Comparison and Analysis of Sound Velocity Error Correction Methods Based on Multibeam Sounding Data

Abstract

In order to reduce the sound velocity error of multibeam sounding in flat seabed, the equivalent sound velocity profile (SVP) method and the adjustment inversion method are introduced to sound velocity correction. The equivalent SVP method use the normal gradient SVP to replace the original SVP based on the relationship between sound velocity value and depth, and correct the seabed topography. The inversion method utilizes the relationship between the sound ray and the sound velocity to establish observation equation. Then, the inversion SVP are calculated from the normal equation based on the indirect adjustment theory. Finally, the distortion terrain of the seabed is corrected by the inversion SVP. The results of field experimental data are shown that: the seabed topographic values computed by the equivalent SVP and the inversion SVP are both closer to the true value of the SVP than that of the original error data. And the mean square error of depth correction has been reduced 61.3% and 72.5%, which effectively cut down the influence of the sound velocity error on seabed topography signal. And the computational efficiency of adjustment inversion method is better than the equivalent SVP method.