Systematic specification of conflict geometries for comparison and evaluation of human-in-the-loop Traffic Avoidance functions

A Detect and Avoid capability for Remotely Piloted Aircraft Systems will include a function that enables the remote pilot to remain “well clear” of other airborne traffic; this function is known as Self Separation or Traffic Avoidance. To be able to identify issues related to human information processing and performance, a comparison of data presentation concepts has to include a consideration for encounter complexity. Traditionally, encounter geometries are discussed and specified in terms of geometric properties (e.g. head-on, crossing, overtake and separation at the closest point of approach). To tie the design of encounters that are intended to test alerting concepts closer to the alerting logic used by these concepts, an approach has been used in which the desired encounters are specified in terms of the crossing of alerting thresholds. From these requirements a set of options for the encounter geometries is derived. The concept is illustrated using examples, which have been used to generate encounters during a flight test. Besides being useful for the design of encounters, the real-time depiction of the DCPA profiles proved to be a valuable tool in determining whether an encounter was flown correctly.