Air Traffic Control System Research Articles

Метод багатокритеріального розв’язання конфліктної ситуації між двома повітряними суднами у тривимірному просторі на основі динамічного програмування

Мета: Глобальні тенденції зростання інтенсивності повітряного руху обумовлюють збільшення кількості конфліктних ситуацій між повітряними судами. Актуальною проблемою є розробка нових методів розв’язання конфліктних ситуацій, які повинні забезпечувати синтез безконфліктних траєкторій у тривимірному просторі у відповідності до різних критеріїв ефективності польотів. Методи: Розроблено метод багатокритеріального розв’язання конфліктної ситуації між двома повітряними суднами із застосуванням маневрування зміною курсу, швидкості та висоти польоту. Описаний метод на основі динамічного програмування забезпечує синтез оптимальної безконфліктної траєкторії відповідно до критеріїв регулярності, економічності польотів та складності маневрування. Наведено рівняння багатокритеріального динамічного програмування для визначення множини Парето-оптимальних оцінок безконфліктних траєкторій у неперервній та дискретній формі. Синтез Парето-оптимальних безконфліктних траєкторій здійснюється із застосуванням прямої процедури дискретного багатокритеріального динамічного програмування. Моделювання траєкторій польоту виконується із використанням спеціальної моделі керованого руху повітряного судна. Вибір оптимальної безконфліктної траєкторії з множини Парето-оптимальних виконується із застосуванням згортки критеріїв оптимальності. В рамках методу визначено наступні процедури: прогнозування порушень мінімумів ешелонування; дискретизації станів та керувань, інтерполяції оцінок ефективності траєкторій за встановленими критеріями оптимальності. Результати: Дослідження запропонованого методу виконано шляхом комп’ютерного моделювання, результати якого показали, що розрахована оптимальна безконфліктна траєкторія забезпечує усунення конфліктної ситуації та відповідає встановленим критеріям оптимальності. Обговорення: Основними перевагами методу є: застосування маневрів по зміні курсу, швидкості та висоти польоту для усунення конфлікту; багатокритеріальна оптимізація безконфліктних траєкторій; застосування динамічного програмування, що підвищує обчислювальну ефективність. Запропонований метод може бути використаний при розробці засобів розв’язання конфліктних ситуацій для автоматизованих систем управління повітряним рухом.

Integrating Drones into the Us Air Traffic Control System

The technology already exists to build drones that are able to electronically see and avoid other aircraft. Drones of all sizes can be integrated into the air traffic control system by using this technology and maintaining the current requirement that drones yield the right-of-way to other aircraft. This technology is already used in piloted aircraft, and examining how drones can be integrated into the air traffic control system suggests ways that the system can be improved for piloted aircraft as well. The current system is a centralized system in which aircraft follow the instructions given by air traffic controllers. Current technology would allow a redesign so that both piloted and unmanned aircraft could fly when and where they want. Such a system would resolve potential conflicts in a decentralized manner as they arise, without the need for centralized control of air traffic.

Trajectory Specification for Terminal Air Traffic: Arrival Spacing

“Trajectory specification” is the explicit bounding and control of aircraft trajectories such that the position at each point in time is constrained to a precisely defined volume of space. The bounding space is defined by cross-track, along-track, and vertical tolerances relative to a reference trajectory that specifies position as a function of time. The tolerances are dynamic and are based on the aircraft navigation capabilities and the current traffic situation. A standard language will be developed to represent these specifications and to communicate them by datalink. Assuming conformance, trajectory specification can guarantee safe separation for an arbitrary period of time, even in the event of an air traffic control system or datalink failure; hence, it can help to achieve the high level of safety and reliability needed for air traffic control automation. As a more proactive form of air traffic control, it can also maximize airspace capacity and reduce the reliance on tactical backup systems during normal operation. It applies to both en route airspace and the terminal area around airports, but this paper focuses on arrival spacing in the terminal area and presents algorithms and software for achieving a specified delay of runway arrival time.

The impact of alerting design on air traffic controllers' response to conflict detection and resolution

Purposes: The research aim is to develop a better design of auditory alerts that can improve air traffic controllers' situation awareness. MethodParticipants are seventy-seven qualified Air Traffic Controllers. The experiment was conducted in the Air Traffic Control operational rooms of the Irish Aviation Authority at Shannon and Dublin. Participants were advised that the trials were in relation to the Operational Air Traffic Control system. ANOVA with two between-subject factors (alerting designs and experience levels) were conducted to analyze the ATCO's response time for three critical events. Bonferroni test was performed for post-hoc analysis on mean differences of response time. ResultsThere is a significant difference in ATCO's response time between acoustic alert and semantic alert across STCA, APW and MSAW. No significant main effect of controllers' experience on ATCO's response time for STCA and APW. Also, there is no significant interaction between alerting design and experience level on ATCO's response time across STCA, APW and MSAW. ConclusionThe results demonstrated that the acoustic alert deployed within the ATM system provides level-1 Situational Awareness to ATCO's compared with an semantic alert which provides not only level-1 of situational awareness for perceived alerts, but also level-2 and level-3 of situational awareness to assist ATCO understanding of critical events and therefore develop more suitable solutions. Consequently, human-centered design of a semantic alert can significantly speed up ATCO's response to STCA, and APW. Furthermore, the semantic alert could alleviate expertise differences by promoting quicker response times for both novice and experienced air traffic controllers.

Future-based Static Analysis of Message Passing Programs

Message passing is widely used in industry to develop programs consisting of several distributed communicating components. Developing functionally correct message passing software is very challenging due to the concurrent nature of message exchanges. Nonetheless, many safety-critical applications rely on the message passing paradigm, including air traffic control systems and emergency services, which makes proving their correctness crucial. We focus on the modular verification of MPI programs by statically verifying concrete Java code. We use separation logic to reason about local correctness and define abstractions of the communication protocol in the process algebra used by mCRL2. We call these abstractions futures as they predict how components will interact during program execution. We establish a provable link between futures and program code and analyse the abstract futures via model checking to prove global correctness. Finally, we verify a leader election protocol to demonstrate our approach.

A novel approach to manage cloud security SLA incidents

Cloud computing is increasingly playing an important role in the service provisioning domain given the economic and technological benefits it offers. The popularity of cloud services is increasing but so are their customers’ concerns about security assurance and transparency of the Cloud Service Providers (CSPs). This is especially relevant in the case of critical services that are progressively moving to the cloud. Examples include the integrated European air traffic control system or public administrations through the governmental clouds. Recent efforts aim to specify security in cloud by using security service level agreements (secSLAs). However, the paucity of approaches to actually control the fulfillment of secSLAs and to react in case of security breaches, often results in distrust in cloud services. In this paper, we present a solution to monitor and enforce the fulfillment of secSLAs. Our framework is able to (a) detect occurrences that lead to unfulfillment of commitments, and (b) also provide mitigation to the harmful events that may or do compromise the validity of secSLAs.

Scheduling models for optimal aircraft traffic control at busy airports: Tardiness, priorities, equity and violations considerations

This work addresses the real-time optimization of take-off and landing operations at a busy terminal control area in case of traffic congestion. Terminal areas are becoming the bottleneck of the entire air traffic control system, in particular in the major European airports, where there is a limited possibility to build new infrastructure. The real-time problem of effectively managing aircraft operations is particularly challenging, since it is necessary to incorporate the safety regulations into the optimization model and to consider numerous performance indicators that are important to compute good quality solutions. However, in practice there is no well-recognized objective function and traffic controllers often use simple scheduling rules. In this paper, mixed integer linear programming formulations are proposed to investigate the trade-off between various performance indicators of practical interest, while taking into account the safety constraints with a high modeling precision. Experiments are performed for the two major Italian airports, Milano Malpensa and Roma Fiumicino, by simulating various sets of random landing and take-off aircraft disturbances. Practical-size instances are solved to (near)optimality via a commercial solver. The optimized solutions are also compared with a commonly used scheduling rule. A comprehensive computational analysis makes possible the selection of those solutions that are able to find a good compromise among the various indicators and, consequently, the investigation of the most representative formulation.

Procuring commercial-off-the-shelf software for Air Traffic Services systems in state-owned organizations: A client-centered case study in Spain

This paper reports preliminary findings of a client-centered exploratory study on how Commercial Off-The-Shelf (COTS) software influences the procurement of Air Traffic Services (ATS) systems in state-owned organizations. Our work carried out an initial qualitative study on the case of the Spanish Automated Air Traffic Control System (SACTA) in ENAIRE, the national Air Navigation Services Provider (ANSP). As a result, we present an tentative model of the case where a series of emerging ideas is identified. These ideas constitute a client-centered conceptual framework that may help state-owned organizations understand some phenomena associated to the evaluation and procurement of COTS-based ATS systems.

Formal specification and analysis of take-off procedure using VDM-SL

Abstract Purpose Air traffic management system is a complex adaptive and safety critical system which requires considerable attention for its modelling and verification. Currently Air traffic control (ATC) systems are heavily dependent upon human intervention at airport causing accidents and delays because of failure of communication. The purpose of this study is to develop, plan, manage and verify aircrafts movement procedures at the airport surface that prevent delays and collisions. Methods The airport surface is decomposed into blocks and represented by the graph relation. The state space of the system is described by identifying all the possible components of the system. The ground and local controls monitor queues of the aircrafts moving from taxiway to take-off. It is insured that once an aircraft is inserted into a queue, it is eventually removed from it after the next queue has become available. The take-off procedure is provided using graph theory and Vienna Development Method Specification Language (VDM-SL) and analyzed using VDM-SL toolbox. Results Formal specification of graph-based model, taxiways, aircrafts, runways and controllers is provided in static part of the model. The state space analysis describing take-off algorithms is provided by defining optimal paths and possible operations in dynamic model expediting the departure procedure. The model is developed by a series of refinements following the stepwise development approach. Conclusions The delays at airport surface require effective safety and guidance protocols to control air traffic at the airport. In static model, the safety criteria are described in terms of invariants over the data types carrying critical information. The safety is insured by defining pre/post conditions in description of operations for changing state space of the system. Although the proposed study is focussed more on the safety component, however, the efficiency is not ignored.

Sector-based Distributed Scheduling Strategy in Air Traffic Flow Management

Abstract: Air traffic flow scheduling is an important component in air traffic control system and has significant effects on the safety and efficiency of air transportation. In this paper, we propose a sector-based distributed air traffic flow scheduling strategy to minimize the airport arrival delay. The scheduling problem is formulated based on a simplified air traffic system model consisting of sectors, air-routes, waypoints and airports. A cell transmission flow dynamic model is adopted to describe the system dynamics and some safety-based constraints such as the sequence of en-routed aircraft and the limitations of cruising speeds are considered in the system model. To overcome the computational complexity involved in the centralized structure, we propose a sector-based distributed approach based on Lagrangian relaxation. Experimental results demonstrate the effectiveness of the proposed scheduling strategies.

Strategic Deconfliction of 4D Trajectory and Perturbation Analysis for Air Traffic Control and Automation System

Strategic 4D trajectory conflict-free planning is recognized as one of the core technologies of next-generation air traffic control and automation systems. To resolve potential conflicts during strategic 4D conflict-free trajectory planning, a protection-zone conflict-control model based on air traffic control separation constraints was proposed, in which relationships between expected arrival time and adjusted arrival time at conflicting waypoints for aircraft queues were built and transformed into dynamic linear equations under the definition of max-plus algebra. A method for strategic deconfliction of 4D trajectory was then proposed using two strategies: arrival time adjustment and departure time adjustment. In addition, departure time and flight duration perturbations were introduced to analyze the sensitivity of the planned strategic conflict-free 4D trajectories, and a robustness index for the conflict-free 4D trajectories was calculated. Finally, the proposed method was tested for the Shanghai air traffic control terminal area. The outcomes demonstrated that the planned strategic conflict-free 4D trajectories could avoid potential conflicts, and the slack time could be used to indicate their robustness. Complexity analysis demonstrated that deconfliction using max-plus algebra is more suitable for deconfliction of 4D trajectory with random sampling period in fix air route.

Synthesis of Remote Air Traffic Control System and Air Traffic Controllers’ Perceptions

Airports face financial constraints in the use of services of air traffic control (ATC) towers. The remote air traffic control system (RATCS) is anticipated to be an economical and safe alternative to a control tower. RATCS is a concept intended to supply ATC to an airport by providing communication, navigation, and surveillance from a remote location. This study aims to gain insights about RATCS by conducting a review of existing studies, airport visits, discussions with RATCS technology providers, RATCS demonstration visits, and questionnaire surveys and interviews of controllers. A major inference from nontowered airport visits is that the introduction of RATCS will present many challenges such as pilot readiness to be supervised by RATCS, differences in local conditions, and significant limitations in available infrastructure. The knowledge gained through airport–demonstration visits and meetings with RATCS providers assisted in designing a questionnaire survey and interview. The number of surveys and interviews was limited; hence, conducting a comprehensive quantitative evaluation from responses was difficult. Nevertheless, controllers who participated in the study developed a consensus. The survey outcomes showed that controllers had concerns about RATCS functionality for communication or coordination between controllers and for ATC in high traffic conditions. The controllers provided favorable responses toward new features of RATCS, such as infrared cameras, high-definition monitors, target tracking functionality, and runway overlays. Potential advantages of RATCS anticipated by some controllers include systems with replay capabilities, situational awareness capabilities in low-visibility conditions, and surveillance capabilities of ground operations.

Quantifying the Effects of Uncertainty in a Decentralized National Airspace System

Modernization of the National Air Traffic Control System is on the horizon and with it the likely introduction of autonomous air vehicles into the national airspace. With the increase in air traffic to an already congested management scheme, the implementation of a decentralized control protocol may be the answer to replace the current classical centralized management system. Equipping each aircraft with the information necessary to navigate safely through integrated airspace becomes an information-sharing problem: How much information about other aircraft is required for a pilot to fly the gamut of a heavily populated airspace safely? What paradigm shifts may be necessary for safe and efficient use of available airspace? This paper describes the development of a tool for testing alternative traffic management systems—centralized and decentralized—in the presence of uncertainty. Applying a computational fluid dynamics–inspired approach to the problem both creates a simulation tool to model the movement of traffic within the airspace and allows study of the effects of interactions between vehicles. With incorporation of a model based on smoothed particle hydrodynamics, discrete particle aircraft each carry a set of unique deterministic and stochastic properties. With this model, aircraft interaction can be studied for better understanding of how variations in the nondeterministic properties of the system affect its overall efficiency and safety. The tool is structured to be sufficiently flexible to allow incorporation of different governing equations (right-of-way rules) for aircraft traffic management.

Multiobjective Simulated Annealing for Collision Avoidance in ATM Accounting for Three Admissible Maneuvers

Technological advances are required to accommodate air traffic control systems for the future growth of air traffic. Particularly, detection and resolution of conflicts between aircrafts is a problem that has attracted much attention in the last decade becoming vital to improve the safety standards in free flight unstructured environments. We propose using the archive simulated annealing-based multiobjective optimization algorithm to deal with such a problem, accounting for three admissible maneuvers (velocity, turn, and altitude changes) in a multiobjective context. The minimization of the maneuver number and magnitude, time delays, or deviations in the leaving points are considered for analysis. The optimal values for the algorithm parameter set are identified in the more complex instance in which all aircrafts have conflicts between each other accounting for 5, 10, and 20 aircrafts. Moreover, the performance of the proposed approach is analyzed by means of a comparison with the Pareto front, computed using brute force for 5 aircrafts and the algorithm is also illustrated with a random instance with 20 aircrafts.

Real time Hough transform based track initiators in clutter

In both military and civilian surveillance systems such as Air Traffic Control (ATC) systems, tracking targets in clutter using radar involves dealing with a number of challenges, all related to real time decision and data fusion theories. A major challenge is to detect the real targets through the received measurements in real time and to activate the tracking process.This paper deals with real time automatic initiation of tracks in clutter. Among the proposed solutions in the literature to handle this problem, the conventional Hough transforms (HT) and the Modified Hough Transforms (MHT) have been shown to be effective as track initiator techniques in dense clutter. However, these techniques are computationally intensive. Inasmuch as the tracking of targets is a real time application, we propose in this work, to modify both the Hough transforms (HT) and the Modified Hough Transforms (MHT) so that they can work in real time in adverse environments. The resulting techniques are called Real Time HT (RTHT) and Real Time MHT (RTMHT). Monte Carlo simulations are used to assess the performance of the proposed techniques.

시뮬레이션을 활용한 ADS-B와 TCAS의 탐지 성능 비교

TCAS (traffic alert and collision avoidance system)의 성능 향상을 위해서는 각종정보를 송신해주는 센서의 성능이 향상되어야 한다. 본 논문에서는 성능향상을 위해 기존에 사용 중인 레이더와 같은 센서를 대신하여 차세대 항공관제시스템인 ADS-B (automatic dependent surveillance-broadcast)를 적용하였다. 또한 ADS-B에서 초정밀 GPS (global positioning system) 보정시스템인 SBAS (satellite based augmentation system)의 정보를 사용하여 향상된 위치정확도를 TCAS에 적용할 수 있을 것이라 가정하고 TCAS와 ADS-B를 분석하였다. 시뮬레이션을 해본 결과, 이러한 ADS-B의 도움을 받는 TCAS 장비는 사전에 항공기의 위치를 파악하여 CPA (closest ponit of approach)를 계산할 수 있고 불필요한 RA (resolution advisory) 동작을 감소시킬 수 있다는 것이 확인되었고, 또한 조종사의 업무로드 감소와 불필요한 RA동작이 줄어듦에 따른 연료소비나 시간 등에 대한 장점이 있음이 확인되었다. In order to improve the performance of TCAS it should improve the performance of the sensor, which transmits a variety of information. In this paper, To improve the performance of the existing radar sensors such as being used in behalf of the next generation air traffic control system, ads-b the applied. In addition, ADS-B in a high precision by using information from the correction GPS system, SBAS assume would be able to apply an improved location accuracy for TCAS and analyzed TCAS and ADS-B. Played the simulation results, TCAS equipment receives the help of these ADS-B can calculate a CPA to determine the position of the aircraft in advance, and it was confirmed that it is possible to reduce the unnecessary RA operation, also, the pilot reduction and the workload, it has advantages such as fuel consumption and time associated with the reduced operation unnecessary RA was confirmed.

ОСОБЕННОСТИ ФОРМИРОВАНИЯ УТОМЛЕНИЯ В ДНЕВНЫЕ И НОЧНЫЕ 12-ЧАСОВЫЕ СМЕНЫ У ИНЖЕНЕРОВ АВТОМАТИЗИРОВАННЫХ СИСТЕМ УПРАВЛЕНИЯ ВОЗДУШНЫМ ДВИЖЕНИЕМ

ОСОБЕННОСТИ ФОРМИРОВАНИЯ УТОМЛЕНИЯ В ДНЕВНЫЕ И НОЧНЫЕ 12-ЧАСОВЫЕ СМЕНЫ У ИНЖЕНЕРОВ АВТОМАТИЗИРОВАННЫХ СИСТЕМ УПРАВЛЕНИЯ ВОЗДУШНЫМ ДВИЖЕНИЕМ

Assuring safety in air traffic control systems with argumentation and model checking

Although the continuous safety technology advances in fields like air traffic control (ATC) systems or medical devices, the crux of safety assurance still comes down to human decision makers, which, within the context of having to define priorities while simultaneously considering different contextual criteria, present a constant high risk of erroneous decisions. We illustrate in this article a recommender framework for assisting flight controllers, which combines argumentation theory and model checking in the evaluation of trade-offs and compromises to be made in the presence of incomplete and potentially inconsistent information. We view a Hybrid Kripke model as a description of an ATC domain and we apply a rational decision strategy based on Hybrid Logics and Defeasible Reasoning to assist the process of model update when the system has to accommodate new properties or norm constraints. When the model fails to verify a property, a defeasible logic program is used to analyze the current state and perform updating operations on the model. The introduced decision making framework is tested on a recommender system in ATC and model update is demonstrated with respect to the verification and adaption of unmanned aerial vehicles routes in the air traffic space. The results show an important potential for the presented framework to be integrated directly into existing decision-making routines for achieving higher accuracy in recommender system methods.

Fault Tolerance Techniques in Heterogeneous Mobile Distributed Computing System- A Review

In Distributed computing system, Fault tolerance is an important issue because if the system fails then whole execution of a tasks stop. Fault tolerance is that asset of a system which provides the service to perform well still in case of any faults. A task applied on the real time distributed system must be feasible and reliable. The real time distributed systems for instance grid networks, robotics, air traffic control systems, etc. exceedingly depends on time. A single error in real time distributed system can cause a whole system failure, if not detected accurately and recovered at the proper time. Fault-tolerance is the key method which is often used to provide continue reliability in these systems. By applying extra hardware like processors, resource, communication links hardware fault tolerance can be achieved. A fault perhaps will occur for numerous reasons in distributed computing system such as failure of network, hardware or software failure etc. This paper defines various terminologies like failure, fault, faulty environment, fault tolerance, candidate node, redundancy etc. and explains fundamental concepts linked to fault tolerance in distributed systems. There are a lot of issues in distributed Computing system such as Emergent resource sharing, transparency, dependability, Complex mappings, concurrency, Fault tolerance etc. In this paper we focussed on the different fault tolerant approaches and fault tolerant terminologies used in distributed computing environment.

Air traffic optimization models for aircraft delay and travel time minimization in terminal control areas

This paper addresses the real-time aircraft routing and scheduling problem at a busy terminal control area (TCA) in case of traffic congestion. The problem of effectively managing TCA operations is particularly challenging, since there is a continuous growth of traffic demand and the TCAs are becoming the bottleneck of the entire air traffic control system. The resulting increase in airport congestion, economic and environmental penalties can be measured in terms of several performance indicators, including take-off and landing aircraft delays and energy consumption. This work addresses this problem via the development of mixed-integer linear programming formulations that incorporate the safety rules with high modeling precision and objective functions of practical interest based on the minimization of the total travel time and the largest delay due to potential aircraft conflicts. Computational experiments are performed on real-world data from Roma Fiumicino, the largest airport in Italy in terms of passenger demand. Traffic disturbances are generated by simulating sets of random landing/take-off aircraft delays. Near-optimal solutions of practical-size instances are computed in a short time via a commercial solver. The computational analysis enables the selection of those solutions offering the best compromise among the different objectives.