Development of atmospheric flow and particle measurement UAV based on multi-resolution holographic imaging and full-scale sonic anemometer

A hexarotor UAV system has been developed to conduct simultaneous in situ measurements of atmospheric flow and particles. The atmospheric flow is characterized by a full-scale ultrasonic anemometer with a sampling rate of 20 Hz. In parallel, a multiresolution holographic particle imaging system provides a measurement of the atmospheric particulate size distribution, with a resolution capacity spanning three orders of magnitude from 1 µm to 1 mm. A series of tests have been conducted to test the system’s flight stability and measurement accuracy. Given the constant motion inherent in UAV operation, a data fusion algorithm has been developed to derive wind speed based on sonic anemometer reading and UAV motion. The comparison to Met tower data indicates that the system reliably measures wind speeds with an accuracy margin of 5%. Through different flight modes, the system is capable of measuring the atmospheric boundary layer profile together with other turbulence properties and particle size distribution. In a flight test up to 1000m, cloud droplet data have been successfully collected along with wind data. The results show significant variation in terms of droplet size and flow characteristics at different locations of a cloud with ~100m in size. The UAV system has proven its capability in acquiring highly accurate and versatile quantitative data on flow and particle characteristics, demonstrating potential utility in diverse research fields such as offshore wind energy, cloud dynamics, and marine aerosols.