Research on the Measurement Method of Broadband Radiation Noise Based on Nested Cylindrical Array

The background noise of the ocean gradually increases in shallow sea environments. To meet the increasingly low signal-to-noise ratio requirements for underwater radiation noise measurement, wideband and high gain volume arrays have become the main development direction for underwater radiation noise measurement. Based on the established mathematical model of the cylindrical array, the correlation between directionality and the number of array elements is obtained through simulation analysis. The variation law of the directional index of the array is obtained, which changed with the number of elements and received signal frequency. When the number of elements in the array is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$180(~\mathrm{N} \times \mathrm{M}=12 \times 15)$</tex>, the directional index of the cylindrical array in each operating frequency band is relatively less affected by frequency using the nested array method. The data processing method based on constant beamwidth beamforming technology can achieve distortion free reception of signals, thereby achieving effective measurement of wideband radiated noise.