Detection of the insonification area of a Multibeam Echo-Sounder using a front propagation

For the execution of its bathymetric surveys, the French Hydrographic and O ceanographic Service of the Navy (SHOM) has been operating three MultiBeam Echo-Sounders (MBES) for three years. These systems carry out simultaneous depth measurements along the transversal axis of the ship, decreasing the t ime for collecting the data. Planning, managing as well as running a bathymetric campaign rely on a synt hetic representation of the area observed by the Echo-Sounder. Representati ons previously used were only based on an approximation of the covered area obtained by making the assumption that the insonification area of each bea m is fixed. This paper proposes an alternative method for building an insonification ar ea based on a standard operation of mathematical morphology: dilation. The originality of our approach lies in its implementation. A reformulation of the dilation in terms of constant fronts propagation to perform a fixed cov ered area allows optimization of both time and precision (Euclidean distanc e). This also gives rises to an efficient implementation of an adaptive dil ation. This results in a more realistic and accurate representation of the covered area in an acceptable processing time. Used during the planning of the campaign, it allows the simulation of a covered area from a rough Digit al Elevation Model and the Echo-Sounder parameters.