Coverage Path Planning for Mine Countermeasures: Adapting Track Orientation

Abstract

Capturing high-quality sonar survey data from autonomous underwater vehicles (AUVs) in complex environments, with little to no a priori knowledge, requires built-in adaptations. In particular, in order to locate objects that sit proud on the sea-floor in areas of sand ripples, special trajectory adaptation is required to mitigate natural shadow zones. Adaptive orientation and track spacing are key capabilities, enabling effective search strategies on the sea bottom. We present two methods for adaptive AUV track orientation: the first approach improves mission efficiency (in a resource-utilisation sense) by minimising the number of AUV turns, whereas the second enhances the data collection quality by adapting to sand ripples. A sensitivity analysis compares the two methods and shows that changing the track orientation during a mission is costly in terms of mission efficiency. Results from our study suggest that the adaptation should be applied once there is a considerable ripple field found on the seabed, and should avoid changing the course multiple times during the mission.