| 摘要 |
PROBLEM TO BE SOLVED: To measure the position of its own device accurately and inexpensively even in such a condition that GPS signals are cut off. SOLUTION: A cellular phone is connected to a navigating ECU having a GPS receiver through a connecting means. When the power source of a vehicle is turned on, the receiving condition of the GPS signal received by the GPS receiver is ascertained (S3). In the case the signal can be received (S4; Y), the current position of the own vehicle is accurately measured based on the GPS signal. In the case the power source is turned off at the preceding operation in such the condition that the GPS signal cannot be received (S2; Y), and in the case a sunshine sensor makes such a judgement that the own vehicle enters a construction such as an underground parking lot, a tunnel or the like (S8; Y), or in the case the current position of the vehicle is determined on a building street, the underground parking lot, the tunnel or the like (S10; Y) by referring map data, the cellular phone sends a signal automatically to a positional information service center and obtains position data (S11), and the position of the own vehicle is measured based on the positional data (S12). COPYRIGHT: (C)2003,JPO |
