Development and Evaluation of Test Geometries for Horizontal Daa Guidance

In RTCA DO-365, the Minimum Operational Performance Standards (MOPS) for a UAS Detect and Avoid (DAA) system are specified. In a MOPS compliant DAA system, alerting and guidance is derived from the traffic report that is provided by the DAA tracker. The requirements regarding the content of the traffic report for a DAA system support a first order extrapolation of the reported state of traffic. In case traffic maneuvers, the outcome changes. This may necessitate a change in the magnitude, but in certain situations also the direction of the ownship maneuver that was intended or already being executed to prevent the predicted loss of DAA Well Clear (DWC). Testing DAA guidance should include cases to assess whether information is available that aids the pilot in making a timely decision to reverse the direction of a maneuver. The availability of a set of systematically designed encounter geometries, focused on exploiting weaknesses that result from the first order model underlying DAA guidance and the lack of intent information, can serve as an aid for evaluating and comparing guidance concepts. This paper discusses how such encounter geometries can be designed and used for the evaluation and comparison of DAA horizontal guidance functions.