Data-driven methodology for uncertainty quantification of aircraft trajectory predictions

This work present a framework based on datadriven techniques for quantifying and chaos theory for propagating the uncertainty present in the aircraft trajectory prediction process when computing the expected trajectory from a given flight plan. The developed framework employs data assimilation models to capture real-time information from the air traffic system and introduces a novel methodology in order to account for the uncertainty of the weather conditions. The comparison of the resulting set of probabilistic trajectories and the actually flown ones proves how the former could be a key enabler to support envisioned trajectory-based operation concepts and modern airline operations planning.Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i InfraestructuraObjectius de Desenvolupament Sostenible::12 - Producció i Consum ResponsablesPostprint (published version

Peripheral blood biomarkers in multiple sclerosis.

Multiple sclerosis is the most common autoimmune disorder affecting the central nervous system. The heteroge-neity of pathophysiological processes in MS contributes to the highly variable course of the disease and unpre-dictable response to therapies. The major focus of the research on MS is the identification of biomarkers inbiologicalfluids, such as cerebrospinalfluid or blood, to guide patient management reliably. Because of the diffi-culties in obtaining spinalfluid samples and the necessity for lumbar puncture to make a diagnosis has reduced,the research of blood-based biomarkers may provide increasingly important tools for clinical practice. However,currently there are no clearly established MS blood-based biomarkers. The availability of reliable biomarkerscould radically alter the management of MS at critical phases of the disease spectrum, allowing for interventionstrategies that may prevent evolution to long-term neurological disability. This article provides an overview ofthis researchfield and focuses on recent advances in blood-based biomarker researc

Flugführungssysteme für Transportflugzeuge

4D-Navigation, Trajektorienberechnung, kooperatives Planen, Trajektorienverhandlung, Moderne Anflugprozeduren, Ergebnisse aus Flugversuchen und Simulatione

FAGI - Future Air Ground Integration

Moderne Flugzeuge mit 4D-Flight Management System (FMS) sind in der Lage, Anflüge zu planen, die besonders treibstoffsparend und lärmarm sind. Das wird in der Regel durch einen Continuous Descent Approach erreicht, bei dem die Triebwerke im Idle sind (-> „Segelflugzeug“). Ein Reagieren auf Anweisungen von ATC ist jedoch schwer möglich, sobald das Flugzeug sich im Sinkflug befindet. Daher werden lärmarme Anflugverfahren derzeit nur zu verkehrsarmen Zeiten verwendet. Durch Kombination aus spätem Zusammenführen der lateralen Flugrouten und zeitbasierter Separation auf den Anflugrouten zeigt FAGI einen möglichen Weg zur treibstoff- und lärmeffizienten Führung von Luftfahrzeugen in einem erweiterten Anflugsektor, auch zu verkehrsstarken Zeiten. Flugzeuge, die mangels Bordausrüstung nicht 4D-genau fliegen können, werden über ein bodenbasiertes 4D-Führungsmodul integriert. Es wird eine Motivation für die Inhalte des DLR-internen Projektes FAGI gegeben und das ETMA-Konzept vorgestellt. Speziell wird auf die notwendige/hinreichende Genauigkeit und Verlässlichkeit einer Synchronisation der Bord- und Bodentrajektorie eingegangen

Enabling Green Profiles in High Density Traffic

Today, the usage of highly efficient flight procedures often lacks on the missing integration between air and ground based tools. Typically, modifications on both airborne and ground side are necessary to fully benefit from new technologies. Furthermore, modifications are usually expensive and therefore are only implemented if the counterpart also invests in the corresponding work. In the past ten years, the Institute of Flight Guidance in Braunschweig performed extensive investigations on how airborne capabilities can be improved. Studies with the A330 Full Flight Simulator of ZFB Berlin and DLR’s testing aircraft ATTAS both using DLR’s Advanced Flight Management System onboard proved a highly accurate predictability of 4D-trajectories. Based on aircraft model and actual weather forecast, the 4D-FMS enables fuel efficient and noise optimized continuous descent approaches. With a planning horizon of about 20 minutes, threshold times were anticipated with a deviation of only +/-5s and an altitude precision of +/-150ft during the whole approach. Having a look at today’s traffic mixture and its equipage level, about 11% of all aircraft flying in Europe are capable of reaching time constraints of +/-6s. At least in high traffic situations, current terminal manoeuvring area concepts do not support 4D-capable aircraft in flying fuel efficient and noise abating profiles. In contrast, equipped aircraft are all forced to early join the same lateral flight path flying at normalized speeds to ensure separation and avoid a break-in of capacity. Thus, fuel and noise efficient approaches are currently performed in low traffic scenarios only. In 2007, DLR launched the project “Future Air Ground Integration (FAGI)” that tries to solve today’s trade-off between capacity and environmental sustainability. The major concept element is usage of trajectory based TMA operations to combine aircraft optimized flight profiles with a high airport throughput. A time based late merging allows aircraft to fly their preferred trajectories by staggering them laterally in an extended terminal manoeuvring area with a time constraint to be fulfilled at a late merging point. Due to the high navigation accuracy 4D-capable aircraft are able to follow their predicted flight path on their own. Unequipped aircraft are supposed to be integrated by means of a ground based 4D-guidance module that is also described in this work. The proposed concept integrates 4D-equipped aircraft in the normal traffic flow without losing aircraft throughput. The generic concept is fully scalable based on the equipage degree and leaves high flexibility for short term departures, reaction on contract violations (e.g. equipped aircraft not meeting their constraints) and emergency situations. Several fast and real time simulations proved that the proposed concept is a possible way to go. Results from these simulations and from first trials with in-the-loop air traffic controllers are presented

Optimizing Tomorrows ATM Using 4D-Trajectory-Based Operations

Performing the paradigm shift to 4D-Trajectory-Based Operations will involve several procedural improvements. High planning predictability allows better usage of airspace and dropping some of today’s constraining factors. Efficiency improves by flying aircraft specific optimized procedures. By usage of sophisticated models and planning algorithms, total system’s performance will come close to global optimum. This paper describes a new and powerful way of modeling 4D airspace incorporating traffic, weather, restricted areas and any other objects existing/moving in 4D airspace. The model represents these objects in a way allowing very fast conflict detection and resolution in order to find a feasible and efficient global solution

City-ATM - Safe Drone Operations in Dense Traffic

The City-ATM project develops a simulation and demonstration platform for enabling unmanned flights in urban area. After the demonstration of an inspection of the Koehlbrand Bridge in Hamburg in phase 1, and a demonstration of dynamic geofencing to avoid hazard areas in phase 2 at the National Experimental Test Center for Unmanned Aircraft Systems in Cochstedt, the final project phase 3 concentrates on operating drones safely in dense traffic situations. Dense traffic will be achieved by some physical drones enhanced by many virtual drones, all crowding the same airspace

The 5th Dimension in Conflict Management – XYZT+Capability

4D-Trajectory-Based Operations promise improved efficiency, safety benefits, and high predictability. However, having in mind today’s heterogeneous traffic equipage, handling every aircraft identically seems unreasonable and inefficient. Aircraft with powerful anti-icing equipage are less sensitive against icing conditions than aircraft without anti-icing. Aircraft being capable of forecasting touchdown times with high accuracy can be handled more efficiently by arrival managers than poorer equipped aircraft. The risk potential of flying through ash clouds may even depend on current engine temperature. This paper presents a new way of handling conditional no-fly zones (NFZ) that depend on aircraft’s performance, equipage or capabilities. An already existing N-dimensional conflict detection and resolution framework usually handles separation violations in 4 dimensions, covering latitude, longitude, altitude and time. Conflicts are handled for all aircraft/aircraft and aircraft/NFZ combinations. This system is extended by (at least) one dimension allowing to model above described conditional NFZs. As for the other 4 dimensions, a distance metric is introduced for the capability dimension yielding a conflict if the aircraft/NFZ combination is not allowed in the given situation

Conflict Management for Large Scale Scenarios

An overview is given on DLR's unique CD&R capabilities. The talk splits into three sections: conflict detection, conflict resolution, and integration of procedures in the conflict management process

A Global Airspace Model for 4D-Trajectory-Based Operations

One of the key elements of the two major Air Traffic Management initiatives SESAR and NextGen is 4D-Trajectory-Based Operations. The main expected benefits are high predictability in advance, safety benefits, and improved efficiency. This paper covers the third issue: how can aircraft’s efficiency be improved? Obvious techniques like flying more direct routes, applying efficient departure procedures and gliding down to the runway using the continuous descent approach procedure are already widely investigated. Furthermore, taking advantage of new 4D-based concepts, other constraining and therefore inefficient limitations can be questioned, e.g., flying according to semicircular rules, disrupting climbs and descents due to crossing traffic, holdings and path-stretching dissolving too dense traffic, or flying constant flight levels although aircraft get lighter due to burning fuel. In addition, improving weather forecast and measuring systems provide further potential. Tailwind conditions can be used beneficially to save some extra fuel; thunderstorms might be taken into account already in the planning phase. Keeping in mind that each individual aircraft should be optimized to its own specific 4D trajectory, this isolated optimization would most certainly lead to conflicts. A global model of 4D airspace is necessary to ensure separation between all aircraft. Furthermore, each aircraft needs to separate from environmental constraints like thunderstorms and restricted areas. In the last two years, DLR’s Institute of Flight Guidance investigated how to build a model of global 4D airspace and its included traffic. The resulting system allows handling huge traffic scenarios in a very efficient way. It features modelling of 4D-trajectories and 4D-envelopes covering both restricted areas (e.g. temporary military restricted areas and moving thunderstorms) and the aircraft’s trajectories. The underlying algorithm subdivides dense traffic areas in smaller 4D-spaces to identify potential conflicts. Used on a dense traffic scenario containing 10.000 aircraft (i.e. one day above Germany), the algorithm reaches an average of 25 milliseconds on an off-the-shelf PC hardware to check if a given trajectory produces conflicts with other trajectories or objects. For the whole scenario, the algorithm needs less than 5 minutes to produce a list of all conflicts while using acceptable 1,5 gigabyte of memory. Since deletion of an object from the airspace model nearly takes no time, the proposed model is predestined to do fast trial-and-error based conflict avoidance regarding all environmental constraints (surrounding traffic, meteo, restricted areas …) at the same time. The global 4D airspace model, the underlying subdivision algorithms and results based on above mentioned traffic scenario are described in more detail in the paper