Patent ID: 8332149

Claim:
A navigation device that corrects an estimated path found by dead reckoning navigation, the navigation device comprising: a controller that: acquires a plurality of GPS positions based on GPS positioning; acquires a plurality of estimated positions and a plurality of candidate positions based on dead reckoning navigation, each of which respectively correspond to the acquired GPS positions; determines an estimated path that is made up of the plurality of estimated positions; determines a candidate path that is made up of the plurality of candidate positions; acquires a speculative maximum error that specifies a distance of an error range with respect to each GPS position; calculates a point correlation value for each estimated position based on a distance between the estimated position and a reliability circle, the reliability circle having a radius equal to the acquired speculative maximum error; calculates a correlation value of the estimated path that is a cumulative value of point correlation values calculated for each of the plurality of estimated positions; calculates a correlation value for each candidate position based on a distance between the candidate position and the reliability circle; calculates a correlation value of the candidate path that is a cumulative value of the point correlation values calculated for each of the plurality of candidate positions; and performs a correction of the estimated path that moves the estimated path if the correlation value of the candidate path is equal to or less than the correlation value of the estimated path, but does not perform the correction if the correlation value of the candidate path is greater than the correlation value of the estimated path.