| 摘要 |
PURPOSE: To reduce a span of time necessary for the calculation of a current position without entailing any damage to authenticity that a calculated current position is the actual current position of a vehicle by selecting the specified proposed point from some proposed points in freedom, and constituting it so as to retrieve a road as to the selected point. CONSTITUTION: An estimated direction of a vehicle is determined with an absolute direction calculated by an output value of an azimuthal sensor 12 and a direction variation to be outputted out of an angular velocity sensor 11. A pulse number to be outputted by a car speed sensor 13 is counted by a counter 26, seeking a traveling distance in multiplying a distance coefficient to this counted value. Each latitude-longitude travel of a vehicle is added to the position of a proposed point of the vehicle obtained by a process seeking the vehicle proposed point of the last time, thereby seeking a virtual current position. In regard to only the proposed point in freedom obtained by the process seeking the last vehicle proposed point, a retrieval proposed point selecting process for matching a road is carried out. Next, in regard to only the proposed point in a matching state, a road retrieving process is executed. |
