Offset calculation for traffic scenarios

Abstract

The integration of unmanned aerial systems (UAS) and remotely piloted aircraft systems (RPAS) will play a key-role in the world-wide aviation for the next years. In order to safely integrate UAS in the existing manned aviation, they have to follow the same rules and commands as manned aviation currently does. One of the major challenges is to carry out proper detect and avoid (DAA) with such vehicles. A proper working DAA is essential in certain airspaces where separation from other airspace users is not provided by ATC. To ensure a safe detection one possibility is to equip the vehicle with active sensors that can sense surrounding traffic. To evaluate the level of safety, an understanding for minimal detection ranges of such systems has to be established. Where ATC is not responsible for separation, pilots are responsible to stay “well-clear” from each other. Manned aviation works with such an imprecise rule, but a DAA system needs exact numbers for minimum separation distances in order to “remain-well-clear”. The numerical approach in this paper shows one possibility to calculate the offset of trajectories in different representative traffic scenarios. The offset shall be of a size to just not trigger TCAS (Traffic Collision Avoidance System) RA (Resolution Advisory) alerts, but can be used to evaluate DAA algorithms. The number of traffic scenarios defined for this paper aim at covering most cases encountered in practice. Thus, the simulation scenarios constructed from these principles can be used to determine minimal sensor detection ranges that a real-world system has to adhere to in order to be considered safe in mixed-traffic operations.