Ntt Docomo, Inc.

Susumu Ogata

Masatoshi Kimoto

Jin Hoshino

A radio communication system includes a delay time acquiring unit configured to acquire a delay time of a signal transmitted between the mobile terminaland the base station; a position information acquiring unit configured to acquire a position of the base station; a calculating unit configured to calculate a position of the mobile terminalon the basis of the delay time acquired by the delay time acquiring unit, and the position of the base stationacquired by the position information acquiring unit; and a providing unit configured to provide mobile station position information indicating the position of the mobile terminal. When a predetermined exception condition is not satisfied, the providing unit provides, as the mobile station position information, the position of the mobile terminalcalculated by the calculating unit. When the predetermined exception condition is satisfied, the providing unit provides, as the mobile station position information, the position of the base stationacquired by the position information acquiring unit, instead of using the position of the mobile terminalcalculated by the calculating unit.

Radio communication system and position information providing apparatus

A position of a mobile communication terminal in an environment where the terminal cannot communicate with a GPS is defined more narrowly than a sector area of a base station in which the mobile communication terminal is located so that the position of the mobile communication terminal can be estimated more accurately. Even if a mobile communication terminal is in an environment where the terminal cannot communicate with a GPS, the latitude and longitude of the center of a sector of the wireless base station in which the mobile communication terminal is located is obtained according to a predetermined calculation by a base station database device, and the obtained latitude and longitude is sent back as an estimated latitude and longitude of the mobile communication terminal to the mobile communication terminal via the wireless base station.

Position estimation system

A position determination system includes a mobile terminal configured to receive GPS information from a GPS; a base station device configured to measure a round trip time (RTT) from the mobile terminal; a base-station position table unit configured to store position information on the base station device; a cable-length table unit configured to store a cable length between the base station device and an antenna assembly provided to the base station device, the antenna assembly communicates with the mobile terminal; and a position determination device configured to determine the position of the mobile terminal on the basis of the round trip time measured by the base station device, the cable length obtained from the cable-length table unit, the position information on the base station obtained from the base-station position table unit, and the GPS information received from the mobile terminal.

Growing community of inventors

Yokohama, Japan

Susumu Ogata