METHOD AND SYSTEM FOR DETERMINING LOCATION USING A HYBRID SATELLITE AND WLAN POSITIONING SYSTEM BY SELECTING THE BEST WLAN-PS SOLUTION
This disclosure describes a method and system for determining location using a hybrid satellite and WLAN positioning system by selecting the best WLAN-PS solution. In some embodiments, the method of increasing the accuracy of a WLAN based position estimate using satellite positioning information can include determining a set of possible WLAN location solutions for a WLAN and satellite enabled device based on one or more WLAN access points, obtaining satellite information for the WLAN and satellite enabled device from at least two different satellites, and using the satellite information from the at least two different satellites to determine the best WLAN location solution from the set of possible WLAN location solutions.
1 . A method of increasing the accuracy of a WLAN based position estimate using satellite positioning information, the method comprising:
determining a set of possible WLAN location solutions for a WLAN and satellite enabled device based on one or more WLAN access points;
obtaining satellite information for the WLAN and satellite enabled device from at least two different satellites; and
using the satellite information from the at least two different satellites to determine the best WLAN location solution from the set of possible WLAN location solutions.
2 . The method of claim 1 , wherein using the satellite information from the at least two different satellites to determine the best WLAN location solution from the set of possible WLAN location solutions comprises:
examining each of the possible WLAN location solutions against the satellite information; and
selecting the location of the WLAN and satellite enabled device based on which of the possible WLAN location solutions satisfies the satellite information.
3 . The method of claim 1 , wherein the step of using the satellite information from the at least two different satellites to determine the best WLAN location solution from the set of possible WLAN location solutions comprises:
eliminating possible WLAN location solutions which are not consistent with the satellite information.
4 . The method of claim 3 , wherein the WLAN location solution consistency with the satellite information is measured by applying each of the possible WLAN location solutions to the satellite measurements and calculating the internal SPS receiver clock bias for each possible WLAN location solutions.
5 . The method of claim 4 , wherein the consistency of the internal SPS receiver clock for each of the possible WLAN location solutions is used as an indication of distance between the WLAN location solutions and possible solutions of satellite positioning system.
6 . The method of claim 4 , wherein the consistency of the internal SPS receiver clock for each of the possible WLAN location solutions is used as an indication of consistency between the WLAN location solutions and the satellite measurements.
7 . The method of claim 4 , wherein substantially the same internal SPS receiver clock bias across the acquired satellites for a given WLAN location solution indicates a good location estimate.
8 . The method of claim 4 , wherein non-uniform values of internal SPS receiver clock bias across the acquired satellites for a given WLAN location solution indicates a poor location estimate.
9 . The method of claim 1 , wherein the set of possible WLAN location solutions comprises a cluster.
10 . The method of claim 1 , wherein the satellite information provides a satellite location solution in the form of a region, a surface, or a curve.
11 . The method of claim 10 comprising weighing the WLAN location solutions according to the distance from each WLAN location solution to the satellite location solution.
12 . The method of claim 11 comprising selecting WLAN location solutions having a small distance to the satellite location solution.
13 . The method of claim 12 , wherein the small distance is on the order of ten meters.
14 . The method of claim 13 comprising eliminating WLAN location solutions having a large distance to the satellite location solution.
15 . The method of claim 14 , wherein the large distance is on the order of one thousand meters.
16 . The method of claim 1 , wherein the satellite information comprises satellite position data, satellite velocity data, psuedorange measurement, Doppler frequency measurement, and time of signal transmission.
17 . A system for increasing the accuracy of a WLAN based position estimate using satellite positioning information, the system comprising:
a positioning module comprising:
a WLAN module for receiving information from one or more WLAN access points;
a satellite positioning module for obtaining satellite information from at least two different satellites;
logic located in the WLAN module to determine a set of possible WLAN location solutions based on one or more WLAN access points; and
logic located in the positioning module to use the satellite information from the at least two different satellites to determine the best WLAN location solution from the set of possible WLAN location solutions.
18 . The system of claim 17 , wherein the logic located in the positioning module to use the satellite information from the at least two different satellites to determine the best WLAN location solution from the set of possible WLAN location solutions further comprises logic to examine each of the possible WLAN location solutions against the satellite information and select the location of the WLAN and satellite enabled device based on which of the possible WLAN location solutions satisfies the satellite information.
19 . The system of claim 18 , wherein the WLAN location solution consistency with the satellite information is measured by applying each of the possible WLAN location solutions to the satellite measurements and calculating an internal SPS receiver clock bias for each possible WLAN location solutions.
20 . The system of claim 19 , wherein the consistency of the internal SPS receiver clock for each of the possible WLAN location solutions is used as an indication of distance between the WLAN location solutions and possible solutions of satellite positioning system.
21 . The system of claim 19 , wherein the consistency of the internal SPS receiver clock for each of the possible WLAN location solutions is used as an indication of consistency between the WLAN location solutions and the satellite measurements.
22 . The system of claim 19 , wherein substantially the same internal SPS receiver clock bias across the acquired satellites for a given WLAN location solution indicates a good location estimate.
23 . The system of claim 19 , wherein non-uniform values of internal SPS receiver clock bias across the acquired satellites for a given WLAN location solution indicates a poor location estimate.
24 . The system of claim 17 , wherein the satellite information comprises satellite position data, satellite velocity data, psuedorange measurement, Doppler frequency measurement, and time of signal transmission.
25 . The system of claim 17 , wherein the set of possible WLAN location solutions comprises a cluster.
26 . The method of claim 17 , wherein the satellite information provides a satellite location solution in the form of a region, a surface, or a curve.
27 . The method of claim 26 , further comprising weighing the WLAN location solutions according to the distance from each WLAN location solution to the satellite location solution.
28 . The method of claim 27 , further comprising selecting WLAN location solutions having a small distance to the satellite location solution.
29 . The method of claim 28 , wherein the small distance is on the order of ten meters.
30 . The method of claim 27 comprising eliminating WLAN location solutions having a large distance to the satellite location solution.
31 . The method of claim 30 , wherein the large distance is on the order of one hundred meters.
32 . A mobile device having a hybrid positioning system for increasing the accuracy of a WLAN based position estimate using satellite positioning information, the mobile device comprising:
a hybrid positioning module comprising:
a WLAN module for receiving information from one or more WLAN access points;
a satellite positioning module for obtaining satellite information from at least two different satellites;
logic located in the WLAN module to determine a set of possible WLAN location solutions based on one or more WLAN access points; and
logic located in the positioning module to use the satellite information from the at least two different satellites to determine the best WLAN location solution from the set of possible WLAN location solutions.