Collision Avoidance Systems for Autonomous Civil UAVs

The capability to detect and resolve a potential conflict represents a fundamental requirement for every aircraft to operate into the civil airspace. For what concerns the UAVs, there is a growing interest in their operations within non-segregated airspaces, even if their integration in such environments presents many regulatory and technical issues. Among them, the present research deals with the “Sense-And-Avoid” issue and focuses on the “Avoid” requirement. A preliminary step of the present research has been to develop a multi-purpose re-configurable simulation environment to perform real-time repeatable tests. Within such an environment, an UAV can be represented through a six-degree-of-freedom model and equipped as the user requires, with its simulated sensors, auto-pilots and other systems, also including a guidance system to meet the “Avoid” requirement. Then, considering the indications of the regulators about the concept of “Conflict Management”, an “Avoid Strategy” has been defined. Also, a number of “Avoid Algorithms” have been developed to implement the proposed strategy. The main idea has been to describe an intruder through a generic moving ellipsoid that represents a region an aircraft must avoid to violate. Such a proposed approach is suitable to detect and resolve three-dimensional potential conflicts in real-time applications.