A Sample Feature From Aviation News

The Famous Five

The RAF is preparing to induct the Bombardier Sentinel surveillance platform into service and on June 6, a new standard was presented to the user squadron, No 5 at RAF Waddington. David Oliver reports for Aviation News on the new type in European skies.

Below: Using a radar based on the ASARS-2 carried by the Lockheed U-2, the ASTOR (Airborne Stand-Off Radar) will complement the RAF fleet of E-3D Sentry AWACS and Nimrod R.1s currently operated in the surveillance, command and control, and reconnaissance roles. (Photo, author).

The long-awaited UK Airborne Stand-Off Radar (ASTOR) System moved a step closer on June 6 with the presentation of a new standard to No 5 Army Co-operation (AC) Squadron and the delivery of the first Sentinel R. Mk 1 aircraft to its home base at RAF Waddington.
The ASTOR programme is being supplied by Raytheon Systems to the UK Ministry of Defence under an £800m contract awarded in December 1999 and as a prime contractor, it is responsible for delivering full capability: hardware, software, infrastructure, training and a comprehensive full life support package.

The ASTOR role is to provide 24-hour, near real-time, all-weather, long-range surveillance and target acquisition of fixed, stationary and moving targets for the British Armed Forces. Its operational purpose is primarily to provide commanders with better information about the disposition on the battlefield. The system comprises two main parts, the air and ground segments, along with a third supporting element.

The air segment will consist of five Sentinel R Mk.1 aircraft, a modified version of the Bombardier Global Express business jet. The modification includes a dual-mode 1-D Active Electronically Scanned Array (AESA) ground surveillance radar in the lower radar canoe, SATCOM in an upper radome, a fin extension, three operator workstations in the main cabin and associated computer, image-processing equipment and datalink systems for air-to-air and air-to-ground communication. The Sentinel is equipped with a comprehensive defence aids system (DAS) that includes missile warning system and radar warning receiver, chaff and flare dispensers, a towed radar decoy and a countermeasures dispensing system.

The two operating modes of the radar are synthetic aperture radar (SAR) that produces photo-like imagery of ground targets from radar returns, and moving target indication (MTI) that detects target movement on the ground and in the air. The ground segment consists of two Operational Level Ground Stations (OLGS) and six Tactical Ground Stations (TGS) operated by a mix of Army and RAF crews supported by Army ground engineers. The support segment includes RAF and Army communications and computer specialists to support both the air and ground segments both at the Main Operating Base and at any Deployed Operating Base.

Sentinel will normally operate at a stand-off range from the target area, flying at 40,000ft plus above the surveillance area. It can also operate in an autonomous, ‘untethered’ mode, without ground station support. In this mode, its crew would exploit the data on the aircraft, or collect and store imagery and GMTI data on-board for subsequent exploitation. Once the radar information has been processed, it can be passed by datalink to other ISTAR airborne platforms such as the JSTARS or AWACS aircraft or pass the information directly to US Forces JSTARS Common Ground Stations.

Below: Capable of wide-area image-gathering, the Sentinels (serialled ZJ690-694) will make full use of the ultra long-range capability of this business jet design which has a range of some 6,687nm (12,408km). No doubt, the type will be deployed to trouble spots where British forces are involved. (Photos, Geoff Lee).

For the rest of this feature please see the August 2007 issue.