Autonomous UAS-based Water Fluorescence Mapping and Targeted Sampling

Uncrewed Aircraft Systems (UAS) are increasingly used in time-consuming and effort-heavy scientific exploration applications. One such application is the inspection of the physical, chemical, and biological properties of water in aquatic ecosystems. This paper presents a novel autonomous UAS capable of sensing water properties and collecting up to three 250 mL water samples from multiple sampling locations. The system features a customized UAS with an in-house built fluorescence sensor and pumping mechanism. The system does in situ fluorescence measurements to map the gradient of fluorescent content across the body of water and determine the best sampling spot for targeted sampling. To ensure safe near-water operation, multiple sensor fusion with an Extended Kalman Filter has been implemented for accurate altitude estimation within 1.5 m from the water surface. To validate the performance of the system, we present experimental results from deployment in two different water ecosystems, namely the Congaree River, SC and Lake Wateree, SC.