Atmospheric effects on rotary LiDAR-based systems for UAS missions

Urban Air Mobility (UAM) and Advanced Air Mobility (AAM) are new air transportation concepts in urban areas, both based on Unmanned Aircraft Systems (UAS). The last decade has witnessed a constant growth of UAS missions in urban areas, for various military operations, civil and scientific tasks. During UAS missions, identification and tracking of the surrounding environment is fundamental (e.g., obstacles or other vehicles, stationary or moving). It is therefore crucial to test atmospheric effects like temperature, pressure, and humidity variation on the on-board or ground sensors. This paper investigates the effects of temperature and relative humidity variation on rotary LiDAR (Light Detection and Ranging)-based distance measurements, to characterize its functionality by simulating several weather conditions. The objective this work is characterizing the sensor and validating a mathematical model of distance measurements in the presence of temperature and humidity variations. The rotary LiDAR is part of a ground control station system prototype for UAS operations, recently developed by the authors, to date tested and validated only in indoor scenarios. The core of the system is a real-time mechanically rotating LiDAR sensor (RPLIDAR Model A1M8), linked to a Raspberry Pi 3 board for data management and interfaced to a PC-based ground station.