MOBILE TELEPHONE LOCATION PROCESS MAKING USE OF HANDOFF DATA

A system for determining the location of a mobile station based upon measurable mobile data values such as those provided by mobile-assisted handoff (MAHO) procedures. The mobile stations make signal strength measurements of nearby base stations and return that information to the serving base station. A timing advance necessary to synchronize the mobile may also be determined. The signal strength measurements and the timing advance data then provide information to map to an estimated vehicle location. Since the mobiles are assumed to measure signal strength discretely, there may be several consecutive positions along a road which return identical mobile data. The road is thus segmented into constant segements which are consecutively indexed, and an association is established between the associated mobile data vector and the index. The process for location of a mobile consists of first finding the road for the mobile unit, then finding the position along the road. The mobile vector is sequentially input into a look up table or neural networks (one for each road in the sector) until an output coordinate pair actually lies near the corresponding road. From that point on, the input vector provides an index to a constant region along the road, so the mobile is unambiguously located as to which road, and to which segment along the road it occupies.