Horizontal and vertical wind speed sampling using multirotor UAS aircraft

The utilization of multi-rotor UAS aircraft for atmospheric data collection is an expanding field, and one method employed for measuring atmospheric wind speed is the so called tilt angle method. This method correlates the tilt angle assumed by the multi-copter during hovering to compensate for aerodynamic drag forces due to the atmospheric wind.At the Umweltphysik Group of the Eberhard Karls Universitt Tbingen, a cost-effective and easily replicable calibration method has been devised and tested. However, this approach overlooks the crucial vertical component of the wind, essential for calculating vertical turbulent fluxes.To address this limitation, a follow-up study proposes an analytical approach that involves calibrating relationships between wind speed and tilt angle, motor RPM and tilt angle, as well as vertical wind speed and RPM. The necessary data for this calibration can be obtained through telemetry from an open-source flight controller's log files and proper electronic speed controllers.Accurate calibration of these relationships is ensured through real-world flight testing to maintain high precision. Indoor tests or wind tunnel experiments might yield biased results due to interactions with walls, failing to accurately represent the aircraft's outdoor aerodynamic behavior.Considering environmental parameters such as air density is vital, as evidenced by notable differences between calibrations conducted in winter and summer. These variations underscore the necessity of accounting for environmental influences to avoid constant biases in the wind retrieval.Subsequently, the method will undergo further validation by flying the aircraft in close proximity to a sonic anemometer to assess its accuracy in measuring atmospheric parameters.