Aerial Survey Robotics in Extreme Environments: Mapping Volcanic CO2 Emissions With Flocking UAVs.

We present methods for autonomous collaborative surveying of volcanic CO₂ emissions using aerial robots. CO₂ is a useful predictor of volcanic eruptions and an influential greenhouse gas. However, current CO₂ mapping methods are hazardous and inefficient, as a result, only a small fraction of CO₂ emitting volcanoes have been surveyed. We develop algorithms and a platform to measure volcanic CO₂ emissions. The Dragonfly Unpiloted Aerial Vehicle (UAV) platform is capable of long-duration CO₂ collection flights in harsh environments. We implement two survey algorithms on teams of Dragonfly robots and demonstrate that they effectively map gas emissions and locate the highest gas concentrations. Our experiments culminate in a successful field test of collaborative rasterization and gradient descent algorithms in a challenging real-world environment at the edge of the Valles Caldera supervolcano. Both algorithms treat multiple flocking UAVs as a distributed flexible instrument. Simultaneous sensing in multiple UAVs gives scientists greater confidence in estimates of gas concentrations and the locations of sources of those emissions. These methods are also applicable to a range of other airborne concentration mapping tasks, such as pipeline leak detection and contaminant localization. [ABSTRACT FROM AUTHOR]