After 18 months

The 4DCo-GC project is composed of 2 main phases, each ending with a simulation campaign. The project is still in its first phase and the consortium is actively preparing the first simulation campaign (C1) that will be held during the first week of July 2012.

During the first phase of the project, several topics were addressed in parallel:

  • Refinement of the 4D contracts concept;
  • Development of the simulation infrastructure;
  • Development of simulation modules;
  • Preparation of C1.

Refinement of the 4D contracts concept

A 4D contract is not a simple trajectory made of 4D-waypoints (conventional waypoints with an attached time constraint). Indeed, sufficient separation space should be maintained between the aircraft whereas freedom must be given to the aircraft for managing unforeseen events on its own. To reach these objectives, the definition of a 4D contract has been proposed: it is composed of 2 main elements: a 'bone trajectory' (basically a 4D trajectory) and margins (called "bubbles") around the aircraft.

The procedure for generating the 4D contracts was also defined, from the initial airlines demand to the 4D contract given to the aircraft using an iterative process.

Development of the simulation infrastructure

The main objective of the project is to assess the 4D contract concept using simulation. So, the simulation part of the work is of primary importance. To enable the various dedicated modules defined in the frame of the project to work together, a simulation infrastructure has been developed. In fact, this simulation backbone is composed of two infrastructures developed by Onera (HLA/IESTA) and DLR (DataPool) linked by a gateway. This enables the modules integrated on HLA and on DataPool to communicate with each other on a synchronized way.

Development of simulation modules

The overall integrated simulation is composed of several modules dedicated to specific parts of the 4D contract concept:

Generation of the 4D contracts (pre-tactical phase): The role of the pre-tactical phase is to prepare the initial 4D contracts for the whole simulation. So it must generate the 4D contracts in accordance to the airlines wishes (in terms of departure/arrival airports and time) and respect the airports capacity. They are then modified/adapted in order to ensure that the flights are conflict-free. The following modules are developed:

  • Definition of a realistic airline demand baseline
  • Calculation of optimal flight profiles
  • Conflicts detection and resolution
  • Arrival / departure optimization on airport
  • Aircraft ground movement planner (at airport)
  • Bubbles calculation and attachment to the 4D trajectories

Execution of 4D contracts, at the European scale (tactical phase): The tactical phase is on-line. Each aircraft is simulated and should fly its assigned 4D contract. The following modules are developed:

  • Aircraft models: performance, FMS, guidance
  • Contract compliance monitoring
  • 4D contract re-planning
  • Data link

Execution of 4D contracts, at the aircraft scale: in order to study and analyze the guidance and control aspects of the 4D contract concept implementation, it is necessary to have a close look at the aircraft. This is not possible at the global traffic scale, as the simulator uses simplified models of aircraft. This individual aircraft simulation is, on the contrary, based on detailed and accurate aircraft models: 6 Degrees of Freedom (6DoF) motion model and 4D-FMS.

  • Individual FMS
  • Individual aircraft motion
  • Self-generation of a local 4D contract (emergency management)
  • Data link

Preparation of C1

The main purpose of C1 is to make a first integration of the various modules on the simulations infrastructure, and to perform initial tests to ensure compatibility between the modules, assess the algorithms performance, etc. It is also an opportunity to disseminate the objectives and current status of the project. In this perspective, the goals of C1 are twofold: to explain the 4D contract concept and to get feedback to an external audience.

Two types of simulation scales are planned, each bringing different, but significant, inputs towards the general objectives of the project:

  • Global traffic: in order to have a global picture of the traffic at the European level and highlight the interactions between the ATS actors;
  • Individual aircraft: in order to have a close look at the aircraft guidance.

C1 will take place in Onera Toulouse premises during the first week of July 2012.

The final results of the 4DCo-GC project will have a potential impact on various areas. The first one will be to help promoting the European leadership in the field of the air transport.

Moreover, the project's results will provide inputs to the definition of systems enabling the more automated operation of the aircraft (ADS-B, ASAS, FMS, collision avoidance, health monitoring, etc.). A more efficient use of airspace using 4D contracts further increases the savings and sustainability garnered from more efficient travel, including the increase of time efficiency. At last, 4DCo-GC could clarify most of the questions around the term "4D business trajectory" - define the required precisions, estimate constraints, describe requirements to future planning systems and data links.

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Project Progress
Last update Thursday 27 September 2012