| 摘要 |
PROBLEM TO BE SOLVED: To suppress the power consumption and extend the operating time for battery drive by intermittently receiving signals containing the time information from a position measuring satellite, extracting the time information, and correcting the clocking content of a clocking means. SOLUTION: The GPS antenna signal is frequency-converted (1) by the signal generated by a VOC 2 and converted into digital data (4). A carrier NCO 6 generates the frequency signal based on the control data a CPU 10, and a multiplier 5 multiplies the output data 4, 6 and generates the signal removed with the carrier component. A PRN code generating circuit 8 generates the C/A code specified by the data of the CPU 10 in the specified phase, and a correlator 7 correlates the carrier removal signal and the C/A code. The CPU 10 reads, calculates, and feeds the correlated data to the circuits 8, 6 to synchronize the C/A code phase and the carrier frequency. The navigation message data are extracted, the present time is obtained from the contained time information, and the clocking content of a clocking circuit 16 and the timer clocking content of a control circuit 15 are corrected. |
