Three-dimensional conflict count models for unstructured and layered airspace designs

Abstract

This paper presents analytical models that describe the safety of unstructured and layered en route airspace designs. Here, 'unstructured airspace' refers to airspace designs that offer operators complete freedom in path planning, whereas 'layered airspace' refers to airspace concepts that utilize heading-altitude rules to vertically separate cruising aircraft based on their travel directions. With a focus on the intrinsic safety provided by an airspace design, the models compute instantaneous conflict counts as a function of traffic demand and airspace design parameters, such as traffic separation requirements and the permitted heading range per flight level. While previous studies have focused primarily on conflicts between cruising aircraft, the models presented here also take into account conflicts involving climbing and descending traffic. Fast-time simulation experiments used to validate the modeling approach indicate that the models estimate instantaneous conflict counts with high accuracy for both airspace designs. The simulation results also show that climbing and descending traffic caused the majority of conflicts for layered airspaces with a narrow heading range per flight level, highlighting the importance of including all aircraft flight phases for a comprehensive safety analysis. Because such trends could be accurately predicted by the three-dimensional models derived here, these analytical models can be used as tools for airspace design applications as they provide a detailed understanding of the relationships between the parameters that influence the safety of unstructured and layered airspace designs.

Review of Conflict Resolution Methods for Manned and Unmanned Aviation

“…For resolving short-term conflicts, climb/descend is a fast and efficient action since the required vertical separation is smaller than the horizontal one. Sunil [49] showed that for a stratified airspace, having only horizontal resolutions improves stability; less conflicts are considered and accounted for with only an horizontal conflict layer. Not including vertical changes is also acceptable from a performance point of view, as the latter is highly affected by the flight level the aircraft is operating in.…”

RPAS integration in non-segregated airspace: Safety metrics for tactical planning

“…The introduction of the aircraft climbing or descending does not imply any complexity except the development of new trajectories modifying the cinematic equations. [31][32][33] Moreover, we do not consider uncertainty associated with the aircraft velocity or the positioning because it is not considered a probabilistic study of conflict risk.…”

Design of an ATC Tool for Conflict Detection Based on Machine Learning Techniques

“…His work was paramount because it settled the pillars of collision risk based on random flight errors (positioning and velocity). Other authors have employed more or less complex techniques to evaluate collision and conflict risk [7][8][9][10][11]. The authors recommend the work of Netjasov and Janic [12] for a deeper review of CRM.…”