System and method for estimating positioning error within a WLAN-based positioning system
In one embodiment, a technique is provided for estimating and using an expected error of a position estimate of a WLAN-enabled mobile device produced by a WLAN positioning system. The WLAN-enabled mobile device receives signals transmitted by a plurality of WLAN access points in range of the WLAN-enabled device. The position of the WLAN-enabled device is estimated based on the received signals from the WLAN access points in range of the WLAN-enabled device. An expected error of the position estimate is based on at least one of a spatial spread associated with geographic positions of the WLAN access points, signal coverage areas of the WLAN access points, or a number of the WLAN access points. The expected error is used in providing one or more location-based services to a user of the WLAN-enabled mobile device.
1. A method of estimating and using an expected error of a position estimate of a wireless local area network (WLAN)-enabled mobile device produced by a WLAN positioning system, the method comprising:
receiving, by the WLAN-enabled mobile device, signals transmitted by a plurality of WLAN access points in range of the WLAN-enabled device;
estimating the position of the WLAN-enabled device based on the received signals from the WLAN access points in range of the WLAN-enabled device;
estimating an expected error of the position estimate based on at least one of a spatial spread associated with geographic positions of the WLAN access points or a number of the WLAN access points; and
using the expected error in providing one or more location-based services to a user of the WLAN-enabled mobile device.
2. The method of claim 1 , wherein the expected error is represented in terms of distance.
3. The method of claim 1 , wherein the expected error is based on the spatial spread associated with geographic positions of the WLAN access points.
4. The method of claim 3 , wherein the expected error is directly proportional to a square of a standard deviation of the spatial spread of the geographic positions of the WLAN access points.
5. The method of claim 1 , wherein the expected error is based on the number of the WLAN access points.
6. The method of claim 5 , wherein the expected error is inversely proportional to the square root of the number of WLAN access points.
7. The method of claim 1 wherein the using the expected error comprises:
excluding the position estimate of the WLAN-enabled mobile device from a combination of position estimates used to produce a position of WLAN-enabled mobile device to be used in the one or more location-based services.
8. The method of claim 1 , wherein the using the expected error comprises:
weighting the position estimate of the WLAN-enabled mobile device in a combination of position estimates used to produce a position of WLAN-enabled mobile device to be used in the one or more location-based services.
9. A method of estimating and using an expected error of a position estimate of a wireless local area network (WLAN)-enabled mobile device produced by a WLAN positioning system, the method comprising:
receiving, by the WLAN-enabled mobile device, signals transmitted by a plurality of WLAN access points in range of the WLAN-enabled device;
estimating the position of the WLAN-enabled device based on the received signals from the WLAN access points in range of the WLAN-enabled device;
estimating an expected error of the position estimate based on based on a smallest signal coverage area of a WLAN access point of the WLAN access points
using the expected error in providing one or more location-based services to a user of the WLAN-enabled mobile device.
10. The method of claim 9 , wherein the expected error is directly proportional to the smallest signal coverage area.
11. A system for estimating and using an expected error of a position estimate of a wireless local area network (WLAN)-enabled mobile device, the system comprising:
a WLAN-enabled mobile device configured to receive signals transmitted by a plurality of WLAN access points in range of the WLAN-enabled mobile device;
positioning software residing on the WLAN-enabled mobile device, the positioning software when executed operable to:
estimate the position of the WLAN-enabled device based on the received signals from the WLAN access points in range of the WLAN-enabled device;
estimate an expected error of the position estimate based on at least one of a spatial spread associated with geographic positions of the WLAN access points or a number of the WLAN access points; and
use the expected error in in determining a position used in one or more location-based services provided to a user of the WLAN-enabled mobile device.
12. The system of claim 11 , wherein the expected error is represented in terms of distance.
13. The system of claim 11 , wherein the expected error is based on the spatial spread associated with geographic positions of the WLAN access points.
14. The system of claim 11 , wherein the expected error is based on the number of the WLAN access points.
15. A non-transitory device-readable medium with software stored thereon that when executed on a wireless local area network (WLAN)-enabled device is operable to:
estimate the position of the WLAN-enabled device based on received signals from WLAN access points in range of the WLAN-enabled device;
estimate an expected error of the position estimate based on at least one of a spatial spread associated with geographic positions of the WLAN access points or a number of the WLAN access points; and
using the expected error in providing one or more location-based services to a user of the WLAN-enabled mobile device.
16. The non-transitory device-readable medium of claim 15 , wherein the expected error is based on the spatial spread associated with geographic positions of the WLAN access points.
17. The non-transitory device-readable medium of claim 15 , wherein the expected error is based on the number of the WLAN access points.
18. A method of estimating and using an expected error of a position estimate of a wireless local area network (WLAN)-enabled mobile device produced by a WLAN positioning system, the method comprising:
receiving, by the WLAN-enabled mobile device, signals transmitted by a plurality of WLAN access points in range of the WLAN-enabled device;
estimating the position of the WLAN-enabled device based on the received signals from the WLAN access points in range of the WLAN-enabled device;
estimating an expected error of the position estimate based on a spatial spread associated with geographic positions of the WLAN access points, wherein the spatial spread is a measure of distances between the estimated geographic locations of the WLAN access points;
using the expected error in providing one or more location-based services to a user of the WLAN-enabled mobile device.
19. The method of claim 18 , wherein the expected error is directly proportional to a square of a standard deviation.
20. A method of estimating and using an expected error of a position estimate of a wireless local area network (WLAN)-enabled mobile device produced by a WLAN positioning system, the method comprising:
receiving, by the WLAN-enabled mobile device, signals transmitted by a plurality of WLAN access points in range of the WLAN-enabled device;
estimating the position of the WLAN-enabled device based on the received signals from the WLAN access points in range of the WLAN-enabled device;
estimating an expected error of the position estimate based on a number of the WLAN access points, wherein the expected error of the position decreases as the number of detected access points increases; and
using the expected error in providing one or more location-based services to a user of the WLAN-enabled mobile device.
21. The method of claim 20 , wherein the expected error is inversely proportional to the square root of the number of WLAN access points.