| 摘要 |
PROBLEM TO BE SOLVED: To sensitively extract the propagation delay difference between an L2 positioning signal and an L1 positioning signal with a simple structure while suppressing the influence of noises. SOLUTION: A P code replica generator 21 generates two kinds of P code replicas so as to shift from each other by the bit width of a P code. The signal product of the two kinds of the replicas and a Y code extracted from the L2 signal is obtained by multipliers 22, 23. A P code correlator 24 repeats an operation where it obtains signal products obtained by the multipliers 22, 23 at regular sampling intervals and integrates the signal products over a period corresponding to the bit width of the P code, and detects the condition where the signs decided by the integrated values are continuously the same over a period prescribed times the above period, thereby detecting the matching of the P code signal included in the Y code and its replicas. The P code correlator 24 obtains the propagation delay difference between the L2 positioning signal and the L1 positioning signal based on the replicas at that time.
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