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The application of levenberg-marquardt algorithm in multi-beam sounding data

For reducing seabed topographic distortion, namely, the random error of the multi-beam sounding, which caused by the sound velocity error, Levenberg-Marquardt (LM) algorithm is introduced to sound velocity correction. The algorithm utilizes the relationship between the sound ray and the sound velocity to establish observation equations, i.e., LM equations. Then, the novel sound velocity profiles are inversed from above-mention LM functions based on the indirect adjustment theory. Finally, the distortion terrain of the seabed is corrected by forward calculating with the calculated sound velocity profiles. The results of field experimental data are shown that: the sound profile values computed by the LM algorithm are more closer to the true value of the sound profile than that of the substitutive sound profile measurements contaminated by the random error, and the mean square error (MSE) of depth correction has been reduced more than 70%, which effectively cut down the influence of the sound velocity on seabed topography.