Database correlation method for GSM location

Abstract

Cellular location methods based on angle of arrival (AOA) or time difference (e.g. E-OTD) measurements assume line-of-sight propagation between base stations and the mobile station. This assumption is not valid in urban microcellular environments. We present a database correlation method (DCM) that can utilize any location-dependent signals available in cellular systems. This method works best in densely built urban areas. An application of DCM to GSM, using signal strength measurements, is described and trial results from urban and suburban environments are given. Comparison with AOA and E-OTD trials shows that DCM is a competitive alternative for GSM location in urban and suburban environments.