| 摘要 |
PURPOSE:To display the current position of a vehicle properly on a road by arranging a displacement angle detection means, an earth magnetism detection means, an ongoing azimuth calculating means, first and second current position calculating means, a comparison means, a road retrieving means and the like. CONSTITUTION:A CPU 11 calculates a displacement angle of a vehicle from an angular velocity information of the vehicle to be obtained from an angular velocity detector 3 and a ongoing direction of the vehicle is calculated from the displacement angle and azimuth information from an earth magnetism sensor 5. An estimated current position of the vehicle is calculated based on a signal azimuth of the vehicle and moving distance information thereof detected with a distance detector 1. On the other hand, the CPU 11 inputs a signal received from a GPS satellite which performs a receiving with a GPS receiver 7 to calculate the current position of the vehicle. The GPS current position is compared with the estimated current position and when the estimated current position is not separated by more than a specified distance from the GPS current position, the estimated current position is determined as the current position. When it is separated by more than the specified distance, the GPS current position is determined as current position. Thus, a road where the vehicle exists is searched from the current position and the azimuth of the vehicle to be shown on a display 13 being interposed with the position of the vehicle on the road. |
