The PARTAKE project is aligned with the SESAR JU H2020 EXPLORATORY RESEARCH and the European ATM Master Plan strategy which is the main planning tool for defining Air Traffic Management (ATM) modernisation priorities and ensuring that the SESAR (Single European Sky ATM Research) Target Concept becomes a reality and drives forward the need for high performing aviation systems for Europe.

 

SCOPE

PARTAKE focuses on improving the air traffic dynamic demand capacity balance by using   means of the prompt identification of proximate events at network level, the re‐adjustment of take‐off times within the assigned nominal Calculated-Take-Off-Time (CTOT) margins and the rearrangement of departing sequence of aircraft at the involved airports to minimize the amount of ATC interventions. It can be considered as short term Air Traffic Flow and Capacity Management (ATFCM) measures, applied at local level and reducing traffic peaks for the whole European airspace.

This project contributes to the research topic Trajectory Based Operation (TBO) that enhances the design of new Decision Support Tools (DST) that could deal with present demand or capacity balance in Air Traffic Management (ATM) relying on a technological framework for information sharing (SWIM). The main TBO challenge PARTAKE is facing is to reach a conflict-free robust set of Reference Business Trajectory (RBT) just by introducing small temporal adjustments. PARTAKE is using the TBO approach preserving the 3D components of the Reference Business Trajectories (RBT’s) but adjusting the time component by means of micro-ground delays, providing a new smart mechanism to support conflict resolution (CR) collaborative-competitive tools with minimum ATC interventions.

The following milestones are aligned with the PARTAKE project:

 

project

 

APPROACH

The vision of the PARTAKE project is to enhance TBO as a flexible synchronization mechanism that will support an efficient and competitive use of the ATM services based on an intelligent cooperative combination of the time stamp component of the RBT agreed by the AU’s. The core research activities in PARTAKE are geared toward “system thinking”  in which a holistic approach to resolve conflicts at tactical level is used considering both the strategic and operational constraints. .

 

To achieve this, the project is focusing on three main innovation strands:

 

  • Enabling vertical connectivity between the Air Traffic Flow Management (ATFM) and the complexity of the traffic at hotspots
  • Enabling horizontal connectivity between AU’s business models and ATM sustainable competitive services
  • Creating an easily extendable and adaptable robust cooperative DST dealing with feasible time stamp agreements considering the TBO interdependencies

 

In PARTAKE, pre-flight RBT’s (at departure) and en-route RBT’s (network scope) are mapped into micro-regions (trajectory scope) to identify interdependencies and compute feasible clearances to relax tight interdependencies while preserving ATFM TTA and departure slot time constraints. The models to identify the tight trajectory interdependencies will be specified in Coloured Petri Net formalism for an efficient causal analysis while the time stamp control will be evaluated in Constrain Logic Programming. A service oriented architecture (SOA) will be used to implement the interface with SWIM while agent-based technologies will be deployed to evaluate in a simulation environment the acceptability of the solutions by the ATM stakeholders.

 

METHODOLOGY

The vision of the PARTAKE project is to enable TBO as a flexible synchronization mechanism that will support an efficient and competitive use of the ATM services based on an intelligent cooperative combination of the time stamp component of the RBT agreed by the AU’s. To achieve this, the project is focusing on the following innovation strands:

 

1. Tight trajectory interdependencies: Mitigating adherence problems due to ATC directives.

In PARTAKE, 4-dimensional trajectories (4DT) are considered as a precise description of an aircraft path in space and  time which includes the ”centerline” of the path, using Waypoints (WPs) to represent specific steps along  the path, together with appropriate buffers to describe the associated position uncertainty. The path contains altitude descriptions for each WPs and suitable indications about the time(s) at which the trajectory will be executed. Some of the WPs in a 4DT path may be associated with Controlled Time of Arrivals (CTAs). Each CTA is defined by a Target Time of Arrivals (TTAs) requirement that must be met by the aircraft within a specified time tolerance. Therefore, CTAs actually represent time ”windows” for the aircraft to cross specific waypoints and will be used to improve the clearance between aircraft at identified concurrence events.

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Detection of Tight Trajectory Interdependencies

 

2. Gap Analysis of time stamp combinations to improve time clearances

A causal model is used to analyse the RBT’s interdependencies quantified by the temporal looseness. Tight interdependencies (i.e. loose of separation minima) can be relaxed by a small adjustment of the Calculated Take-Off Times (CTOTs) of the involved aircraft preserving the TTA and the slot assigned at strategic level. In most airports, aircrafts are queued at the runway threshold and dispatched using a First-Come-First-Serve (FCFS) policy. This policy is justified due to a lack of tools and relevant information that could analyse the downstream impact of different sequencing departures on saturated sectors.

 

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PARTAKE re-prioritizing the initial departing sequence to mitigate hotspots

The list of potential concurrence events identified in the previous process allows the specification of time constraints required to formalize all potential occurrence events in the network. The time domain of the departure slots can provide a clearance window of 15 minutes which PARTAKE will analyse by the means of a Constraint Programming model the feasible combinations of feasible CTOTs for those trajectories which causes tight interdependencies and propose the right time departure combination which maximize clearances considering downstream effects (ie. emergence of new interdependencies in other sectors).

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Resolution of tight trajectory interdependencies using slight speed changes. The trajectory is modified by shifting S1’ according to the applied delay on the CTOT to avoid the first concurrence event while shortening S3’ in time by a slight speed change in order to avoid the second concurrent event and preserve the TTA.

 

3. Improving adherence robustness through relaxing some non-relevant time stamp contracts

Tight interdependencies enhances the propagation of perturbations, thus, the effects of a poor time waypoint adherence in a high density sector can generate a huge amount of changes in the rest of the trajectories, whereas poor time waypoint adherence in those sectors without tight interdependencies do not create side effects. There are few sectors in Europe with tight interdependencies, which allow adjusting waypoint time-stamps in those areas with a low occupancy factor and negligible soft interdependencies. Thus to preserve time stamp agreements at tight waypoints, it is possible to relax time stamps in some areas to compensate the effect of potential uncertainties (departure time uncertainty and cruise speed uncertainty) or to extend the functionality provided by calculating the CTOT.

4. Dynamic, multi-objective optimization model to support AU’s business targets.

ATM metrics such as Traffic Density, Peak Load, Occupancy and Number of Conflicts will be evaluated in each sector based on the AU’s trajectories and the PARTAKE trajectories to synthesize performance comparative indicators at micro level, so the different stakeholders will be able to check the benefits partaking with the developed tools.

PARTAKE PROJECT