Research on the Multibeam Bathymetry Problem in Uneven Seabeds Based on Computational Geometry

Abstract

The principle of the multibeam seabed bathymetry system involves emitting dozens to hundreds of beams at once in a plane perpendicular to the course, and then receiving the acoustic waves returned by the seabed through the receiving transducer. This paper will study through computational geometry how to calculate information such as seabed depth, survey line coverage width, and the overlap rate between survey lines based on the received information in uneven seabed areas. This study first discusses the special case where the survey line is parallel to the contour line, defining coverage width and overlap rate. It then uses the sine theorem and triangle solving to calculate physical quantities such as seawater depth, coverage width, and overlap rate with the previous survey line when the seabed has a slope. Sensitivity analysis is conducted from three aspects: depth, slope, and opening angle. This research continues to discuss the general case where the survey line is not parallel to the contour line. By first calculating the angle between the intersection line generated by the seabed section detected by the vessel and the seabed slope surface and the horizontal plane, the problem is transformed into the model under the parallel situation to continue the calculation and solve the coverage width. The study of multibeam bathymetry in uneven seabeds using computational geometry enables the application of multibeam bathymetry in uneven seabed areas, providing a simple calculation method for the field of bathymetry in uneven seabeds and expanding the application conditions of multibeam bathymetry.