Navigation system equipped with portable sub-navigation unit

摘要

A navigation system (100) comprises a navigation apparatus (110) mounted on a vehicle (101) and a portable information device (120) communicable with the navigation apparatus based on a predetermined communication protocol. The navigation apparatus searches a route from a current position to a destination, and guides the searched route to the vehicle, that is, crews on board. The navigation apparatus further comprises a unit (111-113, 116, 117(S6-S7)) for searching a further route from a further current position to the destination in response to a predetermined command. The further current position is a position at which the unit searches the further route. The navigation apparatus further comprises a transfer unit (113, 117(S5, S8)) for transferring information indicative of the further route to the portable information device. This device provides a person, who carries the device, with a further route guide by showing the further route, after the route guide performed by the navigation apparatus.