Evaluation of Altitude Sensors for a Crop Spraying Drone

This work aims to study and compare different range finders applied to altitude sensing on a rotating wings UAV. The specific application is the altitude maintenance for the fluid deployment valve aperture control in an unmanned pulverization aircraft used in precision agriculture. The influence of a variety of parameters are analyzed, including the tolerance for crop inconsistencies, density variations and intrinsic factors to the process, such as the pulverization fluid interference in the sensor’s readings, as well as their vulnerability to harsh conditions of the operation environment. Filtering and data extraction techniques were applied and analyzed in order to enhance the measurement reliability. As a result, a wide study was performed, enabling better decision making about choosing the most appropriate sensor for each situation under analysis. The performed data analysis was able to provide a reliable baseline to compare the sensors. With a baseline set, it was possible to counterweight the sensors errors and other factors such as the MSE for each environment to provide a summarized score of the sensors. The sensors which provided the best performance in the used metrics and tested environment were Lightware SF11-C and LeddarTech M16.