The holographic signal processing for the estimation of sound mode parameters in shallow water

Abstract

The holographic method for estimation of the broadband sound field modes parameters by using a single receiver in shallow water is presented in the paper. The holographic method of signal processing is based on the two-dimensional Fourier transform (2D-FT) of the source moving in the shallow water waveguide. The sound field creates in waveguide a stable interference pattern (interferogram) in the frequency-time domain. The result of the 2D-FT of the interferogram is called the Fourier-hologram (hologram). It is shown in the paper that different sound field modes create different focal spots in the hologram domain. The filtering focal spots and applying the inverse 2D-FT to them allows restoring the field of the selected mode. In relation to the time-warping operator, the proposed method of signal processing provides a smaller error in the mode group velocity estimation. The results of the numerical simulation as well as the sound mode parameters estimation are presented and discussed in the paper. [Work supported by the RFBR (19-29-06075) and МК-6144.2021.4.]