A method and system for estimating the location of a mobile device. A range of the mobile device to a reference station may be determined as a function of the time of transmission of a first signal transmitted from a base station and as a function of the time of receipt of a second signal transmitted from the mobile device to the reference station, the second signal being a function of the first signal advanced by a timing parameter. A relationship for each of a plurality of grid points in a geographic region may be determined as a function of the determined range and a range metric. These plural grid points may contain the reference station. The determined relationship may be compared with data corresponding to each of the plural grid points, and a location of the mobile device determined as a function of the comparison.