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A Unified Collision Risk Model for Unmanned Aircraft Systems

This paper proposes a novel risk management framework, and specifically a methodology to model UAS collision risk. The model inherently accounts for the performance of Communication, Navigation and Surveillance (CNS) systems, as well as aircraft vehicle dynamics in evaluating collision risk. The model is applicable to encounters between two or more aircraft, and to terrain collision scenarios. The methodology is underpinned by modelling of the CNS error characteristics, as well as wind uncertainty, and the translation of those characteristics to the spatial domain to form a virtual risk protection volume around each aircraft. The volume is then inflated in proportion to a Target Level of Safety (TLS). The methodology is demonstrated in a simulation case study representative of aircraft-aircraft collision encounters. A 2σ navigation accuracy bound of 185.2 m was found to incur a maximum collision risk of approximately 1.5×10-4 at a separation of 200m.