Development of Advanced Sonar Sensor Model for Underwater Terrain Mapping based on Occupancy Grids

This paper presents the advanced sonar sensor model capable of building an underwater terrain map based on the Bayes filter in the manner of the occupancy grid. The proposed sonar sensor model basically considers the losses of received ultrasound intensity according to the underwater absorption and reflection on a terrain surface. The Bayes filter including the advanced sonar sensor model is applied to build an occupancy grid map. The underwater sonar data is acquired by the pencil beam type’s sonar sensor mounted on the unmanned surface vehicle (USV). The experimental results show underwater terrain maps before and after applying the proposed method. The depth standard deviations of the terrain grid maps are calculated to evaluate the performance of this approach. With the proposed sonar sensor model, the depth standard deviation average of underwater grid map is decreased by almost 35 percent.