| 摘要 |
PURPOSE:To reduce the route updating frequency and the working load on driver and to improve a sense of use by controlling a route updating threshold in accordance with the route updating frequency. CONSTITUTION:A position detecting means 101 finds out a correlation from the traveling locus of a vehicle and road data stored in a map storing means 102 and collates the correlation result with a measured position result of a GPS to detect the current position of the vehicle. A route selecting means 103 calcuates a route from a current position up to a destination based upon the road data of the means 102 and traffic congestion information received from a traffic information receiving means 104 and stores the calculated route in a storage means 106 together with updating information such as the route updating frequency. A route selecting means 103 reselects a route when traffic information is changed and a route comparing means 105 compares the reselected route with the preceding route stored in the storing means 106 to decide the necessity of route updating. A guiding means 107 calculates a necessary branch point, a distance up to the branch point and a bent direction and an output means 108 displays the calculated results to perform guidance on route. |
