Patent ID: 7138946

Claim:
A method for determining a position of a terminal in a system having a terminal apparatus, a plurality of base stations in communication with the terminal apparatus, and a server apparatus connected to the plurality of base stations via a network, the method comprising: detecting via the server apparatus a position of the terminal apparatus through at least either a first position detection process or a second position detection process; performing a first position detection process, including receiving at others of the plurality of base stations signals transferred between one of the plurality of base stations and the terminal apparatus, collecting at the server apparatus information about reception timings of the signals received at each of the others of the plurality base stations, and calculating a position of the terminal apparatus using a plurality of the reception timings and position information about the others of the plurality of base stations; performing a second position detection process, including collecting at the server apparatus measurement information about received powers of signals transferred between the terminal apparatus and the others of the plurality of base stations, and searching a received power measurement information database previously stored in the server apparatus using a plurality of the measurement information about the received powers, and determining a position of the terminal apparatus based on the searching; storing, in the received power measurement information database, the position information and received power measurement information corresponding to the position information, the position information being obtained by at least one of the first position detection process and the second position detection process, and the received power measurement information being the received powers of the signals corresponding to the plurality of base stations in response to that the terminal apparatus is detected to be at the position indicated by said position information; and determining via the server apparatus whether to execute the second position detection process according to information stored in the received power measurement information database.