Autonomous Chemical Plume Detection and Mapping Demonstration Results with a COTS AUV and Sensor Package

Abstract

There is a growing requirement for rapid-response and reliable autonomous detection of environmental hazards in the Arctic where infrastructure is minimal. Lessons learned from recent open ocean oil disasters have exposed a need for commercial-off-the-shelf (COTS) vehicles coupled with inexpensive COTS sensors that collect pertinent data sets that can be easily married across other systems, and easily calibrated and interpreted. A propeller-driven autonomous underwater vehicle (AUV) equipped with a COTS sensor payload is being developed as part of a Department of Homeland Security (DHS) program for under-ice oil detection and mapping. AUVs can greatly increase the efficiency of anomaly detection in an unknown ocean environment by finding the source of the plume and also by effectively mapping out its extent. Such systems could aid in determining the success of countermeasures deployed in a spill such as dispersants. Recent advancements in sensor technology, acoustic communications and vehicle duration make using propeller-driven AUVs a good choice for open water or under-ice detection of oil droplets and other environmental hazards. Near real-time data transfer is a key component in oil response scenarios in order for first responders to make critical decisions as fast as possible in order to limit damages. Using a REMUS-100 (Remote Environmental Monitoring Units) class AUV, we conducted an experiment using a COTS sensor payload to detect and map a subsurface release of fluorescein dye. Any release of oil would include compounds that would be water soluble, or partially soluble and also be fluorescent making fluorescein a reasonable dye to use as an oil surrogate. Our objectives in the experiment were to 1.) Launch and recover the vehicle with two to three people, 2.) Transmit data back to the boat so first responders can make decisions as fast as possible, 3.) Change the mission plan to re-task the search behavior to determine where the plume was and to 4.) Rapidly train United States Coast Guard (USCG) personnel how to program, launch, recover and operate the vehicle. The outcome of the demonstration fit the requirements for an easy-to-use COTS autonomous platform for oil detection needed within DHS. In addition to oil plume mapping, AUV chemical plume tracing capabilities can be used for other chronic and acute events such as unexploded ordinances, harmful algae blooms (HABS), oil and chemical releases from ship wreckages, sources of other hazardous pollutants, as well as creating baseline data sets for establishing the overall health of the ocean ecosystem to be used for damage assessments.Lessons learned from this open water experiment will help to develop a suite of adaptive mapping algorithms that will be transitioned onto a new generation long range vehicle currently being developed for deployment under ice in the Arctic. This development is part of a DHS Center of Excellence known as Arctic Domain Awareness Center (ADAC). Future missions are planned for oil mapping at known release sites in open-ocean followed by under ice operations.