Back to Air Transport IT Review - Air Traffic Management

The case for national and regional ATC networks

With Air Traffic Management undergoing rapid change in terms of both operations and technologies, and air traffic volumes growing steadily in many parts of the world, ANSPs face a range of options when it comes to managing the evolution of both ATM procedures and supporting CNS infrastructures.

Many new CNS applications require efficient and dependable digital networking. The production and exchange of flight data messages, NOTAMs, aeronautical messages, weather messages and so on are increasingly based on modern client/server or web technologies that demand efficient IP communications. Legacy messaging protocols such as AFTN are being converted to AMHS, which also needs an underlying IP network infrastructure.

In addition, surveillance data, whether produced by classical radar (en route, approach or ground) or by ADS-B stations, increasingly make use of standards such as ASTERIX, while efficient distribution of that data requires more advanced communication techniques such as multicasting.

While ATC voice (both air/ground or ground/ground configurations) is still considered the most critical communication flow in the CNS infrastructure supporting Air Traffic Control, the latest generation of voice communication systems and air/ground radios makes increased use of digital ground communications.

In the past, deployment of communication solutions was too often addressed on a case-by-case basis, where a new application would result in the commissioning of a new dedicated network and/or point-to-point leased lines. While this approach might have been initially justified by the need to phase investments and their associated costs, all too often the result is a complex and costly situation for ANSPs, with different application networks procured from different vendors, based on different technologies, and requiring their own highly specialized maintenance and training schedules and teams.

Leveraging the widespread benefits of IP

The advent of IP-based data communications and its global acceptance as a de-facto standard makes it possible for ANSPs to deploy a generic ground communication network that can serve as a common platform for all data flows supporting Air Traffic Control.

A ground IP network can be designed, deployed and validated to ATC standards, with the required level of dependability, availability and quality of service, and can be coupled with digital circuits supporting voice communications without compromising the criticality of these communications. Such a ground ATC network infrastructure makes it possible for ANSPs to streamline their procurement, maintenance and operation processes by benefiting from widely available COTS (Common Off The Shelf) products. In summary, a national IP network offers many important advantages:

  • Cost efficiency by replacing many dedicated low speed point-to-point links with an integrated state-of-the-art infrastructure based on COTS products
  • Increased quality and reliability through an optimized IP network topology and the automatic rerouting capabilities of a connectionless network protocol
  • Increased flexibility - adding, moving or removing users is far simpler on an IP network
  • Future proofing, as IP is the de facto international standard for modern networking
  • Scalability, because IP infrastructure capacity growth is virtually unlimited (For example, upgrading underlying physical low-speed cabling to optical fiber is transparent to end-user applications.)

SITA has acquired extensive expertise on the specification, deployment and commissioning of ATC IP-based ground networks for data flows and switched circuits for voice communications. In addition, SITA has proactively built a network of partnerships with key vendors in the area of IP networks and voice communication systems, enabling it to provide a single point of contact for all ATC ground network elements.

Extending IP network reach

At the international level, however, things are moving much more slowly. The result is that many ANSPs are using modern IP infrastructure for national communications but old fashioned point-to-point technology for international data flows. For the moment, for example, most ANSPs still manage dozens of low-speed analogue, digital leased lines or even VSAT links with each neighbouring country.

That's a pity, because it's a relatively simple matter to extend all the benefits ANSPs are reaping at the national level to international communications by migrating to regional IP backbone networks. From a practical standpoint, that means each ANSP replacing its international lines by dual access to the regional IP backbone to enable fast, flexible and reliable communications with all neighbouring ANSPs for data (flight plan, radar, OLDI/AIDC, NOTAM, etc.) and even voice communication.

In addition to the benefits outlined above, the use of regional IP backbone networks also facilitates migration towards regional/centralized ATC applications - for instance in areas such as AIS, AMHS and ATFCM - leading to further cost savings and enhanced continuity of ATC services across a region.

Regional IP backbone deployment can be implemented in several ways:

  • Outsourcing of regional IP services through common procurement. This model is being used to support PENS (Pan European Network Services). An RFP has been issued by EUROCONTROL on behalf of European ANSPs to carry all international operational voice and data communication flows between ANSPs and between ANSPs and EUROCONTROL (EAD and CFMU applications).
  • Subscription to the international IP backbone service of a global communication service provider such as SITA.
  • Deployment of a private IP regional backbone service.

Whatever choice ANSPs make, with so many cost and operational benefits the question is no longer whether to migrate to a national IP infrastructure and regional IP backbone service, but when.

Listen to article

Please, rate this page: