To optimize safety and cost structures and improve air traffic control services, air navigation service providers (ANSPs) are seeking solutions that will enable them to share resources for air-ground and ground-ground communications between centers. They are even going one step further by defining independent centers as backups for each other. That way, if catastrophic events occur at one center, the backup center can take over the disabled facility’s communications operations, using unaffected airground and ground-ground resources.
The challenging part of this approach is providing access to every air-ground and ground-ground resource in normal operations as well as in joint operation scenarios. Furthermore, it is important to keep the system configurations aligned between the centers involved.

Technology leadership

“ATC in the secure and trusted cloud” is already a reality with the R&S®VCS-4G voice communications systems. The challenges facing geographically distributed VCS installations can be well addressed by deploying an IP-based communications infrastructure. the R&S®VCS-4G addresses the challenges such virtual center installations are facing.


Resource sharing

EUROCAE ED-137 standard specifies the use of IP for voice communications in ATC environments. In particular, it defines the interface between the VCSs and radios and between VCSs. Furthermore, it specifies how several VCSs can access the same radios, including the relevant priority concepts in order to ensure reliable operation at all times.On the basis of this standard and the underlying IP infrastructure, voice communications systems can address any air-ground and ground-ground resource from different regions, even when one facility is not operational.

Reliable communications

Each center has to be aware of the current system configuration and of any changes in the air-ground and groundground resources that have been made. Using well-established, intelligent IP mechanisms, VCSs can align their system configurations even when one center had been offline for a while. Having two identical systems that are located several thousand kilometers apart but have access to all air-ground and ground-ground resources boosts the overall availability of the voice communications network: a complete outage at one facility will not affect operations at the other location. If one facility fails, the second center can access unaffected communications assets to ensure continuation of the disabled ATC facility’s communications.

Secure communications

Whenever VCS networks are closely linked, network security becomes crucial. Well-established, intelligent IP mechanisms can be used to control how resources access the system. While these mechanisms have proven themselves in public and private telecommunications installations around the world, isolating the ATC communications infrastructure from public networks and running it as a closed infrastructure is still the most secure solution.
Due to its full IP system architecture and distributed infrastructure, the R&S®VCS-4G is perfectly suited for integration into a virtual center.


The air navigation service providers of Iceland (ISAVIA) and Ireland (IAA) selected Rohde & Schwarz as sole supplier of their new ATS voice communications control system (VCCS). ISAVIA and IAA plan to operate a virtual control center to connect their Gufunes and Ballygirreen locations.
Rohde & Schwarz will deliver two fully IP ED-137 compliant R&S®VCS-4G voice communications control systems as well as HF receivers from the R&S®M3SR Series4100radio family. The systems will be used to provide communications services, including HF, VHF, SELCAL and SATPHONE, in the Reykjavik and Shanwick oceanic control areas (OCA).
The R&S®VCS-4G solution will consist of two independent systems. One will be located in ISAVIA’s COM center in Gufunes, Iceland, and one in IAA’s COM center in Ballygirreen, Ireland. The direct link between the two voice communications systems allows advanced scenarios, such as resource sharing for air-ground and ground-ground assets and a virtual center setup.
The concept of a virtual center makes it possible to operate the VCCSs either independently in standalone mode or in joint operations. As a result, operators have access to all resources and functions of both VCCSs. In the event of a catastrophe, such an advanced virtual center approach ensures operational continuity by reassigning resources within a supporting infrastructure to mitigate consequences. In a failure situation, the second center will be able to access unaffected assets (e.g. remote airground resources) and take over the disabled ATC center’s communications operations.

System overview
  • TR&S®VCS-4G controller working positions
  • R&S®VCS-4G server infrastructure
  • R&S®Series4100 radios
  • Interconnection to analog and VoIP radios from different suppliers
  • Interconnection to analog telephone lines and ATS-QSIG lines to neighboring ACCs
  • Rohde & Schwarz antenna switching unit
  • Communications infrastructure