WATER TEMPERATURE MEASUREMENTS BY AN UNMANNED AERIAL SYSTEM (UAS) OF POWERPLANT HOT WATER DISCHARGES

We report on the development and testing of a proof of concept water temperature measurement system that is used in conjunction with an unmanned aerial system (UAS). The system is comprised of a quad-copter UAS which carries, for the first time, both a thermal imaging infrared (IR) camera and an immersible probe that can be dipped below the surface of the water to obtain a vertical water temperature profile. The IR camera is used to geo-locate the phenomena of interest while the immersible probe provides quantitative temperature depth profiles at specific locations. The immersible temperature probe contains both a pressure sensor and thermistor so that it could function separately from the platform, was controlled by micro-controller mounted to the UAS, and has a magnetic decouple to allow the sensor to detach from the drone in the event of a snag. This system was designed to measure thermal discharges coming from power generation facilities into cooling reservoirs or other bodies of water, but due to its portable and configurable design could monitor many types of hydro-thermal phenomena. The entire system has been tested including the autonomous navigation of the UAS, its ability to safely carry the sensor payload, and the performance of both the IR camera and the temperature probe. This testing culminated in the successful deployment of the system in a pilot field study at a coal burning power plant from which images and temperature profiles of the thermal discharge were generated. We were able to achieve temperature accuracies of ±1˚C and depth accuracy of ±3in (76mm) with location accuracies from the UAS of within 3ft (1m).

Keywords: UAS, infrared imaging, temperature profile, thermal plume