Levels of Autonomy for RPAS Detect and Avoid

Key to the widespread operation of remotely piloted aircraft systems in non-segregated airspace is the development and certification of a system for performing detect and avoid (DAA). A comprehensive specification of the DAA sub-functions and an analysis of how these sub-functions can be allocated across the various human-machine elements comprising a remotely piloted aircraft system have yet to be provided in the literature. Such an analysis is also needed to support the definition of levels of autonomy (LoA) for DAA systems (DAAS). This paper presents a framework for defining the functional LoA of DAAS. A high level functional description of a DAAS, drawing on the three-levels of DAA capability defined by ICAO and existing functional specifications available in the literature, is provided. A set of properties relevant to the design and safety-certification of DAAS are identified providing the basis for defining functional LoA for DAA. The particular challenges associated with certifying DAAS of various LoA are discussed.