What is a net-centric system?
Net-centric, in its most common definition, refers to “participation as a part of a continuously evolving, complex community of people, devices, information and services interconnected by a communications network to optimise resource management and provide superior information on events and conditions needed to empower decision makers.” It will be clear from the definition that “net-centric” does not refer to a network as such. It is a term that covers all elements constituting the environment referred to as “net-centric”.
Exchanges between members of the community are based not on cumbersome individual interfaces and point to point connections but a flexible network paradigm that is never a hindrance to the evolution of the net-centric community. Net-centricity promotes a “many-to-many” exchange of data, enabling a multiplicity of users and applications to make use of the same data which in itself extends way beyond the traditional, predefined and package oriented data set while still being standardized sufficiently to ensure global interoperability. The aim of a net-centric system is to make all data visible, available and usable, when needed and where needed, to accelerate and improve the decision making process.
In a net-centric systems the quality of decisions is vastly improved as a result of decisions based on full awareness of the situation supported by quality data. In the ATM context, vastly improved controller decision making tools, safety nets and trajectory calculation are only a few examples of the benefits that can be realized via a net-centric system.
What is the difference between information sharing and information publishing?
System Wide Information Management (SWIM) implies that both users and generators of information share their data in a way that makes it available to those properly authorized to access it. Sharing is simply the conceptual activity that makes data available to authorized users. Publishing information is the act of letting authorized users know that certain information is now available for accessing and where the information is to be found.
In the SWIM environment it is not so that all information being shared is sent constantly from the source to all others. Instead, information that is to be shared is published and hence anyone who needs the information and starts looking for it will find it; alternatively, it is possible to subscribe to certain information and then the information is sent to subscribers immediately when it is published.
What is the scope of the information to be shared?
In legacy systems, the information to be exchanged is pre-determined and often hard-wired. A result of this is that adding new users, new destinations and new information is expensive and difficult. The SWIM environment that is underpinning the SESAR CONOPS does not make up-front decisions on what is to be shared and with whom. All information of concern to air traffic management is considered to be shareable information and as such, is published irrespective of who and where might want to use it. Obviously, access rights attached to the information ensure that only authorized users can get to restricted information.
The legacy definition if “aeronautical information” as it is defined in ICAO Annex 15 is being expanded to truly include all information that the ATM system needs and generates, including meteorological information.
It is the end-users who determine what they need for their activities and who then access the shared information without having to deal with the source itself.
The scope of such aeronautical information is upwards open and hence adding new elements is easy.
A frequent question is whether certain times associated for instance with a trajectory should or should not be shared. Based on the above clarification it should be clear that a decision on whether to share something is not dependent on the perceived usefulness or otherwise of the data concerned. Unless there is an explicit reason for keeping something secret, everything that is relevant must be shared. No second guessing of who will use what… that is for the end-users to decide.
What is the meaning of Trajectory Based Operations (TBO)? What is a business trajectory?
The existing air traffic management paradigm is airspace based. The ATM network is built on designated airspace structures into which the aircraft trajectories must fit. Furthermore, when aircraft are handled in real time, there is little knowledge of, and concern over, the trajectory beyond what is needed to ensure conflict free passage.
While an airline operates a highly tuned, precise network (planned trajectories and trajectories in the course of being executed), air traffic management uses what is a much abbreviated form of the trajectory descriptions (the flight plan) and acts on the resulting not too precise trajectory mainly on a here and now basis. Overall network effects of the interventions are taken into account only in the strategic and pre-tactical phases.
TBO is in many ways the opposite of the airspace based paradigm. Trajectories are considered as the expressions of the business/mission intention of the airspace user which is optimized for the operation of the aircraft, a business tool of great complexity. These trajectories are 4D (three spatial dimensions and time) and are flown with very high precision. Distortions to the trajectory are in fact seen as an inefficiency in the system if the distortion exceeds certain small margins (except direct separation or safety related distortions). Those who act on the trajectories, both human and automation, are required to consider the end-to-end effects of their interventions and they must act whenever possible in a way that minimizes the overall adverse effect. Airspace itself is created to enable the distortion free handling of trajectories, rather than being a source of distortion in itself (this is one of the most difficult to achieve aims of TBO). Obviously, trajectories must be negotiated between air traffic management and the airspace users when demand exceeds capacity. However, the negotiations are based on the principles embodied in TBO and trajectory ownership (see next question).
What is trajectory ownership?
When airspace users claim ownership of the trajectory, they are sending a powerful message to the designers of SESAR. Create us a system that can handle trajectories recognized as part of our networks with all the business sensitivity this entails; treat the trajectories as client resources handed over to air traffic management for safekeeping with minimum distortion; create a business environment in which the sophisticated business tools can be operated to maximum effect safely…
Clearly, a debate about how trajectory ownership would be handled in daily operations misses the point. In a properly constructed system for trajectory based operations (TBO), the effects of trajectory ownership become part of the system itself and are not things to be struggled with on a flight by flight, operator by operator basis. Where the need to negotiate trajectories is properly supported by information management (SWIM), the “there is no time” argument also loses its meaning.
Of course, ownership conveys obligations as well as rights. When airspace users claim ownership of the business trajectory, they must realize that as owners, they will have obligations to implement information management, integrate with the air traffic management network and play by the rules. This paradigm change will not come for free but all indications are that the benefits outweigh the costs.
Trajectory ownership by the airspace users must be one of the most important guiding principles of future system design. It is not a political dogfight but it can bite everyone if not implemented properly.
What is collaborative decision making?
Some people seem to think that collaborative decision making (CDM) is not much more than the partners coming together in person or on the phone to discuss things and hammer out agreements. No wonder so many think that CDM is suitable only for strategic decision making. This misconception is all the more surprising since Airport CDM (A-CDM) has shown what the concept can do. The same effectiveness is available in all phases of flight.
Collaborative decision making is first and foremost about achieving common situational awareness for all partners, based on the most complete and current, shared information available. This shared information enables decision makers to be aware of the impact of their decisions on their partners as well as their own operation. Obviously, in a modern, shared environment a collaborative decision can be taken even by a single partner!
Using the proper electronic tools, negotiating a trajectory between air traffic control and airline operational control is possible, even in the tactical phase of flight.
Such things are not done to-day but we should avoid projecting to-day’s practices into the future system or, even worse, try to envisage how future things would work in a system that has not gone through the required paradigm shifts. Both attempts would fail and lead us to conclude that certain things, like CDM, will not work. Future elements must be seen and tried out in future systems only.