Numerical modeling of the 2D hologram of the low-frequency moving source by using horizontal antenna in a shallow water waveguide

Abstract

The 2D holographic signal processing method by using a horizontal linear antenna (HLA) in shallow water is considered in the paper. The offered method of moving broad band source sound field hologram formation by using HLA is based on holographic signal processing of each element of HLA. The sound source moving in shallow water waveguide creates a stable interference pattern (interferogram) in the frequency-time domain on each HLA element. The 2D-FT (2D Fourier Transformation) of the interferogram is antenna element hologram (AEH). AEH allows to coherently accumulate the sound intensity of the interferogram in a small area as focal spots for each HLA element. It is shown in paper that the focal spots localization in AEH of HLA depends upon the source range, velocity, and motion direction [S. Pereselkov and V. Kuz’kin, JASA 151(2), 666–676). The output HLA hologram is formed by superposition AEH. Relationship between focal spot coordinates on the HLA hologram and the source range, velocity, and motion direction are derived in the paper. The results of the numerical experiment of HLA hologram formation for low-frequency (100–400 Hz) sound field of source moving in shallow water are presented. The results presented in the paper significantly expand the efficiency of interferometric signal processing in shallow water. [This study was supported by RFBR 19-29-06075, МК-4846.2022.4.]