| 摘要 |
PURPOSE:To display the current position of a vehicle in a display element and thereby to know an exact position by having a map matching computation means which detects the position of the vehicle and a computation means which determines the coordinates of the position on the basis of information from a GPS satellite reception means and by comparing positional data obtained from the two computation means with each other by a comparing means. CONSTITUTION:When reception from a GPS satellite is impossible and map data are absent, the position of a vehicle is assumed by a dead-reckoning means 1. When the map data are absent while the reception from the GPS satellite is possible, the current position is modified to a position indicated by the GPS satellite, and when a plurality of spots are indicated thereby, it is modified to an average position. When the reception from the GPS satellite is possible and also the map data are present, moreover, the position determined from computation of information from the GPS satellite and a distance obtained by a map matching navigation are computed with respect to a plurality of positions obtained by the two means, and the position of the vehicle is modified to a position at which a difference between the positions obtained by the two means is minimum. |
