Prototype Collision-Avoidance System for Small Multirotor Unmanned Aircraft at Low Altitude

Abstract

The increasing number and type of unmanned aircraft system (UAS) operations provide a clear need for safe and efficient integration of UAS into the National Airspace System. The main obstacle in integration is the lack of certified collision avoidance solutions. Traffic Alert and Collision Avoidance System II has limitations to meet the requirements for UASs and has shown to lack the adaptability to future operational environments. The Airborne Collision Avoidance System X (ACAS X) has been developed to address these issues and increase surveillance, alerting, and resolution performance. This research investigates and assesses the performance of a prototype collision avoidance algorithm for low-level application tailored to the unique dynamic capabilities of multirotor small UASs (SUASs) based on the ACAS X framework. These unique capabilities of SUAS platforms allow them to hover, laterally deviate from the flight path, and use speed commands to resolve a conflict with potentially limited maneuvering space. The algorithm supports resolutions for both the horizontal and vertical domains. This paper describes the development and functioning of the prototype system, and it provides insight into the possible tailoring to specific operational and safety requirements for multirotor SUASs.