Patent ID: 7580780

Claim:
A vehicle position detector for use in a vehicle comprising: a position detector for detecting a current position of the vehicle; a map data storage for storing map data including description of roads on a map; a map matching processor for making adjustment of the current position of the vehicle based on the map data; a junction detector for finding a junction having at least two outbound roads extending therefrom based on the map data; a similarity calculator for calculating a similarity index of the at least two outbound roads from the junction detected by the junction detector; and an evaluation processor for evaluating the adjustment of the current position of the vehicle made by the map matching processor, wherein the map matching processor utilizes the current position of the vehicle detected by the position detector, the junction detector detects the junction to which the vehicle is going to enter, the similarity calculator calculates the similarity index of the at least two outbound roads based on the map data when the junction detector finds the junction having at least two outbound roads, the evaluation processor outputs a prospective accuracy level evaluation of the adjustment of the current position of the vehicle for the at least two outbound roads based on the similarity index before the vehicle reaches the junction, and the vehicle position detector is coupled to a vehicle controller comprising a vehicle control unit for controlling a vehicle based on the prospective accuracy level evaluation outputted from the evaluation processor.