| 摘要 |
PROBLEM TO BE SOLVED: To obtain an on-vehicle navigator by which the advance direction of a vehicle can be discriminated by a method wherein, when a reversing-signal supply line is not connected, the advance direction of the vehicle is judged on the basis of the detection output value of an accelerometer and on the basis of the judgment of a logic and, when the line is connected, the logic of a reversing signal is judged on the basis of the judgment of a logic. SOLUTION: An accelerometer 1 and the line as well as a line connecting terminal 29 are connected to an interface 6, and the connection of a reversing-signal line is detected by a connection detecting sensor 30. A switch is operated, and the output value of the accelerometer 1 is read out. When the output value >0, it is treated as a positive logic, and, when the output value <=0, it is treated as a negative logic. Then, whether the reversing-signal line is connected or not is detected by the connection detecting sensor 30. When it is not connected, the speed of a vehicle is found on the basis of the output value of the accelerometer 1. When the output value >0, the advance of the vehicle is judged, and, when the output value <=0, the retreat of the vehicle is judged. When the reversing-signal line is connected, the level of a reversing signal is read out. When the advance is judged on the basis of the speed of the vehicle, the level is treated as the positive logic. When the retreat is judged, the level is treated as the negative logic. Thereby, the advance direction of the vehicle can be discriminated irrespective of whether the reversing-signal line is connected or not. |
