A route navigation system including portable device

A route navigation system with facilities for long-term power supply, data processing, data storage, and berth means for reversibly positioning a device that in a removed state allows stand-alone navigation, a bertheable navigation device and a vehicle-based navigation sub-system for use in such system, and a vehicle provided with such system or subsystem. A navigation system for effecting route navigation from a first location along an optimized route to a destination location comprises vehicle-based facilities for long-term power supply, data processing, and data storage viz à viz the navigation of said vehicle. In particular, the system comprises vehicle-based berth means for accommodating reversible positioning of a navigation device that in a berthed state allows sharing of the vehicle-based facilities for collectively constituting said navigation system but in a removed state allows stand-alone navigation away from said vehicle-based facilities.