Vehicle-mounted position computing apparatus
First Claim
1. (Amended) A vehicle-loaded position calculating device for calculating the present position of a vehicle on a map by map matching, through comparison between present position information of the vehicle calculated by dead reckoning navigation method and radio navigation method and road data accumulated in a map data base, characterized by traveling lane identifying means for identifying a lane where the vehicle is currently traveling, and position calculating means for judging a branched road, to which the road identified by said traveling lane identifying means is connected, based on said road data and for raising likelihood to be selected of said branched road as the present position of said vehicle.
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Accused Products
Abstract
According to the present invention, even when a road is in such condition that error may occur in detecting the position of a vehicle when only internal sensors are used, a lane on a road where the vehicle is currently traveling is determined, and the error is reduced. Traveling lane identifying means 17 is provided on a conventional type car navigation system, and a lane where the vehicle is currently traveling is identified, and it is inquired to map database as to whether the identified lane is an exclusive lane for right turn, left turn or advancing straight ahead. As a result, when it is found that it is an exclusive lane, processing of the position calculating means 15 is carried out only to a road ahead connected to advancing direction of the exclusive lane. After the vehicle has passed through an intersection, more accurate position can be calculated.
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Citations
3 Claims
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1. (Amended) A vehicle-loaded position calculating device for calculating the present position of a vehicle on a map by map matching, through comparison between present position information of the vehicle calculated by dead reckoning navigation method and radio navigation method and road data accumulated in a map data base, characterized by
traveling lane identifying means for identifying a lane where the vehicle is currently traveling, and position calculating means for judging a branched road, to which the road identified by said traveling lane identifying means is connected, based on said road data and for raising likelihood to be selected of said branched road as the present position of said vehicle.
Specification