Safety Assessment of a UAV CD&R System in High Density Airspace Using Monte Carlo Simulations

This paper presents a safety assessment method for unmanned aerial vehicle (UAV) operations, including the effect of a distributed conflict detection and resolution (CD&R) system, in a high density airspace environment. Here, the expected conflicts occurrence and chances for each CD&R system to perform are sufficiently high to extract two parameters of safety, i.e., the frequency of near mid-air collision (NMAC) and the frequency of mid-air collision (MAC), by series of Monte Carlo simulations. The results are then used to derive the safety parameters in a more realistic, less dense airspace. Two cases of distributed CD&R protocols are assessed and compared, i.e., 1) uncoordinated protocol, where each vehicle has its own avoidance preferences, and 2) implicitly coordinated protocol where each vehicle, while still independent from each other, applies simple common rules. Using those CD&R protocols, the result shows a reduction of more than 94% of possible NMAC. Moreover, while maintaining the target level of safety in the airspace, the maximum number of UAVs under an implicitly coordinated CD&R protocol can be at least ten times more than cases when no CD&R is applied.