Automatic Collision Avoidance System: Design, development and flight tests

This paper presents a fully Automatic Collision Avoidance System (ACAS) for unmanned aerial vehicles. This system has been developed by the Italian Aerospace Research Center (CIRA) in collaboration with the department of Aerospace Engineering of the University of Naples "Federico II", in the framework of the national funded research project TECVOL (Technologies for the Autonomous Flight). The proposed system is comprised of two subsystems: the Obstacle Detection and Tracking subsystem, which permits to reveal flying intruders in a selected field of regard and to estimate their motion; the Collision Avoidance subsystem, which provides conflict detection and resolution capabilities, addressed in a 3D environment using information about current position and instantaneous speed vectors. The effectiveness of the system has been demonstrated during a flight test campaign, where proper conflict scenarios have been considered. In fact, the proposed ACAS setup was installed onboard a very light aircraft named FLARE (Flight Laboratory for Aeronautical Research), which has been customized with automatic flight capabilities. System architecture and the developed algorithms are described, then some results obtained from the flight test campaign are presented and discussed which demonstrate the reliability and the efficiency of the developed system.