Abstract:

To address the safety issue of future Unmanned Aircraft System (UAS) operating with other aircraft in integrated airspace,this paper proposes a dynamic UAS separation zone model and a risk analysis method.Unlike traditional fixed separation time or distance standards,the dynamic approach aims to ensure operational safety while achieving flexible use of airspace resources.First,a two-layer protection zone based on aircraft dynamic characteristics is established by using the operation performance of the host and the intruder.This includes an outer protection zone covering the aircraft reachable area and an inner protection zone representing aircraft position uncertainties.Second,a wake turbulence threshold model is constructed by considering the relations between induced roll moment from the intruding aircraft and the roll control moment of the host UAS.A comprehensive risk analysis that integrates UAS roll risk and collision risk is specifically conducted.Finally,UAS conflict scenarios including head-on conflicts,crossing conflicts,and rear-end conflicts are simulated and influencing factors such as the speeds of the two aircraft,conflict angles,and initial positions on UAS risk probabilities are analyzed.Results show that the proposed dynamic separation model can reduce UAS-UAS risk probabilities to a relative low level when the values of the outer protection zone,inner protection zone,and wake turbulence are set to 4263m,527m,and 743m,respectively.Besides,though performance analysis in UAS-UAS,manned aircraft-UAS conflict scenarios can provide effective collision avoidance maneuver guidance and benefit UAS safe operation decision-making.

Key words: air transportation, dynamic separation zone, risk analysis, Unmanned Aircraft System (UAS), two-layer protection zone