| 摘要 |
PROBLEM TO BE SOLVED: To detect the synchronization between the clear access codes of a satellite and a receiver by enabling a data processing device to control the center frequency and the band width of a band-pass filter while capturing a signal. SOLUTION: At a stage where a receiver identifies a clear access (C/A) code and searches a GPS satellite, a feedback loop 5 searches the correlation between the local code generated by the receiver and a reception signal from a satellite. In this case, a data processing device 11 controls the filter coefficients of band-pass filters 48-50 when starting capturing and demodulates the center frequency of each pass band. Then, the band width of each band-pass filter for detecting a demodulation signal is divided into a band width with the center frequency of the demodulation signal as the center frequency. Further, the signal is divide again more accurately. Namely, the device 11 controls the center frequency and the bandwidth of the filters 48-50 and divides one of the bandwidth at a preceding stage into a bandwidth which does not overlap at each stage, thus detecting the synchronization of the CIA codes of the satellite and the receiver. |
