A large-scale multi-objective flights conflict avoidance approach supporting 4D trajectory operation

Recently, the long-term conflict avoidance approaches based on large-scale flights scheduling have attracted much attention due to their ability to provide solutions from a global point of view. However, the current approaches which focus only on a single objective with the aim of minimizing the total delay and the number of conflicts, cannot provide the controllers with variety of optional solutions, representing different trade-offs. Furthermore, the flight track error is often overlooked in the current research. Therefore, in order to make the model more realistic, in this paper, we formulate the long-term conflict avoidance problem as a multi-objective optimization problem which minimizes the total delay and reduces the number of conflicts simultaneously. As a complex air route networks needs to accommodate thousands of flights, the problem is a large-scale combinatorial optimization problem with tightly coupled variables, which make the problem difficult to deal with. Hence, in order to further improve the searching capability of the solution algorithm, a cooperative co-evolution (CC) algorithm is also introduced to divide the complex problem into several low dimensional sub-problems which are easier to solve. Moreover, a dynamic grouping strategy based on the conflict detection is proposed to improve the optimization efficiency and to avoid premature convergence. The well-known multi-objective evolutionary algorithm based on decomposition (MOEA/D) is then employed to tackle each sub-problem. Computational results using real traffic data from the Chinese air route network demonstrate that the proposed approach obtained better non-dominated solutions in a more effective manner than the existing approaches, including the multi-objective genetic algorithm (MOGA), NSGAII, and MOEA/D. The results also show that our approach provided satisfactory solutions for controllers from a practical point of view

The TASAR Project: Launching Aviation on an Optimized Route Toward Aircraft Autonomy

The Traffic Aware Strategic Aircrew Request (TASAR) concept applies onboard automation for the purpose of advising the pilot of route modifications that would be beneficial to the flight. Leveraging onboard computing platforms with connectivity to avionics and diverse data sources on and off the aircraft, TASAR introduces a new, powerful capability for in-flight trajectory management to the cockpit and its flight crew that is anticipated to induce a significant culture change in airspace operations. Flight crews empowered by TASAR and its derivative technologies could transform from todays flight plan followers to proactive trajectory managers, taking an initial critical step towards increasing autonomy in the airspace system. TASAR was developed as a catalyst for operational autonomy, a future vision where the responsibilities and authorities of trajectory management reside with the aircraft operator and are distributed among participating aircraft, thus fulfilling a vision dating back decades and enabling a fully scalable airspace system. This NASA Technical Paper maps TASAR to its foundational vision and traces its research and development from initial concept generation to an operational evaluation by a U.S. airline in revenue service, the final stage before technology transfer and commercialization

UAS in the Airspace: A Review on Integration, Simulation, Optimization, and Open Challenges

Air transportation is essential for society, and it is increasing gradually due to its importance. To improve the airspace operation, new technologies are under development, such as Unmanned Aircraft Systems (UAS). In fact, in the past few years, there has been a growth in UAS numbers in segregated airspace. However, there is an interest in integrating these aircraft into the National Airspace System (NAS). The UAS is vital to different industries due to its advantages brought to the airspace (e.g., efficiency). Conversely, the relationship between UAS and Air Traffic Control (ATC) needs to be well-defined due to the impacts on ATC capacity these aircraft may present. Throughout the years, this impact may be lower than it is nowadays because the current lack of familiarity in this relationship contributes to higher workload levels. Thereupon, the primary goal of this research is to present a comprehensive review of the advancements in the integration of UAS in the National Airspace System (NAS) from different perspectives. We consider the challenges regarding simulation, final approach, and optimization of problems related to the interoperability of such systems in the airspace. Finally, we identify several open challenges in the field based on the existing state-of-the-art proposals

Contributions to deconfliction advanced U-space services for multiple unmanned aerial systems including field tests validation

Unmanned Aerial Systems (UAS) will become commonplace, the number of UAS flying in European airspace is expected to increase from a few thousand to hundreds of thousands by 2050. To prepare for this approaching, national and international organizations involved in aerial traffic management are now developing new laws and restructuring the airspace to incorporate UAS into civil airspace. The Single European Sky ATM Research considers the development of the U-space, a crucial step to enable the safe, secure, and efficient access of a large set of UAS into airspace. The design, integration, and validation of a set of modules that contribute to our UTM architecture for advanced U-space services are described in this Thesis. With an emphasis on conflict detection and resolution features, the architecture is flexible, modular, and scalable. The UTM is designed to work without the need for human involvement, to achieve U-space required scalability due to the large number of expected operations. However, it recommends actions to the UAS operator since, under current regulations, the operator is accountable for carrying out the recommendations of the UTM. Moreover, our development is based on the Robot Operating System (ROS) and is open source. The main developments of the proposed Thesis are monitoring and tactical deconfliction services, which are in charge of identifying and resolving possible conflicts that arise in the shared airspace of several UAS. By limiting the conflict search to a local search surrounding each waypoint, the proposed conflict detection method aims to improve conflict detection. By splitting the issue down into smaller subproblems with only two waypoints, the conflict resolution method tries to decrease the deviation distance from the initial flight plan. The proposed method for resolving potential threats is based on the premise that UAS can follow trajectories in time and space properly. Therefore, another contribution of the presented Thesis is an UAS 4D trajectory follower that can correct space and temporal deviations while following a given trajectory. Currently, commercial autopilots do not offer this functionality that allows to improve the airspace occupancy using time as an additional dimension. Moreover, the integration of onboard detect and avoid capabilities, as well as the consequences for U-space services are examined in this Thesis. A module capable of detecting large static unexpected obstacles and generating an alternative route to avoid the obstacle online is presented. Finally, the presented UTM architecture has been tested in both software-in-theloop and hardware-in-the-loop development enviroments, but also in real scenarios using unmanned aircraft. These scenarios were designed by selecting the most relevant UAS operation applications, such as the inspection of wind turbines, power lines and precision agriculture, as well as event and forest monitoring. ATLAS and El Arenosillo were the locations of the tests carried out thanks to the European projects SAFEDRONE and GAUSS.Los sistemas aéreos no tripulados (UAS en inglés) se convertirán en algo habitual. Se prevé que el número de UAS que vuelen en el espacio aéreo europeo pase de unos pocos miles a cientos de miles en 2050. Para prepararse para esta aproximación, las organizaciones nacionales e internacionales dedicadas a la gestión del tráfico aéreo están elaborando nuevas leyes y reestructurando el espacio aéreo para incorporar los UAS al espacio aéreo civil. SESAR (del inglés Single European Sky ATM Research) considera el desarrollo de U-space, un paso crucial para permitir el acceso seguro y eficiente de un gran conjunto de UAS al espacio aéreo. En esta Tesis se describe el diseño, la integración y la validación de un conjunto de módulos que contribuyen a nuestra arquitectura UTM (del inglés Unmanned aerial system Traffic Management) para los servicios avanzados del U-space. Con un énfasis en las características de detección y resolución de conflictos, la arquitectura es flexible, modular y escalable. La UTM está diseñada para funcionar sin necesidad de intervención humana, para lograr la escalabilidad requerida por U-space debido al gran número de operaciones previstas. Sin embargo, la UTM únicamente recomienda acciones al operador del UAS ya que, según la normativa vigente, el operador es responsable de las operaciones realizadas. Además, nuestro desarrollo está basado en el Sistema Operativo de Robots (ROS en inglés) y es de código abierto. Los principales desarrollos de la presente Tesis son los servicios de monitorización y evitación de conflictos, que se encargan de identificar y resolver los posibles conflictos que surjan en el espacio aéreo compartido de varios UAS. Limitando la búsqueda de conflictos a una búsqueda local alrededor de cada punto de ruta, el método de detección de conflictos pretende mejorar la detección de conflictos. Al dividir el problema en subproblemas más pequeños con sólo dos puntos de ruta, el método de resolución de conflictos intenta disminuir la distancia de desviación del plan de vuelo inicial. El método de resolución de conflictos propuesto se basa en la premisa de que los UAS pueden seguir las trayectorias en el tiempo y espacio de forma adecuada. Por tanto, otra de las aportaciones de la Tesis presentada es un seguidor de trayectorias 4D de UAS que puede corregir las desviaciones espaciales y temporales mientras sigue una trayectoria determinada. Actualmente, los autopilotos comerciales no ofrecen esta funcionalidad que permite mejorar la ocupación del espacio aéreo utilizando el tiempo como una dimensión adicional. Además, en esta Tesis se examina la capacidad de integración de módulos a bordo de detección y evitación de obstáculos, así como las consecuencias para los servicios de U-space. Se presenta un módulo capaz de detectar grandes obstáculos estáticos inesperados y capaz de generar una ruta alternativa para evitar dicho obstáculo. Por último, la arquitectura UTM presentada ha sido probada en entornos de desarrollo de simulación, pero también en escenarios reales con aeronaves no tripuladas. Estos escenarios se diseñaron seleccionando las aplicaciones de operación de UAS más relevantes, como la inspección de aerogeneradores, líneas eléctricas y agricultura de precisión, así como la monitorización de eventos y bosques. ATLAS y El Arenosillo fueron las sedes de las pruebas realizadas gracias a los proyectos europeos SAFEDRONE y GAUSS

Existing and Required Modeling Capabilities for Evaluating ATM Systems and Concepts

ATM systems throughout the world are entering a period of major transition and change. The combination of important technological developments and of the globalization of the air transportation industry has necessitated a reexamination of some of the fundamental premises of existing Air Traffic Management (ATM) concepts. New ATM concepts have to be examined, concepts that may place more emphasis on: strategic traffic management; planning and control; partial decentralization of decision-making; and added reliance on the aircraft to carry out strategic ATM plans, with ground controllers confined primarily to a monitoring and supervisory role. 'Free Flight' is a case in point. In order to study, evaluate and validate such new concepts, the ATM community will have to rely heavily on models and computer-based tools/utilities, covering a wide range of issues and metrics related to safety, capacity and efficiency. The state of the art in such modeling support is adequate in some respects, but clearly deficient in others. It is the objective of this study to assist in: (1) assessing the strengths and weaknesses of existing fast-time models and tools for the study of ATM systems and concepts and (2) identifying and prioritizing the requirements for the development of additional modeling capabilities in the near future. A three-stage process has been followed to this purpose: 1. Through the analysis of two case studies involving future ATM system scenarios, as well as through expert assessment, modeling capabilities and supporting tools needed for testing and validating future ATM systems and concepts were identified and described. 2. Existing fast-time ATM models and support tools were reviewed and assessed with regard to the degree to which they offer the capabilities identified under Step 1. 3 . The findings of 1 and 2 were combined to draw conclusions about (1) the best capabilities currently existing, (2) the types of concept testing and validation that can be carried out reliably with such existing capabilities and (3) the currently unavailable modeling capabilities that should receive high priority for near-term research and development. It should be emphasized that the study is concerned only with the class of 'fast time' analytical and simulation models. 'Real time' models, that typically involve humans-in-the-loop, comprise another extensive class which is not addressed in this report. However, the relationship between some of the fast-time models reviewed and a few well-known real-time models is identified in several parts of this report and the potential benefits from the combined use of these two classes of models-a very important subject-are discussed in chapters 4 and 7

Multi-objective optimisation of aircraft flight trajectories in the ATM and avionics context

The continuous increase of air transport demand worldwide and the push for a more economically viable and environmentally sustainable aviation are driving significant evolutions of aircraft, airspace and airport systems design and operations. Although extensive research has been performed on the optimisation of aircraft trajectories and very efficient algorithms were widely adopted for the optimisation of vertical flight profiles, it is only in the last few years that higher levels of automation were proposed for integrated flight planning and re-routing functionalities of innovative Communication Navigation and Surveillance/Air Traffic Management (CNS/ATM) and Avionics (CNS+A) systems. In this context, the implementation of additional environmental targets and of multiple operational constraints introduces the need to efficiently deal with multiple objectives as part of the trajectory optimisation algorithm. This article provides a comprehensive review of Multi-Objective Trajectory Optimisation (MOTO) techniques for transport aircraft flight operations, with a special focus on the recent advances introduced in the CNS+A research context. In the first section, a brief introduction is given, together with an overview of the main international research initiatives where this topic has been studied, and the problem statement is provided. The second section introduces the mathematical formulation and the third section reviews the numerical solution techniques, including discretisation and optimisation methods for the specific problem formulated. The fourth section summarises the strategies to articulate the preferences and to select optimal trajectories when multiple conflicting objectives are introduced. The fifth section introduces a number of models defining the optimality criteria and constraints typically adopted in MOTO studies, including fuel consumption, air pollutant and noise emissions, operational costs, condensation trails, airspace and airport operations

Autonomous Flight Rules - A Concept for Self-Separation in U.S. Domestic Airspace

Autonomous Flight Rules (AFR) are proposed as a new set of operating regulations in which aircraft navigate on tracks of their choice while self-separating from traffic and weather. AFR would exist alongside Instrument and Visual Flight Rules (IFR and VFR) as one of three available flight options for any appropriately trained and qualified operator with the necessary certified equipment. Historically, ground-based separation services evolved by necessity as aircraft began operating in the clouds and were unable to see each other. Today, technologies for global navigation, airborne surveillance, and onboard computing enable the functions of traffic conflict management to be fully integrated with navigation procedures onboard the aircraft. By self-separating, aircraft can operate with more flexibility and fewer restrictions than are required when using ground-based separation. The AFR concept is described in detail and provides practical means by which self-separating aircraft could share the same airspace as IFR and VFR aircraft without disrupting the ongoing processes of Air Traffic Control

3D-in-2D Displays for ATC.

This paper reports on the efforts and accomplishments of the 3D-in-2D Displays for ATC project at the end of Year 1. We describe the invention of 10 novel 3D/2D visualisations that were mostly implemented in the Augmented Reality ARToolkit. These prototype implementations of visualisation and interaction elements can be viewed on the accompanying video. We have identified six candidate design concepts which we will further research and develop. These designs correspond with the early feasibility studies stage of maturity as defined by the NASA Technology Readiness Level framework. We developed the Combination Display Framework from a review of the literature, and used it for analysing display designs in terms of display technique used and how they are combined. The insights we gained from this framework then guided our inventions and the human-centered innovation process we use to iteratively invent. Our designs are based on an understanding of user work practices. We also developed a simple ATC simulator that we used for rapid experimentation and evaluation of design ideas. We expect that if this project continues, the effort in Year 2 and 3 will be focus on maturing the concepts and employment in a operational laboratory settings

Engage D5.6 Thematic challenge briefing notes (1st and 2nd releases)

Engage identified four thematic challenges to address research topics not contemporaneously (sufficiently) addressed by SESAR. This deliverable serves primarily as a record of the two sets of released thematic challenge briefing notes

A Concept for Robust, High Density Terminal Air Traffic Operations

This paper describes a concept for future high-density, terminal air traffic operations that has been developed by interpreting the Joint Planning and Development Office s vision for the Next Generation (NextGen) Air Transportation System and coupling it with emergent NASA and other technologies and procedures during the NextGen timeframe. The concept described in this paper includes five core capabilities: 1) Extended Terminal Area Routing, 2) Precision Scheduling Along Routes, 3) Merging and Spacing, 4) Tactical Separation, and 5) Off-Nominal Recovery. Gradual changes are introduced to the National Airspace System (NAS) by phased enhancements to the core capabilities in the form of increased levels of automation and decision support as well as targeted task delegation. NASA will be evaluating these conceptual technological enhancements in a series of human-in-the-loop simulations and will accelerate development of the most promising capabilities in cooperation with the FAA through the Efficient Flows Into Congested Airspace Research Transition Team