Patent ID: 6502033
Filing Date: 2002-12-31
Classification: G01C

Abstract:
A method for determining position and heading of a vehicle relative to a road network represented by a geographic database, wherein the method comprises the steps of:determining a dead-reckoned position and heading along a plurality of road segments in the road network using sensor measurements obtained over a distance traveled by the vehicle; forming a vehicle trajectory history, wherein the vehicle trajectory history includes sensor-derived data representing a vehicle trajectory over a relatively small, chosen distance, and wherein the sensor-derived data include data indicating a heading change of the vehicle, data indicating a vehicle state and data indicating a type of vehicle maneuver; obtaining corresponding data for the distance from GPS measurements; obtaining corresponding data for the distance from the geographic database; using the data in the vehicle trajectory history and the corresponding data from the GPS and the geographic database to determine a corrected dead-reckoned position and heading; and continuously updating said vehicle trajectory history, wherein the vehicle state includes one of: travelling straight, turning and reversing in turn direction within a specified small distance, and wherein the vehicle state of reversing in turn direction within a specified small distance is determined when a heading change for a current and a previous array entry are opposite in sign and both are greater than a threshold.