| 摘要 |
PURPOSE:To perform accurate detection which is free of an error in cumulation by identifying the area of a current position based on the variation in the frequency of a carrier received by an automobile telephone terminal device and determining a moving direction based on the history of the run area. CONSTITUTION:Carriers of different frequency sent out of fixed stations A2, B2, C2, and D2 arranged in geographic areas A1, B1, C1, and D1 are propagated to areas A3, B3, C3, and D3. When a moving body receives carriers from the station C2 firstly and then from the station B2, it is identified that the body moves from the area C1 to the area B1 and its moving direction is as shown by an arrow. A navigation controller 3 decides the moving direction based on the variation in the frequency of a carrier detected by an automobile telephone terminal device 2 which has an FM communication with a radio station 9 and an engine controller 5 performs calculation based on the signal of a vehicle speed sensor 12 to find the current position from a vehicle speed inputted through a serial data link 6; and a controller 4 displays the current position on a display 11. |
