Route guidance on / off ROUTE GUIDANCE ON / OFF-ROUTE STATE FILTER

摘要

The present invention is to provide a route state filter (74) for a vehicle route guidance system through tracing of the vehicle location for a preselected route. The series of predicted positions is determined by comparing the vehicle position 28 measured with the database 30 containing data representing the road on the map and the expected position corresponding to a possible position on the road within the error region around the measured position do. The route guidance module receives (70) the expected location, checks its validity (72), and filters (74) to remove the likely unlikely expected location. The current position is then selected 76 from the remaining expected position. The on-route and off-route conditions of the vehicle are determined (35, 78) by comparing the selected location to selected route information in the database. The distance-based filter is used to provide improved continuity of path condition determination. The path state is used to set the system operation mode, and the information is transmitted (36, 86) to the driver.;[Selectivity]