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    Metropolis II: Benefits of Centralised Separation Management in High-Density Urban Airspace
    (SESAR Joint Undertaking, 2022) Veytia, A.M. ; Badea, C.A. ; Ellerbroek, J. ; Hoekstra, J. ; Patrinopoulou, N. ; Daramouskas, I. ; Lappas, V. ; Kostopoulos, V. ; Vries, V.J.F. de ; Ham, J. van ; Sunil, E. ; Alonso, P.M.P. ; Terrazas, J.R.V. ; Bereziat, D. ; Vidosavljevic, A.
    The Metropolis II project aimed to study the impact of centralised separation management for urban aerial mobility. Three concepts were developed in this study: a fully centralised, strategically separated concept, a hybrid concept featuring centralised strategic separation and distributed tactical separation, and a fully distributed tactical concept. A comparative simulation study was performed, using traffic scenarios based on predicted demand in an urban airspace in the city of Vienna. Simulations were performed with varying traffic densities and situations. Results show that the purely strategic and purely tactical strategies perform comparably in terms of safety, and that further improvements can be achieved with a combination of those strategies.
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    Challenges and new directions for the certification of AI and advanced automation in civil aviation
    (SESAR Joint Undertaking, 2024) Lanzi, P. ; Spiller, E. ; Jameel, M. ; Christoffels, L. ; Gigante, G. ; Esposito, R. ; Contissa, G. ; Sanchi, M. ; Galli, F. ; Everdij, M.H.C. ; Stroeve, S.H.
    This paper examines the certification challenges and opportunities posed by advanced automation and AI-based systems in Air Traffic Management (ATM). The findings presented are the outcome of research carried out in the first part of the SESAR Joint Undertaking's HUCAN project, which aims to develop a holistic, unified certification framework for highly automated systems, addressing both technical reliability and human factors, to ensure their safe and efficient integration into ATM. Based on key issues from ongoing technical and regulatory discussions, the research evaluates current innovative certification approaches and explores how levels of automation can enable a more refined development and certification process. In light of the results obtained, the paper proposes new directions that could advance a holistic approach to certification, considering the guidance provided by EASA.
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    Towards a Digital Control Tower: The Use of Augmented Reality Tools to Innovate Interaction Modes
    (SESAR Joint Undertaking, 2022) Bagassi, S. ; Corsi, M. ; Santarelli, R. ; Teutsch, J. ; Garcia Lasheras, R. ; Amaro Carmona, M.A. ; Groskreutz, A.R.
    This paper describes the EU-funded project “Digital Technologies for Tower” (PJ05-W2 DTT) Solution 97.1 validation exercises by focusing on the simulation platforms and exploited technologies to demonstrate how Virtual/Augmented Reality along with Tracking Labels, Air Gestures and Attention Guidance can allow the air traffic controller to increase head-up time, even in low visibility conditions, to lower the time to react to critical or alerting situations, to reduce the workload, and to improve Situational Awareness and productivity. Important guidelines to further enhance the proposed solutions achieving higher levels of maturity can be drawn starting from the results obtained during the Sol 97.1 validation campaign.
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    Efficient shear layer corrections for acoustics in arbitrary jet flows, Journal of Sound and Vibration
    (Elsevier, 2023) Biesheuvel, J. ; Tuinstra, M. ; Santana, L.D. de ; Venner, C.H.
    Localization of aeroacoustic sound sources in open jet wind tunnel experiments requires an accurate prediction of the acoustic propagation time. Most conventional predictions use either a ray-tracer, coupled with a modelled continuous velocity field, or use ray diffraction and a discretization of the velocity field by means of vortex sheets. In this work a novel method is proposed in which the continuous velocity field is discretized into blocks of constant velocity separated by velocity discontinuities, thus removing the requirement for the velocity to be parallel to the surface that separates the blocks. The acoustic ray is solved by minimization of the acoustic propagation time. The computational effort is low compared to ray-tracing methods while maintaining an improvement in accuracy compared to methodologies using vortex sheets. A specific continuous velocity field is derived that models a self-similar shear layer expanding asymmetrically from a rectangular nozzle. Subsequently, this velocity field is discretized to compute the acoustic rays. Experimental results with a loudspeaker source placed in the open jet of a large industrial wind tunnel showed a decrease in source localization uncertainty compared to techniques based on vortex sheets. This is attributed to the inclusion of the shear layer slanting.
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    Intent-Aware MPC for Aircraft Detect-and-Avoid with Response Delay : A Comparative Study with ACAS Xu
    (EUROCONTROL, 2025) Kordabad, A.B. ; Ghosh, A. ; Soudjani, S. ; Stroeve, S.H.
    In this paper, we propose an intent-aware Model Predictive Control (MPC) approach for the remain-well-clear (RWC) functionality of a multi-agent aircraft detect-and-avoid (DAA) system and compare its performance with the standardized Airborne Collision Avoidance System Xu (ACAS Xu). The aircraft system is modeled as a linear system for horizontal maneuvering, with advisories on the rate of turn as the control input. Both deterministic and stochastic time delays are considered to account for the lag between control guidance issuance and the response of the aircraft. The capability of the MPC scheme in producing an optimal control profile over the entire horizon is used to mitigate the impact of the delay. We compare the proposed MPC method with ACAS Xu using various evaluation metrics, including loss of DAA well-clear percentage, near mid-air collision percentage, horizontal miss distance, and additional flight distance across different encounter scenarios. It is shown that the MPC scheme achieves better evaluation metrics than ACAS Xu for both deterministic and stochastic scenarios.