High-resolution bottom detection algorithm for a multibeam echo-sounder system with a U-shaped array

High-resolution approaches such as multiple signal classification and estimation of signal parameters via rotational invariance techniques (ESPRIT) are currently employed widely in multibeam echo-sounder (MBES) systems for sea floor bathymetry, where a uniform line array is also required. However, due to the requirements in terms of the system coverage/resolution and installation space constraints, an MBES system usually employs a receiving array with a special shape, which means that high-resolution algorithms cannot be applied directly. In addition, the short-term stationary echo signals make it difficult to estimate the covariance matrix required by the high-resolution approaches, which further increases the complexity when applying the high-resolution algorithms in the MBES systems. The ESPRIT with multiple-angle subarray beamforming is employed to reduce the requirements in terms of the signal-to-noise ratio, number of snapshots, and computational effort. The simulations show that the new processing method can provide better fine-structure resolution. Then a highresolution bottom detection (HRBD) algorithm is developed by combining the new processing method with virtual array transformation. The application of the HRBD algorithm to a U-shaped array is also discuss. The computer simulations and experimental data processing results verify the effectiveness of the proposed algorithm.