Browsing by Author "Saez Nieto, Francisco Javier"

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    Development of a new method for ATFCM based on trajectory-based operations
    (SAGE, 2017-09-03) Gatsinzi, Dany; Saez Nieto, Francisco Javier; Madani, Irfan
    This paper discusses a possibility to evolve the current Air Traffic Flow and Capacity Management towards a more proactive approach. This new method focuses on reducing the expected probability of air traffic control intervention based on “hot spot” identification and mitigation at strategic level by applying subliminal changes on the times of arrival at the crossing or merging points (junctions). The concept is fully aligned with the trajectory-based operation principles. The approach assumes that the changes on the times of arrival only demand small speed changes from the involved aircraft. In this study, the hot spots are defined as clusters of aircraft expected to arrive to the junctions. Two aircraft are said to be in the same cluster if their proximity and closure rate are below a given threshold. Some exercises are proposed and solved by applying this method. The obtained results show its ability to remove the potential conflicts by applying simple linear programming. This approach seeks to change the current capacity limiting factor, established by the number of aircraft occupying simultaneously each sector, to another parameter where the level of traffic complexity, flowing towards junctions, is identified and mitigated at strategic level. The speed changes, used as the control variable and computed before or during the flight, are designed to provide an adjustment on aircraft’s required time of arrival at the junctions in order to have a de-randomised and well-behaved (conflict free) traffic. This will enable improvements in airspace capacity/ safety binomial. It is recognised that this measure alone is unable to produce a conflict free airspace, and then other collaborative and coordinated actions, such as adjusting and swapping departing times at the departing airports (before the aircraft are taking off), offsetting some flights from nominal route, and allowing multi-agent separation management (while they are in flight) should be applied together with this method.
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    Discussion on density-based clustering methods applied for automated identification of airspace flows
    (IEEE, 2018-12-10) Verdonk Gallego, Christian Eduardo; Gómez Comendador, Victor Fernando; Saez Nieto, Francisco Javier; Garcia Martinez, Miguel
    Air Traffic Management systems generate a huge amount of track data daily. Flight trajectories can be clustered to extract main air traffic flows by means of unsupervised machine learning techniques. A well-known methodology for unsupervised extraction of air traffic flows conducts a two-step process. The first step reduces the dimensionality of the track data, whereas the second step clusters the data based on a density-based algorithm, DBSCAN. This paper explores advancements in density-based clustering such as OPTICS or HDBSCAN*. This assessment is based on quantitative and qualitative evaluations of the clustering solutions offered by these algorithms. In addition, the paper proposes a hierarchical clustering algorithm for handling noise in this methodology. This algorithm is based on a recursive application of DBSCAN* (RDBSCAN*). The paper demonstrates the sensitivity of these algorithms to different hyper-parameters, recommending a specific setting for the main one, which is common for all methods. RDBSCAN* outperforms the other algorithms in terms of the density-based internal validity metric. Finally, the outcome of the clustering shows that the algorithm extracts main clusters of the dataset effectively, connecting outliers to these main clusters.
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    ECAC use case of optimised pre-tactical time of arrival adjustments to reduce probability of separation infringements
    (Elsevier, 2018-07-19) Gatsinzi, Dany; Saez Nieto, Francisco Javier; Madani, Irfan
    Currently, a maximum allowable number of aircraft (A/C) entering and or within a sector for a given period is fixed. Anytime this threshold is reached, involved A/C are regulated by Air Traffic Flow and Capacity Management (ATFCM) to maintain an acceptable Air Traffic Controllers’ (ATCOs’) workload. This threshold is determined regardless of particular expected air traffic complexity, which may result from potential conflicts inherently in A/C’s flight plans that may greatly affect the ATCOs’ workload. This paper proposes a new ATFCM Demand and Capacity Balancing (DCB) methodology, applied to mitigate potential conflicts between A/C’s trajectories at pre-flight level, in order to reduce the current ATCO’s workload attributed to Separation Management (SM) interventions. This purpose is achieved through minor adjustments on A/C’s Times of Arrival (TOAs) at conflicted en-route junctions. The adjustments of A/C’s TOAs are implemented through minor changes on A/C’s speed profile, applied before and after each conflicted junction, while maintaining each A/C’s departure and Targeted Time of Arrival(TTA) at destination. The paper postulates that these TOA adjustments could be easily transformed into pre-tactical ATFCM DCB measures, assuming that ATFCM will issue Reference Business Trajectories (RBTs) containing time constraints at junctions, introduced to reduce the probability of conflicts. A case study of European Civil Aviation Conference (ECAC) air traffic network using real flight plan data is presented to show the validity of the methodology.
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    Hot spot identification and mitigation at strategic level by subliminal changes in aircraft time of arrival at junction
    (Eurocontrol, 2016-11-30) Gatsinzi, Dany; Saez Nieto, Francisco Javier; Madani, Irfan
    This paper presents some results obtained when applying a different criterion in Air Traffic Flow and Capacity Management (ATFCM) measures. The approach is based on reducing the probability of controller’s reactive interventions by "hot spot" identification and mitigation at strategic level, by applying subliminal changes on the aircraft’s Times of Arrival (TOA) at the crossing or merging points (junctions). The concept of this strategy is fully aligned with the Trajectory Based Operation (TBO) principles. It is assumed that the changes on the times of arrival only demand very small speed changes to the involved aircraft (A/C). In this assessment, hot spots are established by identifying groups of closely spaced A/C arriving at a junction. A hot spot isolates the set of A/C involved in multiple conflicts, close in their times of arrival at the junction, violating the minimum required “safe” time separation at the junction. The minimum safe time separation is established based on a chosen threshold for the probability of collision obtained by considering the different sources of uncertainties in the aircraft’s time of arrival at junction. Some exercises are proposed and solved by applying this method. The obtained results show its ability to remove the conflicts by applying simple linear optimization programming tool. The effect of this method on the aircraft’s operating costs is also analyzed. This approach also seeks to change the current capacity-limiting factor, established by the number of aircraft occupying simultaneously each sector, to another parameter where the level of traffic complexity, flowing towards junctions, will be identified and mitigated at strategic level.
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    Identification of spatiotemporal interdependencies and complexity evolution in a multiple aircraft environment
    (SESAR, 2017-11-30) Radanovic, Marko; Eroles, Miquel Angel Piera; Koca, Thimjo; Verdonk Gallego, Christian Eduardo; Saez Nieto, Francisco Javier
    To support future automated transitions among the ATM safety nets, this study elaborates identification of the complex traffic scenarios based on the concept of aerial ecosystems. As an extension of the TCAS operational domain and evolving from the separation management towards collision avoidance layer, the concept has been developed as a stepwise algorithm for identification of cooperative aircraft involved in the safety event – detected conflict, and negotiating their resolution trajectories before the ecosystem deadlock event occurs, in which at least one aircraft stays out of a conflict-free resolution. As a response to this threshold, the paper examines generation of both acceptable and candidate resolution trajectories, with respect to the original aircraft trajectories. The candidate trajectories are generated from a set of tactical waypoints and a return waypoint to the original trajectory. Described methodology has been practically implemented to one ecosystem scenario, characterizing its evolution in terms of the intrinsic complexity. By introducing the heading maneuver changes and delay in the resolution process, the results have shown how the scenario complexity is increasing, especially affected by the states of two aircraft in the initial conflict. Furthermore, it has been demonstrated an evolution in the amount of the acceptable and candidate trajectory solutions, for which the minimum complexity value is satisfied. A goal of the study was to explore the lateral resolutions capacity at certain moments and its timely decrement.