Spatial domain dedispersion transform and its application extracting horizontal wavenumber structure.

Dispersion and multipath effects contribute to the complexity of the shallow water acoustic field. However, this complexity contains valuable information regarding both the waveguide and the acoustic source. The horizontal wavenumber and relative amplitude of the modes comprising the acoustic field are crucial pieces of information for addressing acoustic inversion problems in shallow water. However, when employing a horizontal array to extract this information, limitations arise due to array aperture and signal-to-noise ratio constraints. To attempt to solve these challenges, the approach of spatial domain dedispersion transform and frequency domain accumulation is proposed. The objective can be attained by leveraging broadband source with slowly varying phase spectrum or known phase spectrum under the constraints of small aperture arrays and low signal-to-noise ratio. Additionally, the approach is validated on dual-hydrophone horizontal array by relaxing the signal-to-noise ratio requirement. In this paper, theoretical proof of the algorithms' performance is provided, accompanied by analysis of the impact of parameters such as acoustic source bandwidth, the number of elements and array aperture. The effectiveness of the algorithms are validated through simulations and experimental data.