A Correction Method for Multi-beam Roll Residual Based on LM Algorithm

  Objectives  To solve the problem of periodic undulations like "wave" at the edge of data strip caused by roll residual due to motion residual of multi-beam echo sounder, a correction method for multi-beam roll residual is proposed on the basis of LM(Levenberg-Marquardt) algorithm.

  Methods  By establishing the functional relation between the depth of water and the roll residual, this method uses the nonlinear least square LM algorithm and combines the idea of profile trend line construction to extract the roll residual, and realizes the correction of the submarine topography. This method fully takes into account the basic trend of the seabed and the influence of rolling residual on the water depth, which has high theoretical feasibility.

  Results  The results show that the transition of submarine topography was much smoother after correction, and closer to the real seabed; the STD(standard deviation) of port and starboard depth profiles decreased by more than 50%, while the mean of the depth profiles almost unchanged; the similarity of the two groups of roll was calculated and the roll residual was preliminarily judged to include delay of roll and shaking of the pole.

  Conclusions  This method can extract the systemic roll residual accurately, and the STD of submarine topographic undulations is significantly reduced after the correction, and the effect of motion residual on multi-beam data is effectively weakened.