Sentinel – eye in the sky

It started life as a long-range business jet but the aircraft platform has been transformed. It’s still sophisticated but the emphasis is on technology, not style, for this is the RAF’s most advanced long-range airborne surveillance system.

The aircraft on the flightline at RAF Waddington in Lincolnshire, bears the badge of No 5 Squadron, and resembles a drably painted new Bombardier Global Express. But beneath the slate grey fuselage of the Sentinel R1, to give it its military designation, lie sensors that are at the heart of the RAF’s new Advanced Stand-Off Radar (ASTOR) system.

ASTOR will provide long-range, battlefield intelligence, with target and tracking imagery and information for the RAF and the Army. The system comprises three basic components – the airborne platform that carries the radar system, two transportable ground stations to support a deployed headquarters and six mobile ground stations to support army units on the battlefield.

In a perfect example of inter-service co-operation, the Sentinel R1 aircraft, powered by Rolls-Royce BR710 engines, provides a flying office for a three-strong Army/RAF mission crew that operate the sophisticated radar system and analyse the data. This system enables all-weather, day and night reconnaissance and surveillance to be undertaken from a range of several hundred kilometres, while also allowing the operators to monitor the activity of mobile ground targets. This information is then downloaded in near real time via a wideband data link to the ground stations where it is analysed and presented to a battlefield commander – allowing him to see threats to his ground forces.

No 5 Squadron was reformed in 2004 as a specialist intelligence, surveillance and reconnaissance RAF squadron with the specific aim of bringing ASTOR into service. It took delivery of the first of five aircraft in March 2007 and, following an intensive training period, recently had the opportunity to test out this exciting new capability in the harshest environment of all – frontline operations in Afghanistan.

The aircraft was found to operate well in the hot and dry conditions and had no problems climbing to high altitudes at maximum power. As well as the thrust performance, the Rolls-Royce BR710 engines also provide a lot of the electrical power for the radar systems.