Integration of GPS and dead-reckoning navigation systems

Recent developments of the second generation automotive navigation and route guidance systems have posed more restrictive requirements for vehicle positioning accuracy. Only after accurate current vehicle locations are available can appropriate maneuver instructions be generated from the route guidance algorithm. Dead-reckoning systems and GPS are two commonly used techniques for vehicle navigation systems. While both methods suffer from different drawbacks, superior performance can be obtained by combining these two techniques. In this paper we present a vehicle positioning system that integrates both the GPS and the dead-reckoning method. This system uses the GPS signals to adaptively calibrate the dead-reckoning sensors as well as to "rescue" the system from unexpected position errors. On the other hand, the dead-reckoning method, through the use of map-matching algorithm, provides feedbacks for calibrating the GPS position errors. Experimental results using the ZEXEL NavMate Navigation and Route Guidance System demonstrate the effectiveness of the integrated positioning system.