Patent ID: 8965687
Filing Date: 2015-02-24
Classification: G01C,G08G,G09B

Abstract:
1. 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, comprising: 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; wherein the travel data acquired from the information center include position information of another vehicle and time information of measurement of the position information; and if the acquired travel data include sets of travel data by a plurality of vehicles, the position estimation unit sorts sets of speed information of sections that each correspond to the tunnel in each set of travel data in order of proximity to an inlet of the tunnel, calculates speed information for each of sections divided by the position information, and determines latest speed information in each of the divided sections as a movement speed of the navigation device in each of the divided sections of the tunnel.