Small Multirotor Unmanned Aircraft Collision-Avoidance at Low Altitude with Remain Well Clear and Speed Control

This paper investigates the performance of a prototype airborne collision avoidance system (ACAS) algorithm for multirotor small unmanned aircraft system (SUAS) platforms operating at low-level within the National Airspace System. As the number of these multirotor SUAS platforms operating at altitude of 200-400 feet increases, a robust collision avoidance system will be needed to avoid near midair collision (NMAC). A prototype ACAS algorithm was developed that builds upon the ACAS X framework and is tailored to take advantage of SUAS platform flight dynamics. This paper expands previous research by adding a remain well clear (RWC) requirement to a resolution advisory (RA) with variable dynamic maneuvers and speed control to avoid NMAC. The performance of this prototype ACAS algorithm was investigated through various simulations where the occurrence of NMAC was used as an evaluation metric. These simulation results show that NMAC can be reduced by including both RWC and RA requirements with dynamic maneuvers and variable speed control. These results may be used to support the definition of RWC and RA metric requirements, with dynamic profiles, and speed limits for multirotor SUAS, as well as support the definition of flight corridors in the unmanned aircraft system traffic management system.