Time rigid motion compensation and noise reduction of multi-beam bathymetry data (shallow sea).

Abstract

Noises of multi-beam echo sounding cause wrong bathymetry data. In this paper we discuss two improved methods of data processing to reduce noises.
(1) Time rigid motion compensation
Ship motion (rolling, pitching, heaving) affects the location of each footprint. We improved the timing of ship motion used in compensation. We applied new method to real data, and we managed to get more precise bathymetry data than the old one.
(2) Noise filtering using 3D angle of incidence
There is a strong relationship between echo intensity and angle of incidence. Usually, 2D angle of incidence on a plane of projected fan beam is used for noise filtering. However, 2D angle of incidence isn't correct if the bottom is a slope. We introduced a new method to calculate 3D angle of incidence, and applied it to real data.