Evaluating the ellipsoidal collision avoidance region for the future DAA systems

Collision Avoidance is considered as the final layer of safety to prevent mid-air collisions when all other avoidance measures have failed. These methods are gaining importance, in particular in recent years. The ultimate goal is to replace the already obsolete TCAS system, which is not included in the NextGen programme. Additionally, the dynamic UAS market in civil, commercial and military sectors forces development of solutions integrating such systems in the airspace. The steeply increasing numbers of manned and unmanned aerial operations requires safe methods of airspace sharing. This paper analyses ellipsoidal areas, which seem to be an interesting alternative to often proposed, spherical areas. They allow i.e. alarm generation areas to be smaller and the average time from an alarm to a collision to be extended. The proposed methods may be used in DAA (Detect and Avoid) systems which are a subject of standardisation work of various aviation institutions and organisations.