NAVIGATION DEVICE AND METHOD WITH FUNCTION OF ESTIMATING POSITION WITHIN TUNNEL

A navigation device that includes a map data base in which map information is stored and a positioning unit that determines a current position based upon a radio wave signal received from a satellite, contains: a tunnel detection unit that detects a tunnel that is present ahead on a road where the navigation device is moving; a travel data acquisition unit that acquires travel data of another vehicle from an information center; and a position estimation unit that in case the tunnel detection unit detects a presence of a tunnel ahead on a road where the navigation device is moving and the travel data acquisition unit acquires from the information center travel data of another vehicle that has traveled through the detected tunnel, estimates a current position of the navigation device in the detected tunnel using a travel speed in the detected tunnel in the acquired travel data as a movement speed of the navigation device.