Adaptive algorithm for holographic processing of broadband hydroacoustic signals

Within the framework of numerical modeling, the adaptive algorithm for holographic signal processing of a sound source in a shallow water waveguide is verified. The sound source creates a stable interference pattern of intensity distribution (interferogram) at the receiver point in the frequency-time domain. The 2-D Fourier Transformation (2-D-FT) is applied to analyze the interferogram of the source moving in the waveguide. The 2-D-FT of the interferogram is referred to as a hologram (S. Pereselkov and V. Kuz’kin, JASA 151(2), 666–676). Adaptation within the framework of holographic signal processing is understood as the evaluation of processing parameters depending on specific propagation conditions. These processing parameters are aimed at the optimal estimation of the radial velocity and distance of the source. The evaluation of processing parameters implemented at the source detection step enables the determination of differences in the horizontal mode wavenumbers and their derivatives for various combinations of sound field modes. The proposed adaptation algorithm addresses the challenge of low-noise source localization in shallow water where acoustic calibration is not possible or where data about hydroacoustic conditions is unavailable. The adaptive algorithm significantly expands the applicability of holographic signal processing for the localization of low-noise sound sources. [This research was supported by a grant from the Russian Science Foundation (Grant No. 23-61-10024)]