Reliable location information for a mobile station using a non-GPS location technique
A method and apparatus determines if a location fix received by a mobile station using a non-GPS location techniques is accurate. Location results obtained using the non-GPS location technique or techniques are treated as accurate if they are verified as being within an error margin obtained from a trusted source of location information such as a GPS positioning system. Non-GPS Location information may be obtained from a signal transmitted by the base station, which signal includes the base station location. The non-GPS location information may also be obtained from a backend service associated with the wireless network that includes the base station.
1. A method by which a mobile station confirms its location, comprising:
obtaining a first location fix of a mobile station from a beacon received from a base station;
forwarding the first location fix to a backend server associated with the base station;
receiving a second location fix from the backend server;
comparing the first location fix obtained from the beacon to the second location fix obtained from the backend server associated with the base station; and
validating the first location fix if it matches the second location fix within an initial error margin having a maximum value defined by a maximum coverage area of the base station,
wherein the error margin is reduced to a value derived from a trusted source of location information, when the value derived from the trusted source of location is less than the maximum value defined by the coverage area of the base station.
2. The method of claim 1 wherein, if the first location fix is verified, further comprising communicating the first location fix to an application requesting a location fix of the mobile station, said application being associated with the mobile station.
3. The method of claim 2 wherein the application resides on the mobile station.
4. The method of claim 2 wherein the application implements a location-based service.
5. The method of claim 1 wherein the trusted source is a GPS system that determines the error margin for the base station from a plurality of mobile stations that detect a signal from the base station.
6. The method of claim 1 wherein obtaining the first location fix includes retrieving the first location fix from a local cache in the mobile station where the first location fix was previously stored in association with a base station identifier obtained from the beacon.
7. The method of claim 1 further comprising storing the first location fix in a local cache of the mobile station after it has been verified.