| 摘要 |
PROBLEM TO BE SOLVED: To detect a TII(transmission identification information) from among DAB(digital audio broadcasting) signals, and to obtain the present position from the TII and transmitter information stored in a memory when any radio wave is not received from a GPS(global positioning system) satellite. SOLUTION: This device is provided with a judging means 106 for judging whether or not an position measuring operation is valid from a radio wave from a GPS satellite, and switches this to reception by a DAB when the position measuring operation is invalid, TII detecting means 108 for detecting TII from among the demodulated signals of the DAB, memory 109 for storing the transmitter information of each transmitter, and second arithmetic means 110 for detecting the received position of a mobile object from the transmitter information and the detected TII. When it is judged that the position measuring operation is invalid from the radio wave from the GPS satellite by the judging means, this is switched to reception by the DAB, the TII is detected, and the received position of the mobile object is calculated from the detected TII and the transmitter information from the memory. Thus, this processing can be substituted for the position measuring operation from the radio wave from the GPS satellite. |
