Research and Implementation of Real-time Roll Compensation Technology for Multi-beam Bathymetric System

The ship roll influences the measurement of multi-beam, the movement of ship lead to the swath is not uniform. In order to cover wider sea areas, one approach is to improve the overlap rate of adjacent area. However, this approach has a defect that decreases the measurement efficiency. In this paper, the method of real-time compensation technology was adopted to increase the measurement efficiency. According to roll angle, real-time calculate the beam angle, each measurement has stationary beam angle compare with land coordinate system, and the swath is uniform, in the case of full coverage, the overlap rate of adjacent area would reduce, therefore, measurement efficiency is improved. In the process of real-time roll implementation, due to the slow change rate of roll and the complicated calculation for beam angle, hence the NIOS II was presented. However, the forming of beam directly connect with sample points, demanding real-time, hence the FPGA logic was presented. Take the advantage of real-time calculation and decrease the demand of logic resource properties, demonstrated that this approach could increase the measurement efficiency.