Development and Experimental Validation of a Sense and Avoid System for a Mini-UAV

This paper provides an integrated overview of the three-year effort to design and implement a prototypical SAA system based on a multisensory architecture leveraging data fusion between optical and radar sensors. The work was carried out within the context of the Italian research project named TERSA (Electrical and radar technologies for remotely piloted aircraft systems) undertaken by the University of Pisa in collaboration with its industrial partners, aimed at the design and development of a series of innovative technologies for remotely piloted aircraft systems of small scale (MTOW < 25 Kgf). The approach leverages advanced computer vision algorithms and an Extended Kalman Filter to enhance obstacle detection and tracking capabilities. The “Sense” module processes environmental data through a radar and an electro-optical sensor, while the “Avoid” module utilizes efficient geometric algorithms for collision prediction and evasive manoeuvre computation. Initially, this integrated system has been rigorously tested by means of a sophisticated simulation environment that replicates real-world conditions, including the generation of realistic artificial scenery to evaluate the closed loop interaction between sense and avoid modules in a Hardware-in-the-Loop (HIL) setup. Preliminary results demonstrate the system’s effectiveness in real-time detection and avoidance of non-cooperative obstacles, providing high computational efficiency and responsiveness while ensuring compliance of UAV aero mechanical constraints and safety constraints in terms of minimum distance requirements. At a later stage of the project, the effectiveness of the integrated system was evaluated by means of a preliminary flight test campaign conducted at the Lucca-Tassignano airport in Italy. The findings underscore the potential for deploying such advanced SAA systems in tactical UAV operations, contributing significantly to the safety of flight in non-segregated airspaces.