Trajectory Based Operations (TBO)

Specific challenge: Trajectory Based Operations (TBO) is a key element of future ATM operating concepts. It is expected to provide the flexibility needed by airspace users to optimise their operations while simultaneously ensuring the predictability needed at ATM network level for maximum overall performance. TBO starts with pre-departure planning and continues through to real-time air traffic control. One of its foundations is improved trajectory information sharing so it defines an approach for coordinating trajectory changes and constraints. It also sets forth the extent to which trajectory adherence is required to support the specific functions of the layered planning approach upon which the ATM network is built.

Scope: Research is needed to explore a number of fundamental questions related to TBO. A framework is required that can model a system combining trajectories emanating from multiple and diverse airline users and feeding into the different ATM functions at different layers in the network. In this way it should be possible to establish a theoretical optimum and to determine the sensitivity of the system to variations and perturbations. While it may be relatively straightforward to identify an optimum for a single airline (prioritisation based on inter-flight constraints, airframe dependencies, crew and so on) the combined system-wide view is far less obvious and highly complex, especially taking into account different degrees of collaboration or, in the real world, competition between airlines.

In developing the theoretical framework the challenge of defining an approach that can lead to the best outcome in practice should also be kept in mind. To what extent can a solution be constructed from pre-agreed criteria, when and to what extent does it require active coordination between the various stakeholders? How much should the system be automated taking into account requirements for resilience, what kind of algorithms should be implemented? How much predictability is needed to make the system work and what are the expected benefits from it?

Projects will find solutions that balance flexibility and the requirement for trajectory conformance. They must consider convergence and stability, analysis of non-linear phenomena in multi-user real-time communications, emergent behaviour and non-determinism, as well as error propagation. The chosen approach must allow convergence to a stable and robust set of trajectories, taking into account inherent uncertainties in all parts of the ATM system. Projects may further investigate the extent to which flexibility is desirable by comparing system-wide and airline-specific performance that can be achieved relative to a system that requires rigid conformance with pre-planned trajectories.

It is anticipated that research in this topic will emphasise modelling approaches rather than real-time human-in-the-loop simulation.

Expected impact: TBO is a key part of future concepts (SESAR, NextGen, ICAO). It is therefore essential to fully understand the benefits and limitations of the approach. This is particularly true since the technology needed to support TBO could be extremely costly. A clear understanding of the real benefits and operational application of TBO techniques can help direct further research in this area.

Type of action: SESAR2020 Research and Innovation Action (RIA)

Further conditions related to this topic are provided in the Technical Specification of the Call.