Position detection apparatus and position detection program

Abstract

A position detection apparatus includes a storage unit for storing map information including road information; a detection unit for detecting information for calculating an absolute position of a moving object; a position calculation unit for calculating the absolute position of the moving object and an error variance relating to an error of the moving object from the detected information; a read-out unit for reading out from the storage unit the road information of a road relating to the calculated absolute position; an existence probability calculation unit for calculating an existence probability of the moving object existing on the road from the absolute position, the error variance, and the read-out road information; a selection unit for selecting a position whose existence probability is maximum out of the calculated existence probability; and a map-matching processing unit for making the selected position a position of the moving object on the road.