Multibeam seafloor topography distortion correction based on SVP inversion

Multibeam bathymetric system (MBS) has been widely applied in marine exploration activities for providing high-precision seafloor topography. However, the representative error of sound velocity profile (SVP) can degrade the precision of sounding and lead to the distortion of seafloor topography. To resolve this problem, we propose a seafloor topography distortion correction method based on the SVP inversion. It firstly decomposes the SVP using the empirical orthogonal function (EOF), which converts the SVP inversion process into the time coefficient optimization process. The time coefficient is then optimized by the simulated annealing algorithm (SA) based on a cost function, which is constructed by the sounding consistency of the corresponding beams in the overlapping areas of adjacent swaths. Finally, the inverted SVP is calculated by the optimal time coefficient, and then the distortion of seafloor topography can be corrected by the inverted SVP. Experiments conducted on three types of seafloor topography demonstrate that the root mean square values of sounding errors of the proposed method are 39.44%, 34.49% and 62.32% lower than the method based on reconstructed SVP in flat, inclined, and undulating topographies, respectively. Compared with the method based on replaced SVP, these calculated by the proposed method are reduced by 88.38%, 88.08% and 92.82%, respectively. These results suggest that the proposed method can significantly improve the precision of multibeam sounding, and efficiently correct the distortion of the various seafloor topographies.