A UAV-based system for detecting natural gas leaks

We describe an integrated system combining an unmanned aerial vehicle (UAV) and open path methane instrument for detecting leaks in natural gas infrastructure. Reducing methane emissions from the natural gas supply chain is a focus of industry and government initiatives to reduce greenhouse gas emissions. UAVs may provide a more cost-effective, accurate, and safe approach to finding leaks than existing technology. The base UAV is a 2.3 m wingspan fixed-wing, battery powered autonomous UAV, capable of 90 min flight time. The methane instrument consists of a tuneable laser diode absorption spectrometer, mounted with a transceiver unit on one winglet, a retro-reflector on the other winglet (path length = 4.6 m), and measurement control boards in the main fuselage. Operationally, the aircraft flies a predetermined sequence of waypoints downwind of the pipeline or infrastructure. Measured methane concentrations are passed to the UAV flight computer, geotagged, and stored for analysis upon landing. If measured concentrations exceed a certain threshold, a "loopback routine" in the flight computer directs the UAV to turn around and fly over the methane anomaly to collect additional data. We demonstrate the operation of the system for commercial leak detection in upstream natural gas pipeline networks.