| 摘要 |
PROBLEM TO BE SOLVED: To provide a navigator which can detect the abnormality of a vehicle- side beacon receiving system even at a location where no beacon equipment is installed and, at the same time, can easily and surely discriminate the abnormality. SOLUTION: A navigator is preset to execute abnormality discrimination when the power supply to the device is turned on and, when the device discriminates abnormality, the device outputs an output-up command and preset standard data to an optical beacon transmitting-receiving unit 24. The navigation device transmits an optical signal composed of standard data from a light emitting element 26 in a state where the illumination power of the signal is increased from that at normal time and receives the reflected light of the transmitted light from the rear surface 25c of the light transmitting section 25a of an optical beacon head 25 by means of a light receiving element 27. When the data of the received light coincide with transmitted standard data, the device discriminates that no abnormality exists. When both data do not coincide with each other, the device discriminates that abnormality exists. Therefore, even at a location where no beacon equipment is installed, the device can discriminate abnormality. |
