Five is alive!

Gary Parsons reports from RAF Waddington as 5(AC) Squadron officially stands up with the RAF's latest system, ASTOR

5(AC) Squadron may have been reformed back in April 2004, but it wasn't until 6 June 2007 that it officially accepted its first of five Sentinel R1 aircraft, together with its standard. A milestone achievement in the ASTOR programme, it signifies the maturing of the development programme, with training for operational service now the primary objective.

In December 1999 Raytheon Systems Ltd was awarded a £800 million ($1.2 billion) contract for the development of the MoD Airborne Stand-Off Radar (ASTOR) programme. The system is an airborne battlefield or ground surveillance radar system for operation with the Royal Air Force and the British Army. The system is able to monitor and accurately locate activity over a large area, providing theatre commanders with information about the disposition of forces on the ground. It achieves this by employing a high-altitude airborne radar platform able to operate away from the immediate area of interest, during day or night, irrespective of the weather conditions. ASTOR can be summarised as providing twenty-four-hour, near real-time, all-weather, long-range surveillance and target acquisition of fixed, stationary and moving targets. Or, put quite simply, 'Getting the right information, to the right person, at the right time'.

On parade

The ability to identify moving and fixed targets under any conditions is now of utmost importance. Operating in a dispersed environment, under tight rules of engagement, also creates a requirement for positive identification, precise target engagement and accurate and timely information on targets and their surroundings. ASTOR provides an enduring capability that has utility in a wide range of operational scenarios, from humanitarian relief to combat operations.

The trend toward expeditionary operations has increased since the end of the Cold War; ASTOR is an inherently flexible and adaptable system, designed to be highly deplorable in modules sized according to the requirement. The people who operate ASTOR are also a unique asset - 5 (Army Co-operation) Squadron is a truly jointly-manned RAF Squadron including Army and Royal Navy personnel. Of the 300 squadron personnel, some 160 are air force, 140 army and three from the navy.

The first of the five Sentinel aircraft made its maiden flight in May 2004, the second in July 2005. Three Sentinel aircraft are taking part in formal flight testing in Greeneville, Texas, prior to being delivered to the RAF by the end of 2007. Final deliveries are planned for 2008, with full operating capability in 2009. Based upon the Bombardier Aerospace-Short Brothers Global Express aircraft, an ultra-long range business jet, the Sentinel has been modified to accommodate the radars and communications systems required by ASTOR. These include a canoe-shaped radome under the forward fuselage to house the radar antenna, a radome on the upper fuselage to house the SATCOM antenna, a 'bullet-fairing' extension on the vertical stabiliser and delta fins under the aft fuselage. The aircraft will operate at an altitude of 45,000 ft in order to achieve the maximum ground radar surveillance coverage and has a range of 6,500 nm together with a mission endurance of over fourteen hours. The engines for the ASTOR aircraft are the same as those deployed on the Nimrod MRA4 aircraft - each Rolls-Royce BR710 two-shaft turbofan engine produces 14,000 lbf to 17,000 lbf (63 kN to 76 kN) flat rated take-off thrust.

With equipment now in the hands of the Squadron, the process to develop the operational air and ground training package has begun. As this is the first time that the UK has benefited from a capability such as ASTOR, the complex training devolvement package is expected to take the reminder of 2007, but when made, will produce the first two operational air and ground crews and achieve to the Programme milestone of 'In Service Date' (ISD) in early 2008. Initial Operational Capability and then Full Operational Capability, which will see the Squadron at its full complement of personnel, equipment and training, is expected towards the end of the decade, when eight crews will be combat ready.

The ASTOR system is supported by a ten-year support contract from the Prime Contractor, Raytheon, and has a mature roadmap to allow progressive increases in system capacity should the wider defence environment dictate the need for change. In normal operations, the Sentinel aircraft will be linked with one or more ground stations, passing information by data-link for exploitation by the ground operators. The Tactical Ground Stations are installed in shelters mounted on Steyr Pinzgauer trucks and take about half an hour to prepare in the field. 5(AC) Squadron has already taken ownership of most of the Ground Segment, comprising six Tactical Ground Station and two container-based Operational Level Ground Station systems.

The aircraft will operate at a stand-off range from the target area, flying extremely high above the surveillance area. The ground stations will be located close to the units being supported and will move with them. Synthetic Aperture Radar (SAR) images can be exploited both on the aircraft and in the ground stations before being passed to intelligence staffs and commanders to aid their decision-making. Similarly, Moving Target Indication (MTI) data can be passed to the ground stations to add to the intelligence picture. The SAR operates in spot mode to identify and track specific targets or can be switched to swath mode which provides a large number of strips of pictures which join to form a detailed image of the battlefield. The radar is an upgrade of the Raytheon ASARS-2 side looking airborne radar used on the U-2. The radar operates at high altitude and in all weathers to provide high resolution images. ASARS-2 has been reported to provide images of the battlefield at ranges of 160 km, at altitudes up to 47,000 feet.

The Sentinel can also operate in an autonomous, 'untethered' mode, without ground station support. In this mode, the aircraft would exploit the data on the aircraft, or collect and store imagery and GMTI data on-board, for subsequent exploitation. This might be by data-linking the information to a ground station when within line-of-sight range, via Satellite communications for Squadron Based personnel to exploit, or for post-flight exploitation at the MOB or at a DOB.

Once the radar information has been gathered and processed, it can be passed by a wide variety of means for use both within the ASTOR system and more widely at all levels of command of British and Coalition Forces. It can be passed via datalink to other Information, Surveillance, Targeting and Reconnaissance (ISTAR) airborne platforms, such as the JSTARS or AWACS aircraft and the Sentinel can pass the information directly to US Forces JSTARS Common Ground Stations.

Raytheon has been responsible for establishing and building the entire ASTOR complex at Waddington, annexed to Hangar 3 on the 'waterfront', including both the Squadron headquarters as well as the sophisticated training facility itself. In addition to classrooms, offices and student rest facilities the complex includes a Training Equipment Hall and a range of advanced training aids including a Fixed Base Flight Crew Trainer, Rear Crew Trainer, Ground Station Crew Trainer, a Target Generator and Radar Simulator, and a Mission Interface Simulator.

"We've done extensive work to date and built foundations for the future", said Wing Commander Bill Hughes, the outgoing Officer Commanding on 6 June. Despite accepting the squadron's new standard from the Chief of the Air Staff, Bill only had a few days left in charge of the squadron - he took charge of the squadron on 1 April 2004 when it was reformed and handed over command to Wing Commander Mark Kemsley on 8 June, although with some regret that he was leaving without seeing the squadron operational. "It truly is a groundbreaking programme", he said, "and I'm delighted with the heritage that 5(AC) Squadron brings." The squadron's roots are in army co-operation over the trenches of the Great War, so it is quite fitting that it now serves once again as the 'Eyes of the Army'.

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