Patent ID: 8041304

Claim:
An area estimation system comprising: a radio signal transmitting terminal configured to transmit a radio signal to a certain radio signal receiving terminal via a network, with a presence area of the radio signal transmitting terminal being unknown; a plurality of radio signal capturing terminals configured to capture the radio signal transmitted from the radio signal transmitting terminal, and to measure a radio signal reception level, with a presence area of the radio signal capturing terminals being known; a reception level receiving unit configured to receive, from each of the radio signal capturing terminals via the network, the measured radio signal reception level, a radio signal transmitting terminal ID for uniquely identifying the radio signal transmitting terminal, and a radio signal capturing terminal ID for uniquely identifying each of the plurality of the radio signal capturing terminals; a reception level storage unit configured to store the measured radio signal reception level, the radio signal transmitting terminal ID and the radio signal capturing terminal ID, which are received from each of the radio signal capturing terminals, in association with one another; and a presence area estimating unit configured to refer to the reception level storage unit and to estimate the presence area of the radio signal transmitting terminal, by using at least one presence area of at least one radio signal capturing terminal identified by at least one radio signal capturing terminal ID associated with a predetermined range of at least one radio signal reception level stored in the reception level storage unit, wherein the presence area estimating unit comprises: a presence area candidate estimating unit configured to refer to the reception level storage unit and to specify, as a presence area candidate of the radio signal transmitting terminal, the at least one presence area of the at least one radio signal capturing terminal identified by the at least one radio signal capturing terminal ID associated with the predetermined range of the at least one radio signal reception level; and a presence area candidate narrowing unit configured to estimate the presence area of the radio signal transmitting terminal, from the presence area candidate of the radio signal transmitting terminal, on the basis of a confidence factor calculated based on the at least one radio signal reception level.