Estimation of position using WLAN access point radio propagation characteristics in a WLAN positioning system
First Claim
1. A method of characterizing at least one of Wi-Fi access points, using the coverage area of the Wi-Fi access point, so that the characterization may be used later to effectively weigh signals transmitted by said Wi-Fi access point when performing a location estimation, the method of characterization comprising:
- determining the geographic location of the Wi-Fi access points;
for each Wi-Fi access point, measuring a plurality of power values for signals transmitted by a corresponding Wi-Fi access point, each power value being measured at position relative to each corresponding Wi-Fi access point;
determining a signal coverage area of each Wi-Fi access point based on said measured plurality of power values;
dividing the signal coverage area of the Wi-Fi access point into at least two sections,Wherein the coverage area is divided according to at least two radials and at least one distance from the Wi-Fi access point;
determining radio propagation characteristics for each section; and
assigning a weight to each section based on the coverage areas of the Wi-Fi access points, where sections having relatively small coverage areas are assigned a higher effective weight than sections having relatively large coverage areas,wherein the location estimation will bias its estimate of position to rely on signals detected from the Wi-Fi access points with relatively smaller coverage areas, even if said signals are detected with relatively weaker power than signals detected from Wi-Fi access points with larger coverage areas and relatively higher power.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for estimating position using WLAN access point radio propagation characteristics in a WLAN location based service is provided. A location-based services system has a plurality of Wi-Fi access points in a target area. The Wi-Fi access points are positioned at geographic locations and have signal coverage areas. A method of characterizing at least one of the Wi-Fi access points comprises determining the geographic location of the Wi-Fi access point, dividing the signal coverage area of the Wi-Fi access point into at least one section, and determining radio propagation characteristics for each section. The radio propagation characteristics of each section characterize a radio channel of the Wi-Fi access point, and the characterization can be used in a location algorithm.
-
Citations
20 Claims
-
1. A method of characterizing at least one of Wi-Fi access points, using the coverage area of the Wi-Fi access point, so that the characterization may be used later to effectively weigh signals transmitted by said Wi-Fi access point when performing a location estimation, the method of characterization comprising:
-
determining the geographic location of the Wi-Fi access points;
for each Wi-Fi access point, measuring a plurality of power values for signals transmitted by a corresponding Wi-Fi access point, each power value being measured at position relative to each corresponding Wi-Fi access point;determining a signal coverage area of each Wi-Fi access point based on said measured plurality of power values; dividing the signal coverage area of the Wi-Fi access point into at least two sections, Wherein the coverage area is divided according to at least two radials and at least one distance from the Wi-Fi access point; determining radio propagation characteristics for each section; and
assigning a weight to each section based on the coverage areas of the Wi-Fi access points, where sections having relatively small coverage areas are assigned a higher effective weight than sections having relatively large coverage areas,wherein the location estimation will bias its estimate of position to rely on signals detected from the Wi-Fi access points with relatively smaller coverage areas, even if said signals are detected with relatively weaker power than signals detected from Wi-Fi access points with larger coverage areas and relatively higher power. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method for estimating the position of a Wi-Fi enabled device using qualitative data related to one or more characteristics of a Wi-Fi access point'"'"'s signal coverage area, the method comprising:
-
receiving one or more signals transmitted by the Wi-Fi access points; identifying the Wi-Fi access points; retrieving previously calculated locations of the Wi-Fi access points and previously calculated weights assigned to the Wi-Fi access points from a reference database, where the weights correspond to characteristics of each Wi-Fi access point'"'"'s coverage area, including a plurality of measured power values for each access point, wherein the coverage is divided according to at least two radials and at least one distance from the Wi-Fi access point and using the calculated locations and the calculated weights to estimate the position of the Wi-Fi enabled device, wherein Wi-Fi access points having relatively small coverage areas are assigned a higher effective weight than Wi-Fi access points having relatively large coverage areas and the position estimate of the Wi-Fi enabled device will be biased to rely more heavily rely on signals detected from the Wi-Fi access points with relatively smaller coverage areas, even if said signals are detected with relatively weaker power than signals detected from Wi-Fi access points with larger coverage areas and relatively higher power. - View Dependent Claims (13)
-
-
14. A method of characterizing Wi-Fi access points in order to increase the accuracy of position, velocity and bearing estimation techniques based on signals received from those access points by classifying the Wi-Fi access points based on coverage areas of the Wi-Fi signals emitted by the Wi-Fi access points, the method of characterizing comprising:
-
measuring a series of Wi-Fi signals of each Wi-Fi access point; determining a coverage area of each Wi-Fi access point based on its corresponding series of signals;
wherein the coverage is divided according to at least two radials and at least one distance from the Wi-Fi access point; andassigning a weight to each Wi-Fi access point based on the coverage areas in which Wi-Fi access points having relatively small coverage areas are assigned a higher effective weight than Wi-Fi access points having relatively large coverage areas, wherein position, velocity, and bearing estimation techniques will bias their estimates of position, velocity, and bearing to more heavily rely on signals detected from the Wi-Fi access points with relatively smaller coverage areas, even if said signals are detected with relatively weaker power than signals detected from Wi-Fi access points with larger coverage areas and relatively higher power. - View Dependent Claims (15, 16, 17, 18, 19)
-
-
20. A method of characterizing Wi-Fi access points in order to increase the accuracy of position, velocity and bearing estimation techniques based on signals received from those access points by classifying the Wi-Fi access points based on coverage areas of the Wi-Fi signals emitted by the Wi-Fi access points, the method of characterizing comprising:
-
measuring a series of power values of the Wi-Fi signal of the Wi-Fi access point at a plurality of distances from the Wi-Fi access point; determining a coverage area of the Wi-Fi access point based on the series of power values at the plurality of distances; and assigning a weight to the Wi-Fi access point based on the coverage area, wherein the coverage is divided according to at least two radials and at least one distance from the Wi-Fi access point, wherein the weight of the Wi-Fi access point is assigned using the differential of the power in dB and the distance in dB from the Wi-Fi access point, wherein a larger differential corresponds to a higher weight and a smaller differential corresponds to a smaller weight, so that position, velocity, and bearing estimation techniques will bias their estimates position, velocity, and bearing to move heavily rely on signals detected from the Wi-Fi access points with a relatively larger differential.
-
Specification