Patent ID: 7890120

Claim:
A method of locating a cellular terminal comprising the steps of: detecting a handover event of the cellular terminal from a first network signal transmission region to a second network signal transmission region; transmitting to a database from the cellular terminal at least one network signal transmission region identifier associated with the handover event; determining whether the handover event exists in the database; extracting from the database a location of the handover event if the handover event exists in the database; determining whether a reverse handover event of the cellular terminal from the second network signal transmission region to the first network signal transmission region exists in the database; extracting the location of the reverse handover event from the database to determine the location of the cellular terminal if the reverse handover event exists in the database; determining a location of the first network signal transmission region and the second network signal transmission region to determine the location of the cellular terminal if the reverse handover event does not exist in the database; extracting information relating to at least one of location and geometry of the first and second network signal transmission regions based on transmitting a request from the database to a network provider for information corresponding to at least one of the first and second network signal transmission regions; calculating a handover region between the first and second network signal transmission regions and the centre of the handover region based on the at least one of location and geometry information so as to provide an estimate of the location of the handover event; and expanding an area of the handover region by an amount based on comparing a signal power before and after the handover event with hose obtained in connection with earlier handover events recorded on the database between the first and second network signal transmission regions so as to compensate for effects of shadowing within at least one of the first and second identified regions.