In a navigation system which has sensors for detecting a running distance, an azimuth, etc. of a vehicle, and a memory for storing map data; a probability density of a position of the vehicle is calculated on the basis of the sensor outputs and the map data for each of quantization units with which a...http://www.google.ca/patents/US5311173?utm_source=gb-gplus-sharePatent US5311173 - Navigation system and method using map data
