| 摘要 |
PROBLEM TO BE SOLVED: To provide a navigation system making possible to reduce power consumption by cutting of a power supply to a GPS receiver in a reception disabled area. SOLUTION: The navigation system comprises a GPS receiver for receiving radio waves from a GPS satellite; a power source switching section for supplying or cutting off power to the GPS receiver; a map storing section for storing map data having information whether radio waves for the GPS satellite can be received; and a control section for searching a route from a departure place to a destination based on map data that has been stored in the map storing section, calculating a present place based on an output of the GPS receiver, detecting whether there is a road that cannot receive radio waved from the GPS satellite towards the front of the present place, and then cutting off the power supply for the GPS receiver to the power source switching section for a predetermined time when there is a road that cannot receive radio waved from the GPS satellite. COPYRIGHT: (C)2008,JPO&INPIT |
