METHOD OF DETECTING UW SIGNAL

摘要

PROBLEM TO BE SOLVED: To provide a method of detecting a UW signal capable of preventing erroneous recognition of the UW signal when a demodulation signal superimposed with noise is received.

SOLUTION: The detection method includes: a first step of calculating number of errors in UW codes detected from a received demodulation signal by using a UW code error detector; a second step of discriminating whether the number of errors is a prescribed value or below; a third step of calculating at a receiver side a correlation value between a known UW signal and the received demodulation signal when a result of the discrimination is affirmative; a fourth step of discriminating whether or not the calculated value exceeds a predetermined threshold; a fifth step of calculating a correlation peak point; a sixth step of obtaining a time width between the adjacent correlation peak points and discriminating at the receiver side whether the time width is coincident with a time width between adjacent known UW signals; and a seventh step of recognizing the correlation peak point as a frame synchronization position when results of the discrimination above is affirmative.

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