Enabling Under Ice Glider Operations: A Backseat Driver Approach

Polar Oceans are key locations for forcing global ocean circulation, influencing both global climate and biogeochemical cycles. Due to restricted access to these seasonally and perennially ice-covered regions, these areas are severely undersampled. As such, there is an ongoing demand to expand the capabilities of marine robotics to enable observations here, especially during the winter months when many of the most important climate processes (e.g., dense water formation and carbon sequestration) occur. Underwater gliders are increasingly required to operate in ice-covered regions, both for short-term missions lasting days and long-term excursions extending over several months. The standard control system of Slocum gliders, while equipped with ice coping behaviors, is not designed for deliberate under-ice missions. To enhance the capabilities of Slocum gliders, the authors present a backseat driver system coupled with an upward-looking altimeter designed to enable more complex missions and ensure safe surfacing clear of the ice. The backseat driver is an additional control system that enables advanced decision-making using a combination of the glider's own state information and scientific sensor measurements. This backseat driver allows gliders to (1) change heading adaptively, (2) sense the presence of and avoid collisions with ice, (3) customize surfacing considering ice extent, and (4) trigger contingency behaviors in the event of faults beneath the ice. The developed backseat driver was tested through lab and field trials and has been deployed for a long-term deployment in the Weddell Sea as part of the UK's National Capability BIOPOLE program, with short-duration under-ice missions.