Modeling and simulation of intrinsic uncertainties in validation of collision avoidance systems

Sybert H. Stroeve, Henk A.P. Blom, Carlos Hernandez Medel, Carlos Garcia Daroca, Alvaro Arroyo Cebeira, Stanislaw Drozdowski

Research output: Contribution to journalArticleScientificpeer-review

28 Downloads (Pure)


Airborne collision avoidance systems (ACASs) form a key safety barrier by providing last-moment resolution advisories (RAs) to pilots for avoiding midair collisions. Intrinsic uncertainties, such as noise in ACAS input signals and variability in pilot performance, imply that the generation of RAs and the effectuated aircraft trajectories are nondeterministic processes. Existing ACAS validation methods reflect the intrinsic uncertainties to a limited extent only. This paper develops an agent-based model, which systematically captures uncertainties in ACAS input and pilot performance for Monte Carlo (MC) simulation of encounter scenarios. The agent-based model has been integrated with industry-specific implementations of Traffic Alert and Collision Avoidance System II and ACAS Xa in a novel collision avoidance validation and evaluation tool. Through illustrative MC simulation results, it is demonstrated that the intrinsic uncertainties can have a significant effect on the variability in timing and types of RAs, and subsequently on the variability in miss distance. Even the MC simulation estimated mean miss distance can differ significantly from the deterministically simulated miss distance. Most important, the tails of miss distance probability distributions and probabilities of near-midair collisions are affected. This stipulates that addressing intrinsic uncertainties through MC simulation is essential in evaluating ACASs.

Original languageEnglish
Pages (from-to)173-183
Number of pages11
JournalJournal of Air Transportation
Issue number4
Publication statusPublished - 2020


Dive into the research topics of 'Modeling and simulation of intrinsic uncertainties in validation of collision avoidance systems'. Together they form a unique fingerprint.

Cite this