An introduction to ACAS Xu and the challenges ahead

Manfredi, Guido; Jestin, Yannick

doi:10.1109/dasc.2016.7778055

Cited by 61 publications

(40 citation statements)

References 9 publications

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“…Class III DAA systems will utilize the next-generation Airborne Collision Avoidance System (ACAS X), the expected successor to TCAS II. A particular variant of ACAS X -ACAS XU -is designed for vehicles with unique surveillance and performance characteristics, such as UAS [19]. ACAS XU is optimizable and can be configured to perform both the DAA and Collision Avoidance functions, bypassing the need for an interoperability schema as is required for Class II systems.…”

Section: Discussionmentioning

confidence: 99%

An Interoperability Concept for Detect and Avoid and Collision Avoidance Systems: Results from a Human-in-the-Loop Simulation

Rorie

Fern

2018

2018 Aviation Technology, Integration, and Operations Conference

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The integration of Unmanned Aircraft Systems (UAS) into the National Airspace System (NAS) poses a variety of technical challenges to UAS developers and aviation regulators. In response to growing demand for access to civil airspace in the United States, the Federal Aviation Administration (FAA) has produced a roadmap identifying key areas requiring further research and development. One such technical challenge is the development of a "detect and avoid" system (DAA) capable of providing a means of compliance with the "see and avoid" requirement in manned aviation. The purpose of the DAA system is to support the pilot, situated at a ground control station (GCS), in maintaining "DAA well clear" of nearby aircraft through the use of GCS displays and alerts. In addition to its primary function of aiding the pilot in maintaining DAA well clear, the DAA system must also safely interoperate with existing NAS systems and operations, such as the airspace management procedures of air traffic controllers (ATC) and Collision Avoidance (CA) systems currently in use by manned aircraft, namely the Traffic Alert and Collision Avoidance System (TCAS II). It is anticipated that many UAS architectures will integrate both a DAA system and a TCAS II. It is therefore necessary to explicitly study the integration of DAA and TCAS II alerting structures and maneuver guidance formats to ensure that pilots understand the appropriate type and urgency of their response to the various alerts. This paper presents a concept of interoperability for the two systems. The concept was developed with the goal of avoiding any negative impact on the performance level of TCAS II while retaining a DAA system that still effectively enables pilots to maintain DAA well clear. The interoperability concept described in the paper focuses primarily on facilitating the transition from a latestage DAA encounter (where a loss of DAA well clear is imminent) to a TCAS II Corrective Resolution Advisory (RA), which requires pilot compliance within five seconds of its issuance. The interoperability concept was presented to 10 participants (6 active UAS pilots and 4 active commercial pilots) in a medium-fidelity, human-in-the-loop simulation designed to stress different aspects of the DAA and TCAS II systems. Pilots' ability to maintain separation, their rate of compliance and response times using the interoperability concept are reported. Results indicated that pilots exhibited comprehension of, and appropriate prioritization within, the DAA-TCAS II combined alert structure. Pilots demonstrated a high rate of compliance with TCAS II RAs and were also seen to respond to corrective RAs within the five second requirement established for manned aircraft. The DAA system presented under test was also shown to be effective in supporting pilots' ability to maintain DAA well clear in the overwhelming majority of cases in which pilots had sufficient time to respond.

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Section: Discussionmentioning

confidence: 99%

An Interoperability Concept for Detect and Avoid and Collision Avoidance Systems: Results from a Human-in-the-Loop Simulation

Rorie

Fern

2018

2018 Aviation Technology, Integration, and Operations Conference

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“…Further, since there is a wide variety of sUAS, many different dynamic models would need to be implemented. 6 At the time of this writing, the FAA does not yet offer any standards for operating small UASs autonomously or beyond visual line of sight (BVLOS).…”

Section: Requirements For An Effective Saa Systemmentioning

confidence: 99%

Sense and avoid for small unmanned aircraft systems: Research on methods and best practices

Skowron

Chmielowiec

Glowacka

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part G:

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In this study, we discuss recent advances and state-of-the-art sense-and-avoid solutions for small unmanned aircraft systems. The purpose of this paper is to equip the reader with the most up-to-date information on research and commercial efforts aimed at introducing autonomous small unmanned aircraft systems into the shared airspace. We present a broad overview of the regulatory environment, current abilities, and limitations of various sensor types as well as algorithmic and computational aspects of establishing a reliable sense-and-avoid platform. This paper reviews a substantial portion of the literature, focusing on developing reliable sense-and-avoid systems. It brings together information from various sources, including commercial drone and sensor manufacturers, regulatory agencies, as well as basic research performed in this regard. While academic and industrial research activities aimed at developing an effective sense-and-avoid system for small unmanned aircraft systems are intensifying, the current technology does not yet allow for a comprehensive solution that would enable autonomous flight. However, recent advances in hardware miniaturization, increases in computational power, and new algorithmic solutions allow us to remain optimistic about future developments.

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“…Its definition contains two particular variations: ACAS Xa for large aircraft, and ACAS Xu for unmanned aircraft. The work in [23] describes the specificities and challenges to the ACAS Xu system.…”

Section: Related Workmentioning

confidence: 99%

Architectural design of a Safe Mission Manager for Unmanned Aircraft Systems

Usach

Vila

Torens

et al. 2018

Journal of Systems Architecture

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Civil Aviation Authorities are elaborating a new regulatory framework for the safe operation of Unmanned Aircraft Systems (UAS). Current proposals are based on the analysis of the specific risks of the operation as well as on the definition of some risk mitigation measures. In order to achieve the target level of safety, we propose increasing the level of automation by providing the onboard system with Automated Contingency Management functions. The aim of the resulting Safe Mission Manager System is to autonomously adapt to contingency events while still achieving mission objectives through the degradation of mission performance. In this paper, we discuss some of the architectural issues in designing this system. The resulting architecture makes a conceptual differentiation between event monitoring, decision-making on a policy for dealing with contingencies and the execution of the corresponding policy. We also discuss how to allocate the different Safe Mission Manager components to a partitioned, Integrated Modular Avionics architecture. Finally, determinism and predictability are key aspects in contingency management due to their overall impact on safety. For this reason, we model and verify the correctness of a contingency management policy using formal methods.

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An introduction to ACAS Xu and the challenges ahead

Cited by 61 publications

References 9 publications

An Interoperability Concept for Detect and Avoid and Collision Avoidance Systems: Results from a Human-in-the-Loop Simulation

An Interoperability Concept for Detect and Avoid and Collision Avoidance Systems: Results from a Human-in-the-Loop Simulation

Sense and avoid for small unmanned aircraft systems: Research on methods and best practices

Architectural design of a Safe Mission Manager for Unmanned Aircraft Systems

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