METHOD OF DETERMINING DISPLACEMENT OF SURFACE SHIP WITH ITS NOISE DIRECTION-FINDING Russian patent published in 2018 - IPC G01S3/80 

FIELD: physics.

SUBSTANCE: to implement the method, receiving a noise signal by a hydroacoustic antenna, analogue-to-digital converting, detecting, low-frequency filtering, calculating the signal spectrum in the frequency range of fluctuations caused by the rolling of a surface ship are carried out. Then the trend of the spectrum is determined, the centered spectrum is formed, the root-mean-square deviation is determined for the centered spectrum, the normalized spectrum is formed. K of frequency windows of different widths with average values are formed at the frequency of each harmonic of the spectrum n, an array of k×n values of the average power of the process fluctuations is formed in each of the k×n frequency windows, the largest value is selected from the array of k×n values of the average power of the process fluctuations, its frequency in dimension n is remembered. The greatest value is compared with the detection threshold and a decision is made about the presence/absence of the low-frequency fluctuations due to rolling. The displacement of the surface ship is determined according to the table dependence of the displacement from the stored frequency n of the low-frequency signal fluctuation.

EFFECT: increasing the noise immunity of the method and providing the possibility of determining the displacement of a surface ship for any previously unknown width of the low-frequency fluctuations of its signal caused by rolling on sea waves.

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