher quality metrics are given more weight than WLAN access points having lower quality metrics.

7. The non-transitory electronic device of claim 6 , wherein the samples are received signal strength (RSS) samples.

8. The non-transitory electronic device readable media of claim 6 , wherein the samples are weighted according to an estimated speed of one or more scanning devices that collected the samples, the weighting to cause samples collected by the one or more scanning devices while moving at a higher speed to produce a higher quality metric than samples collected by the one or more scanning devices while moving at a lower speed.

9. The non-transitory electronic device readable media of claim 6 , wherein the quality metric is based at least in part on an accuracy of estimated locations where samples were collected.

10. A method of estimating a position of a wireless local area network (WLAN) enabled device, the method comprising:
determining identities of a plurality of wireless local area network (WLAN) access points within a range of a WLAN enabled device;
retrieving, from a reference database by software of a WLAN positioning system executing on a computing device, a calculated location and a quality metric corresponding to each of at least one of the plurality of WLAN access points, wherein the quality metric of a corresponding WLAN access point indicates accuracy of the calculated location of the corresponding WLAN access point, and the quality metric is based at least in part on a number of samples of a wireless signal transmitted by the corresponding WLAN access point; and
estimating, by the software of the WLAN positioning system executing on the computing device or another computing device, the position of the WLAN enabled device based on the calculated location and the quality metric of each of the at least one of the WLAN access points, wherein WLAN access point's effect on the estimated position is weighted according to the WLAN access point's corresponding quality metric such that WLAN access points having higher quality metrics are given more weight than WLAN access points having lower quality metrics.

11. The method of claim 10 , wherein the samples are received signal strength (RSS) samples.

12. The method of claim 10 , wherein the samples are weighted according to an estimated speed of one or more scanning devices that collected the samples, the weighting to cause samples collected by the one or more scanning devices while moving at a higher speed to produce a higher quality metric than samples collected by the one or more scanning devices while moving at a lower speed.

13. The method of claim 10 , wherein the quality metric is based at least in part on an accuracy of estimated locations where samples were collected.

Assignees

• Alizadeh-Shabdiz Farshid
• Pahlavan Kaveh
• Brachet Nicolas
• Skyhook Wireless Inc

Inventors

• Alizadeh-Shabdiz Farshid
• Pahlavan Kaveh
• Brachet Nicolas

Classifications

• H04W84/12

  WLAN [Wireless Local Area Networks] · CPC title

• H04W64/00

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

• H04W48/20

  Selecting an access point · CPC title

• H04W48/16

  Discovering, processing access restriction or access information · CPC title

• H04W64/006 Primary

  with additional information processing, e.g. for direction or speed determination · CPC title