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The expected growth of air traffic in the following decades demands the implementation of new operational concepts to avoid current limitations of the air traffic management system. This paper focuses on the strategic conflict management for four-dimensional trajectories (4DT) in free-route airspace. 4DT has been proposed as the future operational...
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Context 1
... at intersection -í µí±¡ = 47:00 Figure 4 shows the 2D representation of the city-pairs Sevilla-Barcelona and Vigo-Murcia. It can be observed at both trajectories that they are constituted by four waypoints at which the 4DT temporary restrictions must be fulfilled. ...
Citations
... In FRA, users freely plan a route between a defined origin and destination, with the possibility of routing via intermediate points, which is more flexible. With the shift toward TBO, aircraft need to meet strict time and space constraints in the form of four-dimensional trajectory (4DT) [5]. In this framework, more accurate trajectory information can be provided for ATM. ...
We address the issue of multi-aircraft cooperative strategic trajectory planning in free-route airspace (FRA) in this study, taking into consideration the impact of time-varying and altitude-varying wind forecast uncertainty. A bi-level planning model was established in response to the properties of the wind. The upper level focused on minimizing the flight time, while the lower level aimed to reduce potential conflicts. Meanwhile, a heuristic approach based on conflict severity (CS) within the framework of a cooperative co-evolution evolutionary algorithm (CCEA) was proposed to accelerate the convergence speed in view of the complexity of this optimization issue. In order to conduct the experiments, historical data of 1479 flights over western Chinese airspace were retrieved. The number of conflicts, total flight time, total flight time variance, and deviation were used as indicators to evaluate the safety, efficiency, and predictability of the trajectory. When compared to a trajectory in the structured airspace, the optimal solution was conflict-free and reduced the total flight time by about 17.7%, the variance by 11.7%, and the deviation by 37.5%. Additionally, the contrast with the two-stage model demonstrated that the proposed method was entirely meaningful. The outcome of this survey can provide an effective trajectory-planning method, which is crucial for the sustainable development of future air traffic management (ATM).
... It was discovered that some efforts were made in the past by other authors to analyze the problem of conflict detection under the presence of uncertainties (i.e., wind, etc.). Such uncertainty related analyses were mainly conducted in terms of conflict detection and resolution [4][5][6] as conflict intensity and probability [7][8][9][10][11][12][13][14][15][16][17][18] involving accuracy or optimal path planning [19,20], or trajectory uncertainty [21,22] and efficiency [23] of aircraft trajectory prediction and synthesis [24], fuel consumptions [25], time management prior to take off with the aim of aircraft conflict situations deconfliction [26][27][28][29], etc. ...
... Wind is one of the influencing and uncertain factors on ATM related problems, and eventually on aircraft flight trajectory evolution, mainly on the dynamic aircraft system conflict point, which could be generated by winds, or which could be influenced/modified/transformed by prevailing winds [28]. So as the wind is the most important source of uncertainty in the trajectory configuration on a horizontal plane as due to the inaccuracy of the forecasts, such assumptions must be addressed: (1) wind uniformity throughout the trajectories during a simulation, and (2) the variety of wind regarding different geographical locations [28]. ...
... Wind is one of the influencing and uncertain factors on ATM related problems, and eventually on aircraft flight trajectory evolution, mainly on the dynamic aircraft system conflict point, which could be generated by winds, or which could be influenced/modified/transformed by prevailing winds [28]. So as the wind is the most important source of uncertainty in the trajectory configuration on a horizontal plane as due to the inaccuracy of the forecasts, such assumptions must be addressed: (1) wind uniformity throughout the trajectories during a simulation, and (2) the variety of wind regarding different geographical locations [28]. ...
A dynamic aircraft system conflict (concurrent event) situation exists when a time with a loss (-es) of separation (LOS) in their true or predicted trajectories is determined. Regional air traffic management (ATM) programs aim to make ATM safer and more efficient through a higher level of automation for such processes as dynamic aircraft systems concurrent events detection and, consequently, resolution. Therefore, wind and aircraft speed uncertainty parameters should be properly addressed. This paper offers an approach to a dynamic aircraft system flying under a certain concurrent event situation and demonstrates situation stochastic distribution results (output) based on determined wind speed values (while wind direction angles and the dynamic aircraft system speed values are random). Based on these facts, the stochastic dynamic aircraft system conflict distribution information under determined and random parameters might be retrieved at any specific (preferred) time moment. The observations of this study disclosed that such stochastic output data might have a certain impact on safety matters (potential “domino effect” conflicts on a horizontal plane) and on the efficiency (i.e., flight distance which eventually is a determinant of flight time, fuel costs, delays, emissions, monitoring, etc.).
... The fundamental problem addressed in this paper of ensuring extremely low collision probabilities has implications for conflict resolution measures [55,56], which apply both to manned and unmanned aircraft if operating in non-segregated airspace [57][58][59], as an alternative to geofencing [60]. Conflict resolution may be automated [61] if reliable trajectory information is available [62], which is not always the case, for example for aircraft collision with birds [63]. ...
... All the steps from the choice of the probability distribution for large flight path deviations up to the final metrics for collision risk have been documented in some detail, because they apply to any encounter geometry, not only flight along air corridors, but also to level crossings [55] and climbing and descending flights [53]. A complete flight plan can often be described by straight paths between waypoints and curved trajectories approximated by straight segments. ...
The separation of aircraft in cruising flight in air corridors is based on the assurance of an extremely low probability of collision due to position inaccuracy caused by navigation errors, atmospheric disturbances, or other factors. The appropriate standard is the International Civil Aviation Organization (ICAO) Target Level of Safety (TLS) of frequency of collision less than 5 × 10−9 per flight hour. An upper bound for the collision probability per unit distance is the probability of coincidence, in the case of aircraft flying at the same speed along parallel tracks in the same direction. This leads to the case of two aircraft flying at a constant separation, for which at least three probabilities of coincidence can be calculated: (i) the maximum probability of coincidence at the most likely point; (ii) the cumulative probability of coincidence integrated along the flight path; and (iii) the cumulative probability of coincidence integrated over all space. These three probabilities of coincidence are applied to the old standard and new reduced vertical separations of 2000 ft and 1000 ft respectively, for comparison with the ICAO TLS, and also to assess their suitability as safety metrics. The possibility is raised of complementing the ICAO TLS 5 × 10−9 per hour, which is suitable for the cumulative probability of collision, by two additional safety metrics: (i) one per hour flown squared, which is suitable for comparison with the maximum joint probability density of collision; and (ii) another times hour flown, for comparison with the three-dimensional cumulative probability of coincidence. These three metrics (i) to (iii) have distinct dimensions, give different information, and could be alternatives or supplements.
Purpose
The purpose of this paper is to create a flight route optimization for all flights that aims to minimize the total cost consists of fuel cost, ground delay cost and air delay cost over the fixed route and free route airspaces.
Design/methodology/approach
Efficient usage of current available airspace capacity becomes more and more important with the increasing flight demands. The efficient capacity usage of an airspace is generally in contradiction to optimum flight efficiency of a single flight. It can only be achieved with the holistic approach that focusing all flights over mixed airspaces and their routes instead of single flight route optimization for a single airspace. In the scope of this paper, optimization methods were developed to find the best route planning for all flights considering the benefits of all flights not only a single flight. This paper is searching for an optimization to reduce the total cost for all flights in mixed airspaces. With the developed optimization models, the determination of conflict-free optimum routes and delay amounts was achieved with airway capacity and separation minimum constraints in mixed airspaces. The mathematical model and the simulated annealing method were developed for these purposes.
Findings
The total cost values for flights were minimized by both developed mathematical model and simulated annealing algorithm. With the mathematical model, a reduction in total route length of 4.13% and a reduction in fuel consumption of 3.95% was achieved in a mixed airspace. The optimization algorithm with simulated annealing has also 3.11% flight distance saving and 3.03% fuel consumption enhancement.
Research limitations/implications
Although the wind condition can change the fuel consumption and flight durations, the paper does not include the wind condition effects. If the wind condition effect is considered, the shortest route may not always cause the least fuel consumption especially under the head wind condition.
Practical implications
The results of this paper show that a flight route optimization as a holistic approach considering the all flight demand information enhances the fuel consumption and flight duration. Because of this reason, the developed optimization model can be effectively used to minimize the fuel consumption and reduce the exhaust emissions of aircraft.
Originality/value
This paper develops the mathematical model and simulated annealing algorithm for the optimization of flight route over the mixed airspaces that compose of fixed and free route airspaces. Each model offers the best available and conflict-free route plan and if necessary required delay amounts for each demanded flight under the airspace capacity, airspace route structure and used separation minimum for each airspace.
The integration of Remotely Piloted Aircraft System (RPAS) in non-segregated airspace is one of the most demanding challenges that the aviation community must face in the years ahead. This article develops the flight-plan processing from a risk-based methodology. The risk-based methodology is underpinned by an in-depth safety analysis throughout the three temporary horizons of the Air Traffic Flow and Capacity Management system: strategical, pre-tactical and tactical. The flight-plan processing demands different measures depending on the temporary horizon. The measures mean geographical restrictions (airways or air corridors segregated for RPAS) and temporary restrictions (periods in which RPAS cannot operate). Both restrictions ensure that RPAS operation is safe and do not generate interactions with conventional aircraft. The last goal of this approach is to provide the required information to the RPAS operator based on the information available from the Network Manager (NM). The communication and information flow between the RPAS operator and the NM are detailed to validate flight-plan processing. If the initial flight plan is not affordable, the NM provides modifications during the flight-plan re-processing. The methodology is applied in the Spanish upper airspace. The results confirmed the validity and leeway of the flight-plan processing, although its implementation demands further improvements based on air traffic flow and path uncertainty.
Purpose
The purpose of this paper is to create and analyze the effectiveness of a new runway system, which is totally created for the future free route operations.
Design/methodology/approach
This paper researches and analyses the new generated runway concept with the fast time simulation method. Fuel consumption and environmental effect of the new runway system are calculated based on simulation results.
Findings
According to different traffic density analyses the Omnidirectional Runway with Infinite Heading (ORIH) reduced fuel consumption and CO 2 emissions up to 46.97%. Also the total emissions of the ORIH concept, for the hydro carbon (HC), carbon monoxide (CO) and nitrogen oxides (NOx) pollutants were lower than the total emissions with the conventional runway up to 83.13, 74.36 and 51.49%, respectively.
Practical implications
Free route airspaces bring many advantages to air traffic management and airline operations. Direct routes become available from airport to airport thanks to free route airspace concept. However, conventional single runway structure does not allow aircraft operations for every direction. The landing and take-off operations of a conventional airport with a single runway must be executed with only two heading direction. This limitation brings a bottleneck direct approach and departure route usage as convenient with free route airspace concept. This paper suggests and analyzes the omnidirectional runway with infinite heading (ORIH) as a solution for free route airspace.
Originality/value
This paper suggests a new and futuristic runway design and operation for the free route operations. This paper has its originality from the suggested and newly created runway system.
This article evaluates Machine Learning (ML) classification techniques applied to air-traffic conflict detection. The methodology develops a static approach in which the conflict prediction is performed when an aircraft pierces into the airspace. Conflict detection does not evaluate separation infringements but a Situation of Interest (SI). An aircraft pair constitutes a SI when it is expected to get with a horizontal separation between both aircraft closer than 10 Nautical Miles (NM) and a vertical separation closer than 1000 feet (ft). Therefore, the ML predictor classifies aircraft pairs between SI or No SI pairs. Air traffic information is extracted from The OpenSky Network that provides ADS-B trajectories. ADS-B trajectories do not offer enough SI samples to be evaluated. Hence, the authors performed simulations varying the entry time of the trajectories to the airspace within the same time period. The methodology was applied to a portion of Switzerland airspace, and simulations reached a 5% rate of SI samples. Cost-sensitive techniques were used to handle the strong imbalance of the database. Two experiments were performed: the Pure model considered the whole database, and the Hybrid model considered aircraft pairs that intersect horizontally closer than 20 NM and vertically lower than 1000 ft. The Hybrid model provided the best results achieving 72% recall, representing the success rate of Missed alerts and 82% accuracy, which means the whole predictions’ success rate.
Given the ongoing interest in the application of Machine Learning (ML) techniques, the development of new Air Traffic Control (ATC) tools is paramount for the improvement of the management of the air transport system. This article develops an ATC tool based on ML techniques for conflict detection. The methodology develops a data-driven approach that predicts separation infringements between aircraft within airspace. The methodology exploits two different ML algorithms: classification and regression. Classification algorithms denote aircraft pairs as a Situation of Interest (SI), i.e., when two aircraft are predicted to cross with a separation lower than 10 Nautical Miles (NM) and 1000 feet. Regression algorithms predict the minimum separation expected between an aircraft pair. This data-driven approach extracts ADS-B trajectories from the OpenSky Network. In addition, the historical ADS-B trajectories work as 4D trajectory predictions to be used as inputs for the database. Conflict and SI are simulated by performing temporary modifications to ensure that the aircraft pierces into the airspace in the same time period. The methodology is applied to Switzerland’s airspace. The results show that the ML algorithms could perform conflict prediction with high-accuracy metrics: 99% for SI classification and 1.5 NM for RMSE.
