| 摘要 |
PURPOSE:To navigate a vehicle in a short time by performing switching to dead reckoning type search processing unless a certain estimated position is obtained after network search type search prcessing is carried out preferentially. CONSTITUTION:A 1st estimated position (b) obtained by a network search type searching method is used preferentially to shorten the search processing time in a normal travel state. If, however, the certainty of the position (b) found by the network search type searching method is lower, a 2nd estimated position (c) is searched for by a dead reckoning type search method to realize vehicle navigation free from a failure in map matching. Further, when the position (b) by the network method and the position (c) by the dead reckoning method are both low in certainty, the current estimated position is found according to an integral estimated position (d) to prevent a failure in map matching as to, for example, a Y-shaped road. |
