Sharing the Picture

RAF Boulmer Guardian Workstations
Guardian workstations are seen here at RAF Boulmer. Guardian is being upgraded with the Link-16 TDL replacing the erstwhile Link-1 tactical datalink the RAF has relied on in the past to share the UK’s RAP with NATO.

New incarnations of the Royal Air Force’s Guardian integrated air defence system command and control architecture will be upgraded with NATO’s Link-16 communications protocol.

The Royal Air Force’s (RAF’s) Guardian Command and Control (C2) system forms an integral part of the United Kingdom’s Integrated Air Defence System (IADS). The IADS is tasked with protecting UK airspace and air approaches. Guardian receives imagery from several ground-based air surveillance radars positioned around the country. This imagery is consolidated to form the UK’s national Recognised Air Picture (RAP). Should un-cooperative air targets be detected, RAF Eurofighter Typhoon F/GR4 combat aircraft are scrambled to intercept them. RAF officials told delegates during IQPC’s recent Military Radar conference, held on 28th and 29th June in London, that the IADS performs two distinct, but overlapping missions: As well as supporting the general air defence of the UK, the IADS has a counter-political violence mission. RAF jets will intercept, and if necessary, attack aircraft performing suicide missions against targets in the air or on the surface. The RAF’s IADS coverage forms part of the North Atlantic Treaty Organisation’s (NATO) Air Policing Area-1 (APA-1). APA-1 also includes Norwegian and Icelandic airspace.

Project Guardian

Guardian replaced the RAF’s previous UK Air Surveillance and Control System’s C2 architecture known as UCCS. The Guardian architecture comprises the computer hardware, software and networking underpinning the C2 system. In 2018 IBM was awarded a contract to replace UCCS with Guardian.

A senior RAF official told delegates that Guardian is now in service. The architecture is based at RAF Boulmer, northeast England. The C2 system is also replicated at Swanwick in southern England, home to the London Area Control Centre (LACC). LACC controls the airspace above London and much of the UK, working closely with other control centres around the country. The RAF facility at Swanwick enables coordination between civilian and military controllers, particularly for the counter-political violence mission.

Guardian is being delivered in two increments. Increment-1 has already been delivered and the RAF is looking ahead to Increment-2. Increment-2 is expected to reach full operational capability by 2024. Among the enhancements Increment-2 brings to Guardian is NATO’s Link-16 Tactical Datalink (TDL) protocol. Link-16 will be used to share Guardian’s tactical data with NATO’s wider Air Command and Control System (ACCS). ACCS is a scalable air C2 system being implemented across most of NATO’s European membership. Disparate ACCS systems share their RAPs with NATO’s Combined Air Operations Centre (CAOC) at Uedem, western Germany. The CAOC is responsible for air policing across alliance airspace north of the Alps, as far east as the Baltic and as far west as Iceland. NATO air policing south of the Alps is controlled by the CAOC at Torrejon airbase outside Madrid, Spain.

Vintage Datalinks

The RAF currently uses NATO’s Link-1 TDL to share data into the NATO CAOCs, however RAF officials speaking at the conference said this is restricted to sharing track information, unlike Link-16. The latter shares tactical information via so-called ‘J-Series’ messages, alongside track data. Link-1 is a ‘vintage’ datalink, having been developed by NATO back in the 1950s. According to official NATO documents, Link-1 moves data point-to-point across telephone lines at data speeds of 1.2 kilobits-per-second/kbps. It has no Electronic Counter-Countermeasures (ECCM) protection, although this is less of a concern as the link is not using radio. Link-1 was widely used across NATO to connect national IADS C2 systems to enable them to share tactical information.

Link-16 will be a step change for Guardian. Using frequencies of 960 megahertz/MHz to 1.215 gigahertz the TDL can move data at speeds of up to 57.6kbps. Boasting good ECCM protection, Link-16 has no single point of failure and can host hundreds of subscribers on its networks. The TDL also provides voice communications and shares J-series messages. These messages are used for everything from mission management, weapons coordination, air control, electronic warfare and navigation, to search and rescue and even meteorology.

The addition of Link-16 to Guardian is an important enhancement further improving both the UK IADS C2 system and NATO’s ability to coordinate air policing. NATO faces heightened tension across its European membership because of Russia’s actions in Ukraine. Guardian’s improvements send a deterrent message to Moscow that the alliance is closely monitoring its airspace and is ready to respond to any aggression.

UKADGE Radar Coverage
This diagram gives a rough indication of the coverage provided by the ground-based air surveillance radars feeding imagery into the RAF’s Guardian integrated air defence command and control system.

by Dr. Thomas Withington