| 摘要 |
PROBLEM TO BE SOLVED: To perform position detection without receiving radio waves of a general-purpose earth position measurement system by comparing a receiving level map which associates information, corresponding to the receiving levels of radio waves from plural radio base stations with the identification codes of the radio base stations and the position of the mobile station and holds it, with a mobile station receiving level and the identification code of the radio base station, and detecting the position of the mobile station. SOLUTION: Receiving level map data is downloaded from a receiving level map database 500 to each mobile station via each base station, as necessary. Outdoor mobile stations 110 and 170 hold receiving level map data even a wide area that includes outdoor radio zones Z1 and Z4. When the station 110 is to detect a position, it compares respective receiving levels of surrounding base stations including a base station 210, and a base station identification code with receiving level map data so as to detect the position. As a result, it is possible to miniaturize and economize a mobile station without the need for providing the mobile station with a receiver for receiving a general-purpose earth position measurement system radio wave. |
