Active Sonar-Driven Iceberg Wall Following Path Planner for Autonomous Underwater Vehicles

Autonomous Underwater Vehicles (AUV) are potential candidates for mapping icebergs in a safer manner compared to using manned ships. However, iceberg drifts and irregular contour pose challenges for AUVs when maneuvering around the iceberg at a constant stand off distance autonomously. To this end, in this paper, we present a novel approach for generating guidance path for an AUV based on an Occupancy Grid Map (OGM) constructed from the measurements from a Mechanical Scanning Imaging Sonar (MSIS). The method consists of three components: MSIS data pre-processing, path generation and waypoint selection, to realize the autonomous iceberg wall-following behaviour. The presented method is generalized and can be utilized for other online wall following applications. The autonomy system is validated in a simulation environment where the AUV has successfully circumnavigated different icebergs at desired standoff distance of 20 meters and has produced an overall root-mean-square-error less than 4m.