An apparatus for correcting distance error in a navigation system

Claim 1

A distance information correction device for use in a navigation apparatus for guiding a vehicle, having a distance sensor for detecting a present position of said vehicle, and a route searching means for providing a route of travel to a guidance point on the basis of said detected present position, intersection data, road data and node data, said node data including information about points along a road and distances therebetween; said distance information correction device comprising: first distance determining means for determining a distance of said vehicle from said detected present position to a next node along said route of travel and whether said determined distance is within a predetermined range of distance error correction; second distance determining means for determining whether said determined distance equals zero; display means having a first output means for displaying information about said next node relative to said detected present position, second output means for outputting information about distance error correction when said determined distance is within said predetermined range of distance error correction, and third output means for outputting information about zero distance when said determined distance between said detected present position and said next node equals zero; input means for permitting a driver of said vehicle to input a node passage information when said vehicle passes said next node as displayed by said first output means; and distance error correction means for correcting any error in travel distance to said guidance point by correcting said travel distance based upon said distances contained within said node data when said node passage information is input through said input means.