Modeling Airspace Stability and Capacity for Decentralized Separation

In the context of decentralized separation, airspace stability pertains to the propagation of con?ict chain reactions as a result of tactical con?ict resolution maneuvers. This notion of airspace stability has been used in previous literature to develop a semi-empirical method for determining the capacity of a decentralized direct-routing airspace concept in the horizontal plane. The present paper extends this method by explicitly mod-eling: a) the effect of a given Con?ict Detection and Resolution (CD&R) strategy on the stability of the airspace; b) the in?uence of direct-routing on instantaneous con?ict probability; and c) the impact of ?nite-time measurements on the determination of airspace states. To validate the resulting analytical capacity model, fast-time simulations were performed. The results indicate that the predictions of the analytical model are close to that of the previous semi-empirical approach. Thus, the analytical model can be used to obtain a ?rst-order estimate of the maximum theoretical capacity, as along as simulation settings do not cause the ‘local’, or per aircraft, con?ict rate to deviate signi?cantly from assumptions made during the model derivation. Future work will focus on relaxing model assumptions, and extending the modeling approach to three-dimensional airspace.