A Review of Detect and Avoid Standards for Unmanned Aircraft Systems

When operating an unmanned aircraft system within the specific category beyond Air Risk Class a or within the certified category, a detect and avoid system is required in order to mitigate the risk of colliding with manned aircraft. To demonstrate compliance with the regulatory requirements, several standards have been developed which propose a range of technologies and requirements for different operational environments. This paper represents an entry point for understanding the key aspects of this application area. Important concepts, like remain well clear, collision avoidance, and encounter modelling, are elucidated. Furthermore, available standards for detect and avoid systems for unmanned aircraft are presented. The introduced documents are analyzed and summarized with respect to their applicability, their scope, and their major characteristics. Further, a comparison between the standards is given where possible. Some documents describe the system and the corresponding requirements in its entirety, while others focus on equipment and component requirements. Nevertheless, the presented standards are sufficient to cover a wide range of detect and avoid applications. Essential aspects of these standards are listed in a condensed manner, enabling the reader to choose a suitable standard for a given operation.