Abstract

A vehicle navigational system and method for tracking a vehicle, including a programmed computer, sensors for sensing the distance traveled and heading of the vehicle, and a stored map data base identifying a map of an area over which the vehicle is moving, in which the computer calculates and advances dead reckoned positions of the vehicle in response to distance and heading data, provides data identifying a contour of equal probability containing the dead reckoned positions and having a probability of containing the actual location of the vehicle, derives multiparameters from the map data base, and updates a given dead reckoned position and the contour using a highly developed vehicle navigational algorithm if a more probable dead reckoned position exists based upon the given dead reckoned position, the contour and the derived multi-parameters.