The present invention relates generally to vehicle navigation systems and more particularly to a vehicle navigation system, at least significant components of which are transportable between vehicles. Vehicle navigation systems include many expensive components, including a CPU with mass storage, such as a hard drive, CD or DVD, for storing a map database. Navigation systems further include navigational sensors, such as a GPS receiver, accelerometers, gyros, compass, etc. A navigation system further includes a user interface interacting with the CPU, such as a display, audio speaker, and an input device, such as a keypad or mouse. Installation of the known vehicle navigation systems into the vehicle is difficult and must be performed by an experienced trained technician. Although many households own more than one vehicle, the high cost of many of the vehicle navigation system components make installation of a vehicle navigation system into each of the household vehicles impractical.