Towards the Development of an Online Coverage Path Planner for UUV-based Seafloor Survey using an Interferometric Sonar

Seafloor survey is an important practice for both defense and scientific purposes. Often time, we could refer the seafloor survey mission to as a coverage path planning (CPP) problem where the robot has to explore all the points of an area. In this paper, we propose a new online CPP algorithm for a UUV equipped with an interferometric sonar that has inherent problem of nadir gap and changing swath width. The proposed algorithm will account for the above two factors, and schedule new waypoints for the UUV intermittently. The way-points are determined based on an objective function quantifying the potential measurement accuracy and information gain. We present the algorithm validation in a simulated environment with a 6DOF REMUS AUV model with an actual bathymetric map of Narragansett Bay, Rhode Island. The proposed algorithm is compared to boustrophedon coverage path at different inter-distances. In the result, we found advantages of the proposed algorithm in terms of total path length to fully explore a 200 by 500 meters rectangular workspace.