Long-Endurance Optical Seafloor Imaging using Underwater Gliders: Concept, Development and Initial Trials

In-situ observation of the deep-sea floor is a fundamental need for marine sciences and ecosystem monitoring. This work proposes a novel robotic approach for benthic observations in the deep sea using underwater gliders. The glider is equipped with a downward looking camera system to acquire high resolution optical images of the seafloor. The system works fully autonomous and has the potential for long-endurance missions at low deployment costs. Key factors for long battery lifetime are a low power consumption during idle phases, a timely activation of the main imaging system and an efficient lighting setup. The results of our initial trials at sea using a 1000m glider show the applicability of the approach for marine science applications. We achieved optical image quality utilizable for seafloor classification and 3D reconstruction of underwater objects. Keeping the vertical zig-zag motion of underwater gliders in mind, our findings substantiate the feasibility of multi-week seafloor observation missions at long operating ranges.