Lead and lag correction in vehicle navigation system

The reasons were analyzed, which causes lead and lag errors in vehicle navigation system. A method was proposed, which uses map matching to correct lead and lag errors in global positioning system/dead deckoning system (GPS/DRS) integrated navigation system. The method transforms lead and lag errors into GPS errors, which could be emended by map data on the basis of the observability of GPS errors along the vertical direction. Kalman filtering was constructed to process the information of corrected GPS and DRS later, which decreases lead and lag errors in the integrated navigation system.