Low-cost UWB system for mobile robotic facility ground truth measurements

Ultra-WideBand (UWB) technology has an acknowledged importance in the field of localization, particularly for what concerns Global Navigation Satellite Systems denied zones, and space and extraterrestrial environments make no exception. This thesis presents the design and development of a UWB localization system setup for a mobile rover in a 22 x 26 m² open-air facility that mimics the Martian environment. The system is based on commercially available UWB modules and custom hardware, consisting of 12 antenna systems (anchors) placed at three different heights on the perimeter walls of the facility and a mobile tag on the robot. The ranging information is processed by a ROS2 node implemented on the rover, which employs Kalman filters to estimate the pose of the robot using the trilateration algorithm, based on the known absolute positions of the anchors. The thesis includes the design of a custom PCB to adapt the 24V AC power supply of the facility to the 12V DC voltage required by the microcontroller, the 3D modeling of a detachable waterproof case for the antenna system, and the development of a 3D graphical simulator of the facility terrain and the rover using ROS2, to test filter algorithms and features and to emulate the real behavior with noisy measurements. Simulation tests show extremely precise tracking on the XY plane, with average errors of about 5 cm, while in experimental tests they stand on about 10 cm but still provide a reliable localization of the rover, also by virtue of an extensive activity of calibration and error mapping. Overall, this thesis presents a low-cost and high-performance UWB localization system for mobile robotics, providing ground truth measurements for facility tests but also making it suitable for a possible setup in the extraterrestrial outposts of tomorrow.