| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the erroneous alarm issuing ratio of a system for automatically detecting moving target and to improve the detection ratio of the system when the system automatically detects a moving target. SOLUTION: A frequency analyzing section 1 analyzes the frequency of input signals received from an underwater moving target, calculates the frequency component and spectral level of the signals, and outputs the calculated results to an time-change-not- requiring reflected wave eliminating section 2 and the section 2 outputs the signals to a spectral level threshold processing section 3 after eliminating a reverberation component. The section 3 performs a threshold process with the spectral level threshold corresponding to a background noise level and outputs the processed results to a signal length threshold processing section 4. The section 4 discriminates whether the input signals are the same received signal divided by the spectral level threshold process. A Doppler frequency variation threshold processing section 5 calculates the Doppler frequency variation of the input signal and performs a threshold process on the input signal by using a Doppler frequency variation threshold indicating the upper limit of the Doppler frequency by the real moving target and an azimuth threshold processing section 6 integrates the scattered azimuths and directions of an input signal group and outputs the integrated results as a moving target signal.</p> |
