Airspace Users Research Articles

An optimization model to fit airspace demand considering a spatio-temporal analysis of airspace capacity

The European and U.S. airspace systems are highly congested at certain peak time intervals. Controllers’ workloads have reached generally accepted limits; therefore, many highly demanded sectors are subject to traffic regulations and restrictions during many hours of each day. A lack of a spatio-temporal analysis of the airside capacity management tools generates airside delays at the destination airport in the form of holding or path-stretching in terminal manoeuvring areas, or even during the cruise by re-routing. These emergent dynamics are demonstrated every day by the urgent need for new and better tools for analyzing and making strategic and tactical decisions that neither induce delays nor negatively impact daily operations. This paper presents an optimization model for airspace capacity–demand management that performs an efficient departure time bounded adjustment configuration for trajectory based operations. This optimization model is supported by the 4D trajectories paradigm, in which a discrete event model has been developed to formalize the trajectories’ spatio-temporal interdependencies. Based on the elements and parameters declared on the validated coloured Petri net model, a set of constraints is obtained. By means of constraint programming, feasible solutions for demand–capacity imbalances are proposed for a case study scenario, while the original departure slots are preserved in addition to the airspace users’ preferences. The results obtained show the advantages in terms of capacity and robustness that can be achieved by applying an efficient departure time bounded adjustment configuration.

ROBUST AERIAL OBJECT TRACKING IN HIGH DYNAMIC FLIGHT MANEUVERS

Abstract. Integrating drones into the civil airspace is one of the biggest challenges for civil aviation, responsible authorities and involved com- panies around the world in the upcoming years. For a full integration into non-segregated airspace such a system has to provide the capability to automatically detect and avoid other airspace users. Electro-optical cameras have proven to be an adequate sensor to detect all types of aerial objects, especially for smaller ones such as gliders or paragliders. Robust detection and tracking of approaching traffic on a potential collision course is the key component for a successful avoidance maneuver. In this paper we focus on the aerial object tracking during dynamic flight maneuvers of the own-ship where accurate attitude information corresponding to the camera images is essential. Because the ’detect and avoid’ functionality typically extends existing autopilot systems the received attitude measurements have unknown delays and dynamics. We present an efficient method to calculate the angular rates from a multi camera rig which we fuse with the delayed attitude measurements. This allows for estimating accurate absolute attitude angles for every camera frame. The proposed method is further integrated into an aerial object tracking framework. A detailed evaluation of the pipeline on real collision encounter scenarios shows that the multi camera rig based attitude estimation enables the correct tracking of approaching traffic during dynamic flight, at which the tracking framework previously failed.

The Single European Sky: What about the Liability Aspect?

Following the liberation of European air transport in the 1990s, the Union has tried to implement dramatic changes by enacting the Single European Sky (SES) Regulations. The cornerstone idea of the SES Regulations is to create so-called Functional Airspace Blocks or FABs. These FABs will normally satisfy the growing capacity requirements of all airspace users and minimize delays by managing air traffic more dynamically. This will have as immediate consequences an increase in efficiency. This article will examine each of the Treaties establishing the FABs in detail with regard to the liability aspect only and, while acknowledging their advantages, it will point out the differences in the protection they offer and the consequences the author sees happening. This article will also suggest several improvements. The primary focus of the article is the liability aspect in the FAB Treaties, but references to agreements between air navigation service providers (ANSPs) will also be included. Through showing the advantages of the proposal, this article highlights the hypothesis that the SES will not bring any changes to the current liability framework; to the contrary, it will further blur the general picture by adding a layer of fragmentation.

Detect and Avoid for Small Unmanned Aircraft Systems Using ADS-B

With the increasing demand to integrate unmanned aircraft systems (UAS) into the National Airspace System (NAS), new procedures and technologies are necessary to ensure safe airspace operations and minimize the impact of UAS on current airspace users. Currently, small UAS face limitations on their use in civil airspace because they lack the ability to detect and avoid other aircraft. This article presents a framework that consists of an Automatic Dependent Surveillance-Broadcast (ADS-B)-based sensor, track estimator, conflict/collision detection, and resolution that mitigates collision risk. ADS-B offers long-range, omni-directional intruder detection with comparatively few size, weight, power, and cost demands. The proposed conflict/collision detection and planning algorithms for conflict/collision resolution are designed in the local level frame, which is the unrolled, unpitched body frame where the ownship is stationary at the center of the map. The path planning method is designed to be multi-resolutional at increasing distance from the ownship to account for both self-separation and collision avoidance thresholds. We demonstrate and validate this approach using simulated ADS-B measurements.

English

Each year the demand of aviation services is increasing but the European airspace is still fragmented according to national borders. Delays of implementing Single European Sky are increasingly high. Consequently, each year the aviation industry loses a lot of money, among others, because of flight route extensions or higher fuel consumption. A comparison between Air Traffic Management-Related Operational Performance U.S./Europe shows how inefficient ATM is in Europe and how costly for the airspace users. This study also describes the benefits and costs of the SES full implementation.

A Framework for Assessing and Managing the Impact of ANSP Actions on Flight Efficiency

This paper presents a framework to assess Air Traffic Management (ATM) performance in relation to flight efficiency. The main philosophy behind the approach presented in this paper is to quantify the quality of the service delivered by an Air Navigation Service Provider (ANSP) to an airline in terms of meeting commonly agreed-upon objectives. The definition is, therefore, aligned with the future paradigm of Trajectory Based Operations, where achieving the trajectory agreed between the ANSP and the airspace user becomes the focus. A staged approach to flight efficiency assessment is proposed to quantify the quality of the ANSP’s service in terms of both “facilitating what has been agreed” and “improving what can be agreed.” The framework promotes the development of more consistent efficiency performance metrics between ANSPs, by defining clear definitions for assessment references. Application of the framework is illustrated with several examples using the Airservices Dalí trajectory modeler.

Generating Certification Evidence for Autonomous Unmanned Aircraft Using Model Checking and Simulation

The use of unmanned aircraft for civil applications is expected to increase over the next decade, particularly in so-called dull, dirty, and dangerous missions. Unmanned aircraft will undoubtedly require some form of autonomy to ensure safe operations for all airspace users. However, to be used for civil applications, unmanned aircraft must gain regulatory approval in a process known as “certification”. This paper presents a proof-of-concept approach to the generation of certification evidence for autonomous unmanned aircraft based on a combination of formal verification and flight simulation. In particular, a class of autonomous systems controlled by rational agents is examined, and we give examples of 23 different properties, based on the rules of the air and notions of airmanship, which can be used in the formal model checking of rational agents controlling autonomous unmanned aircraft. Our techniques can be based on either 1) implicit models of the aircraft’s physical environment specified in terms of the range of sensor inputs the autonomous system may receive, or 2) more explicit physical models of the environment. Finally, we provide a description of how such formal verification can be used to refine the implementation of autonomous systems for unmanned aircraft.

국가공역체계 내에서 군용 무인항공기 비행규칙에 관한 제언

Military UAV(Unmanned Aerial Vehicle) operated as a RC(Remotely Control) model level within the limit of the military special use airspace until now. However, the high and medium altitude of URA(Unmanned Reconnaissance Aircraft) which the ROKAF have been trying to import recently is at the UAV level and needs the criteria for the classified airspace flights. The required flight criteria includes operator location, mission operation limit, equipment, etc., which are the principle and standard applied based on the airspace use for UAV. Also, the general flight rules, visual flight rules, instrument flight rules are required in order to have to be applied to the actual flight. Besides, an appliance regulation needs to be arranged regarding two-way communication, ATC and communication issue, airspace and area in-flight between UAS( Unmanned Aircraft System) users. An operation of the UAV in the air significantly requires the guarantee of the aircraft's capacity, and also the standardized flight criteria. A safe and smooth use is ensured only if this criteria is applied and understood by the entire airspace users. For the purpose, a standardized military UAV flight operations criteria that is to be applied for each airspace by UAV is to be prepared through analysis of the present state, a legend UAV system, and a special character analysis.

Anticipatory modulation of air navigation charges to balance the use of airspace network capacities

Excess of air traffic demand over available capacity in certain segments of the European airspace network typically results in substantial delays imposed on airspace users, despite a possible parallel existence of underutilised adjacent network segments. Recent EU legislation lays down a performance scheme for air navigation services (ANS) and network functions, in an attempt to improve overall efficiency of the ANS, across the areas of safety, environment, capacity and cost-efficiency. It sets a framework for a possible introduction of incentive schemes which would drive the behaviour of involved stakeholders towards meeting the established performance objectives. In such a context, this paper examines an economic concept to incentivise a more efficient use of available network capacities. We put forward a method and develop a model for an anticipatory, time-dependent modulation of ANS charges, aiming to alleviate the demand-capacity imbalance on an airspace network, at minimal cost to airspace users. The proposed method is conceptualised as a bi-level optimisation problem, reconciling the perspectives of network manager and individual network users. The results of a medium-scale real-life case study indicate that an imposition of a revenue-neutral matrix of tolls and rebates on a congested airspace network may yield a fairly equitable route assignment, which seems capacity-wise more efficient than current administrative demand management practices.

Strategic de-confliction in the presence of a large number of 4D trajectories using a causal modeling approach

This paper presents a strategic de-confliction algorithm based on causal modeling developed under the STREAM project and launched under the umbrella of the Single European Sky ATM Research (SESAR) Program. The basic underlying concept makes use of the enriched information included in the Shared Business Trajectories (SBTs) of the flights prior to takeoff (or in the Reference Business Trajectories (RBTs) if the flight is airborne) to allocate conflict-free trajectories in a traffic planning phase that should lead to an actual conflict-free scenario in the flight execution phase in the absence of flight and/or network uncertainties. The proposed approach could decrease the workload of the air traffic controllers, thus improving the Air Traffic Management (ATM) capacity while meeting the maximum possible expectations of the Airspace Users’ requirements in terms of horizontal flight efficiency. The main modules of the implemented system are also presented in this paper; these modules are designed to enable the processing of thousands of trajectories within a few seconds or minutes and encompass a global network scope with a planning horizon of approximately 2–3h. The causal model applied for network conflict resolution and flight routing allocation is analyzed to demonstrate how the emergent dynamics (i.e., domino effects) of local trajectory amendments can be efficiently explored to identify conflict-free Pareto-efficient network scenarios. Various performance indicators can be taken into account in the multi-criteria optimization process, thus offering to the network manager a flexible tool for fostering a collaborative planning process.

Benchmarking of Air Navigation Services Providers by the Use of Composite Flight Hours; True or False?

European Air Traffic Management appears to be, in comparison to other similar systems in the world, cost inefficient and therefore constantly under pressure of airspace users to optimize. Benchmarking results are valuable for managerial decision making processes, however it is safe to assume that the methodology used, favours a narrow segment of ANSPs. By improvements introduced through this study, in particular in computing the Composite Flight Hours, the managerial decision-making process could most probably be more adequately supported.

Development of a Probabilistic Convective Weather Forecast Threshold Parameter for Flight-Routing Decisions

Abstract This paper presents a method for determining a threshold value of probabilistic convective weather forecast data. By synchronizing air traffic data and an experimental probabilistic convective weather forecast product, it was observed that aircraft avoid areas of specific forecasted probability. Both intensity and echo top of the forecasted weather were synchronized with air traffic data to derive the probability threshold parameter. This value can be used by dispatchers for flight planning and by air traffic managers to reroute streams of aircraft around convective cells. The main contribution of this paper is to provide a method to compute the probability threshold parameters using a specific experimental probabilistic convective forecast product providing hourly guidance up to 6 h. Air traffic and weather data for a 4-month period during the summer of 2007 were used to compute the parameters for the continental United States. The results are shown for different altitudes, times of day, aircraft types, and airspace users. Threshold values for each of the 20 Air Route Traffic Control Centers were also computed. Additional details are presented for seven high-altitude sectors in the Fort Worth, Texas, center. For the analysis reported here, flight intent was not considered and no assessment of flight deviation was conducted since only aircraft tracks were used.

FORMATION OF METHODOLOGY TO MODEL REGIONAL AIRSPACE WITH REFERENCE TO TRAFFIC FLOWS

As the number of flights increases, the ATM system, which forms the basis for air navigation services, has to ensure that those flights are not only safe but also effective. Considering the growing impact of traffic flows and taking into account the not-always-satisfactory indicators of the efficiency of the ATM system, the current ATM system needs changes. Airspace is currently fragmented along national borders, which limits opportunities or even completely prevents the possibility to improve the efficiency of flights, i.e. to perform flights of optimal trajectories and to avoid delays. One of the conditions allowing the current ATM system to become more effective is the amalgamation of the airspace parts or blocks within which (currently in the airspace along national boarders) air navigation services are organised. Comparisons between the ATM systems functioning in different regions of the world show that the less fragmentation there is, the more efficient flights are. One of the main tasks remains, i.e. to establish airspace blocks that meet the expectations of the airspace users.

ANALYSIS OF AIRSPACE ORGANIZATION CONSIDERING AIR TRAFFIC FLOWS

Aviation is one of the most rapidly developing types of transport playing a crucial role in the modern world. Aviation has a sensitive response to any economic or social changes and painful aviation catastrophes. In spite of increasing the flows of passengers and flights, for certain reasons, the aviation system does not always satisfy the expectations of the airspace users in the sense of efficiency. The effectiveness of air transport operations is determined by both a reduction in the costs of every airspace user and the efficiency of the air traffic management system. Airspace organization performed by the air traffic management system, i.e. its adaptation to the performance of appropriate air navigation services, largely defines the efficiency of these services. Due to various reasons, presently, the area of airspace and airspace management has remained one of the largest and incompletely used aviation resources. Beside other appropriate means, the organization of air traffic management and airspace establishes flight conditions and determines the efficiency of flight trajectories and regularity. A comparison of air traffic management systems of different regions identifies the obstacles that do not allow ensuring the maximum results of flight efficiency in any place. One of the main reasons is the high fragmentation of the specified regions that mostly coincide with the state borders. The above reasons show that in order to efficiently develop aviation, the successful development of that to the extent of one country is not enough. Thus, the best results will only be reached solving the existing problems and intended challenges to the extent of a few countries – up to the extent of the whole region. The aim of research is to define a methodology allowing the organization of regional airspace according to the flows of air traffic and subsequently enabling to solve flight efficiency problems related to air traffic management. For space evaluation, the paper suggests using rectangular grids the application of which makes possible dividing the researched space more easily and exactly. Considering the examples of air traffic management systems demonstrating the best results of efficiency, it can be exactly assumed about the number of possible airspace blocks complying with the flows of flights in the analyzed airspace. In case, a preliminary number of the wanted clusters is known, it is purposeful to apply the method of the cluster analysis of K-means with necessary limitations to the formed building airspace blocks and to determine the optimum version taking into account the analyzed ones. The paper suggests representing points having appropriate weighted coefficients during the stage of clustering rather than using grid cells. The optimization of the obtained airspace blocks is necessary in case the formed blocks do not properly comply with the aims raised. The application of the methodology suggested in the paper enables dividing the airspace of a big territory into airspace blocks according to the flows of flights independent from the air way network, flight intensity and the collocation of the airspace elements of a special purpose.

Contributions of advanced taxi time calculation to airport operations efficiency

The current paper stresses the high priority of accurate taxi time calculation and suitable pre-departure management strategies in the context of Airport Collaborative Decision Making (Airport CDM) and contributes to an improved overall understanding of the associated requirements. Based on data analysis performed at Frankfurt Airport this paper compares results of static and advanced taxi time calculation. Contrarily to static calculations, where look-up tables for stand-runway-relations are used, advanced taxi time calculation takes into account the current traffic situation and calculates taxi times dynamically. The paper shows that the taxi time uncertainties when using static data lead to only 42% of flights within the accuracy of ± 2 minutes according to the requirements of the Airport CDM Implementation Manual for short term predictions (maximum 30 minutes before off-block). The application of advanced taxi time calculation leads to significant improvements with 66% of flights within the accuracy of ± 2 minutes at the moment when the aircraft leaves the stand. Hence, app. 50% more predictions are compliant with the Airport CDM requirements compared to static data. Based on these results, the paper assesses the effects of improved taxi time predictability onto airport operation efficiency with particular focus set to taxi time reductions due to minimized queuing at the departure runway. It is shown that advanced taxi time calculation contributes to a reduction of delays, fuel burn, CO2 emissions and costs for airspace users compared to the use of static look-up tables. However, it is also emphasized that the shifting of delays from the runway holding positions to the stand does not necessarily contribute to efficiency improvements. It is recommended that the pre-departure sequencing strategy must be chosen cautiously in dependence on the fuel and time costs for airlines as well the amount of departure delay that has to be absorbed.

The Smart Skies project

The Smart Skies project is an ambitious and world-leading research endeavor exploring the development of key enabling technologies, which support the efficient utilization of airspace by manned and unmanned airspace users. This provides a programmatic description of the research and development of: an automated separation management system; a mobile aircraft tracking system; and aircraft-based sense-and-ad technologies. A summary of the results from a series of real-world flight testing campaigns is also presented.

Evaluation of a Transfer of Control Concept for Airborne Self-Separation

Airborne self-separation is one of the concepts which is currently under discussion as a key feature in NextGen/SESAR's future air-transport system. Self-separation of aircraft is expected to provide higher capacity and safety levels as well as a better consideration of the different needs of airspace users. However, in order to become operational self-separation requires certain airspace structures and procedures. Compared to earlier studies by FAA and NASA which are based on the concept of shared control by ATC and flight crews, our approach uses a transfer of control concept where the control authority for aircraft separation tasks is shifted from ATC to flight crews and back to ATC. In order to better understand possible roles and role changes of future aviators, we conducted an integrated simulation study with 15 airline pilots and five air-traffic controllers on a low-cost simulation platform called AviaSim. In an experimental design with repeated measurements, the subjects flew three scenarios with and without control shift for self-separation. The findings show that operators' workload and situation awareness scores are better balanced under the shift-of-control condition compared to the traditional ground-control condition. Additionally, effects of transfer of control on preferred separation tactics and safety indicators are examined.

A Centralized Multi-Agent Negotiation Approach to Collaborative Air Traffic Resource Management Planning

Demand and capacity imbalances in the US national airspace are resolved using traffic management initiatives designed, in current operations, with little collaboration with the airspace users. NASA and its partners have developed a new collaborative concept of operations that requires the users and airspace service provider to work together to choose initiatives that better satisfy the business needs of the users while also ensuring safety to the same standard as today. In this paper, we describe an approach to implementing this concept through a software negotiation framework underpinned by technology developed in the artificial intelligence community. We describe our exploration of peer-to-peer negotiation and how the number of conversation threads and the time sensitivity of offer acceptance led us to a centralized approach. The centralized approach uses hill climbing to evaluate airport slot allocations from a user perspective and a linear programming solver to seek solutions compatible across the user community. Our experiments with full sized problems identify the potential operational benefits as well as limitations, and where future research needs to be focused.

Sequential Traffic Flow Optimization with Tactical Flight Control Heuristics

‡A sequential optimization method is applied to manage air traffic flow under uncertainty in airspace capacity and demand. To support its testing, a decision support system is developed by integrating a deterministic integer programming model for assigning delays to aircraft under en route capacity constraints to reactively account for system uncertainties. To reduce computational complexity, the model assigns only departure controls, while a tactical control loop consisting of a shortest path routing algorithm and an airborne holding algorithm refines the strategic plan to keep flights from deviating into capacity constrained airspace. This integrated approach is used to conduct thirty-two, 6-hour fast-time simulation experiments to explore variations in the number and severity of departure controls, tactical reroutes, and airborne holding controls. Three feasible types of traffic flow controls emerged. The first type relied primarily on departure controls and strategic reroutes on the 300 to 400 nmi look-ahead horizon and worked best when rerouting occurred at a frequency of 10 to 15 minutes. The second type generated more tactical reroutes on the 200 ‐ 300 nmi look-ahead horizon and required little airborne holding or pre-departure control when rerouting occurred at a frequency of 5 minutes. The last type relied heavily on airborne holding controls and infrequent updates to the weather avoidance reroutes. This last type was the least desirable solution due to the impact of its airborne holding on airspace complexity and airspace users.

Metrics for Traffic Complexity Management in Self-Separation Operations

Distributed control concepts, where some air traffic management functions are performed by airspace users, have been proposed to help address the rising demand for air travel. For example, delegation of traffic separation responsibility to the flight crew can be enabled by new cockpit automation that supports the separation task for that aircraft. As more equipped aircraft provide their own separation service, it creates the potential to adapt airspace capacity to the increasing demand. However, this distribution of tasks and decision making raises the concern that independent user actions will increase the complexity of the traffic system, possibly leading to a disruption of scheduled operations as safety is maintained. To address this concern, the authors propose the introduction of decision-making metrics for preserving user trajectory flexibility. The hypothesis is that such metrics, when added to trajectory management automation, will make independent user actions naturally mitigate traffic complexity. In this paper, trajectory flexibility is formally and mathematically defined in terms of robustness and adaptability to disturbances. A metric estimation method is developed assuming discrete time and discrete maneuvering-degree-of-freedom changes, resulting in a map of flexibility over the trajectory solution space which can be used by a real-time trajectory planner. Initial insights into the relationship between trajectory planning using this metric map and traffic complexity are demonstrated through analyzing a simple scenario including required time of arrival and traffic constraints. The scenario demonstrates that preserving flexibility results in reducing relative heading between aircraft—one method for potentially reducing apparent traffic complexity.