An MAC Probability Assessment Framework for Integrated Operations in Urban Air Mobility Considering Safety Barriers

Risk assessment is a key issue in enabling the increasing use of unmanned aircraft systems (UAS), especially in integrated operational urban airspace. This paper proposes a method to systematically quantify the mid-air collision (MAC) risk for different types of aircraft in urban air mobility (UAM). Specifically, a novel assessment framework is formulated that includes three timelines to track risk evolution for different aircraft (i.e., cooperative, non-cooperative and manned aircraft) and four safety barriers (i.e., procedural, strategic, tactical, and collision avoidance mitigation) to prevent a conflict ending in MAC. Guided by the framework, analytical models are established considering trajectory uncertainty, latency time, and detection and avoidance (DAA) system risk ratio to calculate the failure probability of each barrier, and thus an overall MAC probability. This paper concludes with a real-world case study demonstrating the effectiveness of proposed method. Results show that the cooperative UAS contributes the highest MAC risk in an integrated environment, and the MAC risk posed by manned aircraft spikes when the ownship is approximately 4200 meters from the airport area, while the non-collaborative UAS maintain a consistent minimal MAC risk.