Abstract: A navigation system for a vehicle comprises a central processing unit for executing a plurality of programs including a navigation program and a transmitting program, and an internal nonvolatile storage device electrically connected to the central processing unit through an inner bus and storing therein the transmitting program. The navigation system further comprises an external storage device electrically connected to the inner bus through an interface unit and storing therein the navigation program. The central processing unit is initially operated to execute the transmitting program to read the navigation program from the external storage device and store the read navigation program in the internal nonvolatile storage device, and subsequently operated to repeat the execution of the navigation program stored in the internal nonvolatile storage device to provide a vehicle driver with navigation information including the current location of the vehicle.

Abstract: A vehicle navigation apparatus comprises a control unit for computing an optimum travel route between a departure point and a destination of a vehicle to calculate similarity values each indicating degree of similarity between the pattern of the travel locus of the vehicle and the pattern of each of the travel roads included in a road map. The vehicle navigation apparatus further comprises a control unit for selecting, from the road map, candidate travel roads each having a road pattern having a similarity value exceeding a predetermined similarity level. The candidate travel roads includes a present travel road on which the vehicle is currently traveling. The control unit determines as to whether or not one of the candidate travel roads overlaps with the optimum travel route.