Patent ID: 9173056
Filing Date: 2015-10-27
Classification: H04W

Abstract:
1. A system for determining the location of a mobile device in communication with one or more radio transmitters at known locations comprising: a mobile communications network; a plurality of network transceivers; and a location server; wherein the mobile communications network is in communication with a mobile device via the plurality of network transceivers; wherein the location server receives and responds to requests for location-based data pertaining to the mobile device; wherein the location server computes an initial estimate of a location of the mobile device using cell tower triangulation and calculates a plurality of expected reception profiles at each point in a geographic grid comprising points in a neighborhood of the initial estimated location by combining, for each geographic grid point, predicted reception at the geographic grid point with actual reception data obtained from stored radio frequency fingerprint data for a plurality of locations near the geographic grid point, the available stored radio frequency fingerprint data for each nearby location weighted based at least on a distance from the geographic grid point to a the respective nearby location; wherein predicted reception for each geographic grid point is based at least on a terrain type through which a signal must travel to arrive at the grid point from each network transceiver for which reception is being predicted and on network specific data; wherein actual reception characteristics for the mobile device are compared to the plurality of expected reception profiles for points in the geographic grid in order to determine a closest match using an error function and thereby to accurately determine a location of the mobile device.