ATS SYSTEM GENERATIONS OF DFS IN THE SESAR CONTEXT

DFS Deutsche Flugsicherung, Germany’s air navigation services provider, introduced its new air traffic services (ATS) system P1/VAFORIT at Karlsruhe upper area control centre (UAC). January 2011 saw the successful conclusion of the initial operations phase

With more than 1.3 million flights in 2010, UAC Karlsruhe is one of the busiest control centres on the European continent. It manages en-route air traffic over central and eastern Germany.
P1/VAFORIT replaces a mainframe-based system called KARLDAP, which had been in service for more than 30 years. The new system represents a paradigm shift in flight data processing. It is based on four-dimensional trajectory prediction and stripless operations. Such trajectory-based systems are the core of the Single European Sky ATM Research Programme (SESAR). They provide four-dimensional data about the planned flight paths of all flights relevant to a control centre. These features aid air traffic controllers in anticipating and resolving possible conflicts between aircraft and make flight planning more accurate, thus improving punctuality and reducing the number of re-routings.

Key features of P1/VAFORIT are:
• 4D Trajectory Prediction
• Advanced controller tools, such as Medium Term Conflict Detection (MTCD), What-If Probing and Flight Conformance Monitoring Aids (MONA)
• Stripless operations
• Automatic centre « centre coordination (OLDI 4.1)
• Equipped for controller/pilot data link communications (upgrade in 2011/2012)
• Two fully dissimilar radar data processors (RDP): a dual-redundant primary RDP plus a dual-redundant fallback RDP (PHOENIX including redundant display processors)
• Mode S processing
• Short Term Conflict Alert (STCA) and Area Proximity Warning (APW)
• Synchronised Voice and Video Recording and Playback (VRAP)
• Modular client/server system architecture
• Up to 120 controller working positions (CWPs)
• Concurrent processing of up to 1,500 tracks and 1,500 flight plans
• Fulfilment of all relevant EU interoperability regulations

The implementation of the P1/VAFORIT system is part of the multinational iTEC (interoperability Through European Collaboration) programme of DFS and its UK and Spanish counterparts, NATS and AENA, together with Indra as their technology partner. The purpose of this programme is to improve interoperability between ATS systems of different countries. It also complies with the objectives established by the Single European Sky ATM Research Programme SESAR.
Ralph Riedle, managing director of operations at DFS, said: “The introduction of P1/VAFORIT with its trajectory-based flight data processing system is not just a step into the future. It is a quantum leap. From a technological perspective, DFS has paved the way for the route to SESAR.”
Marcial Bellido, DFS Programme Director at Indra, concurs, saying: “Karlsruhe has become a cutting-edge centre incorporating a 4D trajectory management model. With the P1/VAFORIT system that Indra developed to the standards set by DFS, the company has moved years ahead of the rest of the ATM technology companies. The new system offers more flexibility in choosing the most suitable route, which reduces flight time, fuel consumption and CO2 emissions. It will help air traffic controllers solve possible conflicts between aircraft in advance and will make flight planning more accurate, thus improving punctuality. The system will really assist DFS, as air traffic is expected to increase in the upcoming years in what is already one of the busiest areas in terms of traffic.”
“This first success is just one achievement within the cooperation agreement among DFS, AENA and NATS, which the Dutch LVNL has also recently joined, with Indra as technology partner. This agreement, the iTEC programme, seeks to achieve more interoperability among European countries and enables these countries to jointly align themselves with the SESAR goals.”

The SESAR Consortium has achieved agreement on the 2020 ATM Target Concept. Work to date suggests that it is sufficiently promising to justify continuing the SESAR Definition Phase. Further validation and development of the ConOps will take place as part of the SESAR Development Phase.
Fundamental to the entire ATM Target Concept is a ‘net-centric’ operation based on:
• A powerful information handling network for sharing data
• New air-air, ground-ground and air-ground data communications systems
• An increased reliance of airborne and ground-based automated support tools

High Density En-route/Approach ATC Target Architecture
The foundation of the ATM Target Concept is trajectory-based operations. A trajectory representing the business/mission intentions of the airspace user, which integrates ATM and airport constraints, is elaborated and agreed for each flight. This results in the trajectory that a user agrees to fly and the ANSP and airport agree to facilitate. Trajectory-based operations ensure that the airspace user flies its trajectory close to its intent in the most efficient way, minimising its environmental impact. The concept has been designed to minimise the changes to trajectories and to achieve the best outcome for all users. In that respect, user preferred routing will apply without the need to adhere to a fixed route structure in low/medium density areas.
The airspace user owns the business trajectory (BT) and has primary responsibility over its operation. Where ATM constraints (including those arising from infrastructural and environmental restrictions/regulations) need to be applied, finding an alternative BT that achieves the best business/mission outcome within these constraints is left to the individual user. This is agreed through CDM (Collaborative Decision Making) process. The owners’ prerogatives do not affect ATC or pilot tactical decision processes.
The business/mission trajectories will be described as well as executed with the required precision in all 4 dimensions.
iTEC will be a trajectory-based FDP system. It includes requirements for the creation and maintenance of several different predicted trajectories for each flight based on the needs of the functions and tools that support data distribution, ATC planning of traffic flows and individual trajectories, co-ordination, conflict detection, clearance conformance monitoring, arrival management and conflict resolution.
iTEC includes the use of data down-linked from aircraft (via Mode S or AGDL) or sent by the aircraft operator, but the requirements for this are relatively immature as this capability was not expected to be generally available from aircraft or aircraft operator systems by the target FDP deployment date.
The reference to ‘cruise climbs’ comes mainly from the business aviation lobby, who would like to use this technique at levels that are generally above most other aircraft (e.g. FL400+). It is assumed that this can be facilitated without FDP system support at these levels. However, if the technique were to be employed at lower levels or if more aircraft operated above FL400, then a number of modifications to iTEC would be required in the area of trajectory prediction, MTCD (Medium Term Conflict Detection) and co-ordination support.
The sharing of trajectories between all the actors in the ATM system is a common theme in the SESAR ConOps: all communications and negotiations concerning individual flights are conducted on the basis the flight’s trajectory. The participation of the iTEC consortium in the ICOG/EUROCAE WG 59 Flight Object Server (FOS) work is the first and most important step in realising the technical means to achieve this interoperability. This ATC-ATC interoperability, including interoperability with CFMU, will enable many of the current procedural constraints that constrain user-preferred trajectories to be removed.
iTEC will be able to calculate trajectories for flights that intend to operate on a pre-defined route structure or on direct route segments that are independent of the adapted route structure and are delineated by WGS-84 co-ordinates. ITEC therefore has the essential requirements to support a user preferred routing environment, but such an environment can only fully be achieved when aircraft can negotiate trajectory updates in flight using air/ ground data exchange.
iTEC supports civil and military (GAT and OAT) operations and the trajectory-based tools that iTEC provides will facilitate the minimisation of segregation. Temporary Segregated Areas (TSAs) can be dynamically defined in the iTEC system and can be activated automatically according to a stored schedule or activated on an ad-hoc basis. The routes of aircraft affected by the TSA activation are automatically revised to avoid the area, but only if it is calculated that the flight would otherwise penetrate the TSA during the period of activity. As soon as the TSA is deactivated, the original routes of those diverted flights are re-instated.
ITEC also allows TSAs to be defined with variable dimensions, thus enabling the airspace segregation to be tailored to the activity planned for that day. However, SESAR further suggested the concept of dynamic moveable areas, where the TSA would have its own trajectory in addition to a volume. If this should become a firm operational requirement, then it would require some additional iTEC support.
iTEC-eFDP has an airport interface that is designed to support current operations. The SESAR ConOps describes a far greater degree of data exchange between ATM actors, and in this case between ATC (TWR, ACC and CFMU) airport operator and aircraft operator. SESAR describes this sharing of data as system wide information management (SWIM), an environment where data is ‘published’ by the current ‘data owner’ and can be accessed by, or automatically brought to the attention of, anyone with the appropriate access rights. This level of data sharing capability will take some time to establish. The ICOG/CFMU FOS work is clearly aligned with this SESAR goal, but the initial FOS concept will need to be expanded beyond ATC-ATC interoperability to include all the other ATM actors. In the interim, point-to-point data exchange between aircraft operator and ATC and between airport operator and ATC may well be necessary to capture trajectory update information.

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