1. Required Total System Performance (RTSP) Bernard Miaillier EUROCONTROL
Agenda Item 3
Thank you…
Good morning…
I am ... and member of ATMCP.
The complete title of the presentation is: Need for the development of performance criteria and the concept of required total system performance (RTSP): It relates directly to the topics to be addressed under agenda item 3 of the Conference, but you will easily see connections with virtually all agenda items. Performance, including safety, provides a vehicle to discuss all aspects of Air Navigation from the planning stages to the monitoring of actual service delivery.
Required Total System Performance (RTSP) Bernard Miaillier EUROCONTROL
EUROCONTROL

2. Genesis of RTSP RCP, RNP, RSP Notion generalised to RTSP
Conceived within the FANS Committee
For CNS Performance Requirements
Notion generalised to RTSP
ICAO ATMCP tasked to investigate feasibility
Future ATM to be performance based (incl. safety) (see Agenda Item 1, WP/4 - operational concept )
Complex topic, initial work aimed at ANC/11
The notion of performance requirements was first conceived by the FANS Committee when it addressed the Communication, Navigation and Surveillance systems and tried to dissociate the actual needs in terms of functionality and quality from the existing or candidate technologies.
The notion was then further generalised as RTSP by the Air Navigation Commission which saw the potential for a wider use, for the “total system”.
The ANC did not enter into detail and tasked the ATM Operational Concept Panel, ATMCP, to investigate the feasibility of the concept.
The panel, as the first presentation this morning has shown, came quickly to two key features of the proposed ATM operational concept: it should be performance based, and, while implying additional requirements regarding its management, safety is an integral element of ATM performance.
The panel conducted initial work on ATM performance; this is a complex matter, with many ramifications. The panel endeavoured to identify the different aspects of performance, their application and the work needed to clarify the issues.
This presentation is a snapshot of work done so far. Although the feasibility is not fully demonstrated, intermediate findings are encouraging and allow to confirm the importance of performance considerations for preparing the future ATM system.

3. Need for Performance Orientation
ATM serves society and air traffic stakeholders
Various expectations, safety comes first
Performance, always a reference:
“safe, orderly and expeditious flow of traffic”
Performance orientation trend in economy
Communicate on goals, achievements
Current and future requirements
Plans and actual levels
Support / facilitate decision making
Understand the effect of changes
To move system development from add-ons to goal driven
ATM serves air traffic and society at large. Stakeholders regularly express their requirements and expectations and make their satisfaction or dissatisfaction known when the expectations are met or not. The expectations vary depending on the nature of the stakeholders and the context of their activities. While safety is a component of performance, all agree that it is the overriding aspect.
In just a century of aviation, performance has always been an important consideration. In Annex 11, the traditional expression “safe, orderly and expeditious flow of air traffic” is an implicit reference to performance.
Nowadays, the economic activities served by ATM are increasingly discussed in explicit performance terms. The same results from the observed trends in ATM corporatisation and towards a more structured regulatory environment.
It is essential to be able to communicate on goals and achievements, and to assess and compare the present and the future, or plans and achievements, as well as an air traffic control unit and another one.
The objective is to support and facilitate decision-making, by understanding the effect of proposed changes, thus reducing project risk and being more convincing. This will allow to drive the ATM system development by goals rather than on the basis of adding new components to an existing baseline.

4. A Performance Framework to Structure Discussion
Three pillars
A hierarchy of ATM Performance Concepts
Accurate models of ‘what drives what’
e.g. cause/effect relationships between expectations, functions, system components, concept of use, architecture
Rigorous description of traceable performance parameters
An approach: ISO13236 Quality of Service Framework
Because performance is a complex notion that can apply to many things, ATMCP looked for a structured approach and proposed an explicit ATM performance framework that is based on 3 main pillars:
A hierarchy of performance concepts, to distinguish between problems of different natures. For example, overall safety, expressed in number of annual accidents, is not an issue at the same level as the capability of a radar to track a certain number of aircraft.
Models. To know what to do in order to obtain a desired effect or to predict the effects of proposed changes. For instance, how can more accurate information on future aircraft position used in automated tools improve ATC processes? How much can this improve safety, capacity or reduce system costs?
Finally, a rigorous description of the performance parameters of individual elements, in order to avoid ambiguities and have good control when dealing with the understanding or quantification of defined functional characteristics and the requirements placed on them. The ISO Quality of Service Framework provides such mechanisms.

5. Hierarchical ATM Performance Concepts & Models
Actual
Performance
Measurement
& Monitoring
Level 1: Political and socio-economic requirements
safety, security, environmental efficiency, costs, etc.
Level 2: RASP
safety, throughput, delay, predictability, flexibility, etc.
Level 3: RTSP
on operational functions/entities
set of characteristics
RfnP
Rf1P
The hierarchy of performance concepts identifies 5 levels. From one layer to the next there is a change in the focus, the type of representation, the level of abstraction, or the main stakeholders-customers-actors.
The first level addresses the political and socio-economic requirements on aviation. It includes the expectations of the various stakeholders, including States, airspace users. They are expressed in general terms of safety, security, etc.
The second level is closer to ATM. It has been called RASP (Required ATM System Performance). While the first level addresses aviation overall , Level 2 focuses on the contribution of ATM to the general expectations, and thus impacts on the mission requirements that will drive the development and the operations of the ATM system. ATM cannot take responsibility for the whole of aviation safety or all environmental improvements.
RTSP constitutes Level 3. It covers the overall performance of the ATM core system functions, like traffic synchronization. It relates to the performance of the ATM system functionalities that are implemented. Between Level 2 and Level 3 there is a fundamental change in the representation. It is the operational concept that defines how we can deliver safety and the other expectations out of a set of ATM functions, services, procedures and tools. It is not possible to deduce solutions from the expectations themselves without an operational concept in mind. Conversely, an operational concept can only be declared good if one can relate it to expectations.
Level 4 defines, in performance terms, the system requirements for information management, data processing or CNS operational services. Using an ATM architecture model, one can relate the performance of for example the communication systems to their use by the various operational functions of Level 3. This level allows to introduce for example RCP, and other possible performance requirements such as, possibly, the quality of the prediction of future aircraft position.
Finally, Level 5 deals with the specific technologies and methods to implement Level 4 and that will typically be found in technical standards and other similar products.
The right part of the diagram is a reminder that performance is not just a notion for the planning phase. It has to be measured and monitored by reference with set targets. One needs to ensure that expectations are met and that safety levels are being achieved and maintained.
The second pillar I mentioned, models, is also embedded here, these models allow to link 2 levels, or describe the contents of a level.
Level 4: System Requirements
for an airspace and/or type of users
sets of consistent enabler requirements, e.g. RNP, RCP, etc.
{ … }
Level 5: Standards & specifications (technologies)
tech. SARPs, MOPS, standards, ISO90xy, etc.

6. Quality of Service (QoS) Framework ISO 13236
Use for RTSP seems appropriate for
ATM system constituents, even operational services
they can be represented in terms of information processing
Describing underlying technical services
Main requirements covered by 4 characteristics
Delay - Transient responsiveness
Capacity - Throughput
Integrity - Accuracy
Reliability - Availability
Regarding the third pillar, the ISO Quality of Service Framework Document has been originally designed for communication systems. Its use for RTSP and the lower levels of the model has been investigated. The first results indicate that it would be appropriate, in particular because the ATM functions, even the purely operational processes, can generally well be represented in terms of information processing.
The main parameters describing the requirements could be covered by the 4 broad characteristics shown on the slide and basically related to the duration of the process, its productivity, its ability to do the right thing and its availability.
ATMCP started to develop some examples for ATM functions, but I will limit myself to a basic illustration regarding the 2 required performance parameters which are best known: RNP and RCP.
RNP has reached the implementation stage. The main characteristic of an RNP category is the navigation accuracy, to the point that RNP categories are denoted by their horizontal accuracy figure, like RNP 10, RNP 1, etc. Should it be necessary to specify other QoS characteristics in the future, like availability, continuity of service, integrity and alert delay, they could be accommodated.
For RCP, the basic definition is agreed. It comprises a 95% transit delay (maximum end-user-to-end-user transfer delay demanded for the transfer of messages), message integrity (probability that the communication system does not provide erroneous information) and reliability/availability (availability percentage, service outage rate, and outage duration). These 3 parameters fit perfectly with the model, although it is much less simple than in the case of RNP to summarise the classes with one figure like RCP25 or RCPx.
Illustration
RNP
navigation accuracy
RCP
95% transit delay
message integrity
reliability/availability

7. From Expectations to System Characteristics
Trade-offs, except for safety
Operational concept Scenarios
System architecture
RTSP
ATM System
RASP
Expectations
I would like to come back now on some of the considerations.
The performance hierarchy shows the important articulation between the RASP - Required ATM System Performance and the RTSP - Required Total System Performance. It is where we move from the perception of ATM seen as a black box to parameters inside that box. RASP addresses the outcome, RTSP the output of the ATM functions.
A general description of performance is not sufficient. What is essential in the performance oriented approach, is to be able to set targets and to measure, in an objective way. To this end the metrics that will qualify the requirements should be SMART, specific, measurable, accurate, relevant and timely.
It is never possible in reality to meet all individual expectations at the same time, especially in a very demanding context like aviation. Basically, 2 aircraft cannot be at the same place at the same time. Trade-offs or compromises will have to be found and agreed to maximise the overall satisfaction of the different stakeholders. However, in doing so, safety remains the overriding factor.
The framework is meant for a rather universal applicability, from the global to the local scale. The technical requirements have to be defined globally. However, even with the aim of a globally interoperable and seamless system, the RASP targets, their numerical expression are likely tied to regional or local conditions. It is the judicious selection and combination of implementation options that allows us to achieve the RASP targets.
This underlines the importance of having well defined descriptions of the operational concept, the operating conditions and scenarios, the services that will realise the concept, and the system architecture supporting them .
“SMART” Metrics
Global / regional / local targets Vs global standards

8. RTSP: an aggregate of ATM system component requirements
Describes the performance of the ATM Concept Components in a given environment
Adapted to local and user needs
Defined for most demanding characteristics
Not independent from available implementation options
balance between generic (to keep implementation flexibility), specific (to prevent proliferation of solutions)
Driven by most stringent requirements
likely: conflict management and navigation (real-time, safety related decisions)
Summed up by a few Categories only ?
A few more words on RTSP itself.
Expressed as combination of ATM system component requirements, it will represent a minimum set to satisfy expectations.
RTSP describes the performance of the ATM Concept Components in a given environment. It will be adapted to both the local and user needs. While consistent with the global concept, the solutions that suit a specific area are not necessarily the same as those of another area that may have different traffic density, traffic patterns, geographical characteristics and institutional arrangements.
One may be afraid that with all these particularities and the intrinsic complexity of ATM, one will never find common characteristics and will therefore be faced with an unmanageable situation that nobody understands or masters. In fact, it must be noted that while all relevant factors must be considered, it is sufficient to define RTSP for the most demanding characteristics of the environment under consideration. Also, while the elaboration of a solution is not independent from the available implementation options one should take care in creating a proper balance between what has to be generic (to keep implementation flexibility), and what can remain specific (to prevent proliferation of solutions). Finally, RTSP is in fact mainly driven by the functions with the most stringent requirements. These will likely be conflict management and navigation which involve real-time, safety related decisions.
This simplification is possible and necessary. It should however not create now the illusion that we will be ultimately able to reduce ATM to a few categories like those of RNP.

9. RTSP / Performance in ICAO Activities
Framework to facilitate co-ordination of individual contributions
Planning Tool
Global, regional or local: same model, consistency, harmonisation
For the target situation and the implementation steps towards it
Monitoring Tool
Against objectives, at appropriate level
Feed back is essential
So, what is the benefit for ICAO?
In addition to having definitions and a common terminology, a performance framework will facilitate co-ordination of individual contributions, making them fit better together and with more recognisable goals.
The performance approach and the RTSP concept provide a planning instrument. The shared understanding can be used at global, regional, sub-regional or local, and even inter-regional level, as appropriate, to plan and implement a fully consistent and harmonised ATM system.
This logic does not only apply to the long term vision, but also to the more elementary steps of the transition towards the vision and for which the actual implementation decisions are made.
RTSP is also a monitoring instrument, through the specification of metrics and targets. This will be done at the appropriate level.
A feed-back on achievements is essential to improve performance, not only in view of new investments, but also via benchmarking and dissemination of good practices.

10. Future Work Feasibility to be confirmed Define metrics
Further develop the framework
Distribute individual aspects to panels with an overall consolidation body
Keep momentum on SARPs development and planning
Priorities
Upper layers, definition of indicators/targets
Understand ATM system behaviour
As already said, it is proposed to address ATM performance with an unprecedented level of consideration. It should come as no surprise, there is still substantial work before this complex subject is mature and becomes part of the routine. In particular, the feasibility of the RTSP concept need be confirmed, not as the ability to define a myriad of parameters of various kinds, but as the ability to highlight a manageable number of significant key parameters for system design and monitoring, that can make global development and harmonisation efficient.
Work should address the definition of performance metrics and the further development of the framework itself. Regarding this aspect, the objective is to achieve a shared, deep system engineering understanding of ATM: what are the main functions? how, collectively, do the various requirements deliver against expectations? how operational functions need support by more technical functions?
It is suggested to distribute work to the relevant panels and groups that will address their area of competence, but it is essential to have an architect to ensure the overall consolidation and consistency.
Working more intensively on performance should however not distract efforts, and momentum should be kept on SARPs development and planning.
The first priorities are to progress significantly on the upper layers of the model, by defining, and agreeing on, metrics and targets, and to get a better understanding of the ATM system behaviour.

11. Agenda Item 3: Expected Discussion Outcome
WP/8: basis for discussion
Conference expected to
Support performance orientation for future ATM definition
Call for, and support, more work to
Formulate and define objectives/targets & metrics
Harmonise all contributions within an overall framework.
The outcome of the Conference on agenda Item 3 Performance is expected to be close to the recommendation in WP/8 shown here.
As already said, the global ATM operational concept, item 1.1, the enabling concepts, item 1.2, but also the planning considerations, item 1.3, cannot escape to be addressed with reference to performance expectations and achievements. The system safety approach discussed under Item 2, in addition to creating the conditions for safety to be delivered, also definitely involves safety targets, metrics and measurements.
So, the Conference is expected to progress on two main aspects:
first, give a strong performance orientation to the definition, planning, implementation, operations and review of the future ATM system;
second, trigger work in the area of performance, in particular to formulate and define ATM performance objectives, targets & metrics, and to complement the definition of the overall performance framework within which to harmonise all contributions and to which the concept of RTSP belongs.
I am confident that the discussions will be fruitful.
I thank you for your attention and wish full success to the Conference.