Analysis of Vibration-Induced Errors in UAV-Mounted Optical Particle Measurements

Uncrewed Aircraft Systems (UAS) are rapidly becoming essential tools for high-resolution air quality monitoring. However, integrating low-weight and low-power sensors on UAS platforms introduces specific challenges that can impact data integrity. This study addresses a critical measurement artifact observed using Alphasense OPC-N3 optical particle counters mounted on a DJI Matrice 300. Immediately upon take-off, a reproducible reduction in Particle Number Concentration (PNC) of up to 60 % was detected. Through systematic experimentation, we isolated the source of this error, investigating both rotor downwash and platform-induced vibrations. Contrary to common assumptions regarding downwash effects, our results conclusively identify high-frequency propulsion vibrations as the primary cause of the significant underestimation of particle concentrations. We demonstrate that implementing mechanical decoupling measures successfully eliminates this artifact, restoring measurement accuracy during flight. These findings underscore the necessity for rigorous sensor characterization and integration strategies to ensure reliable mobile air quality data.