Guarded response

The first Sentinel R Mk I aircraft to have been completed in the UK has left Raytheon's Broughton facility in north Wales for Greenville, Texas, where it will join the US-built aircraft to undertake formal flight testing.

The Sentinel R Mk I, based on a Bombardier Global Express business jet, forms part of the Ministry of Defence's Airborne Stand-Off Radar (ASTOR) long-range surveillance system. The first ASTOR aircraft was modified and integrated in the US while the remaining four Sentinels are being modified by Raytheon Systems, the prime contractor, in the UK.

Raytheon said that when it enters service the MoD's ASTOR system will be the most advanced of its type worldwide. Each aircraft will be equipped with dual-mode (synthetic aperture radar and moving target indicator) radar and workstations where the mission management and imagery can be exploited then transmitted to the various brigades and divisional/joint-level ASTOR ground stations by datalink.

The active-array ASTOR radar is capable of generating SAR imagery of various resolutions, along with advanced moving target indicator modes. The radar data can be simultaneously displayed on ASTOR workstations on the aircraft and on the tactical ground stations. The system will be interoperable with allies' systems and NATO.

When required the airborne segment can operate independently of the ground stations, however, disseminating data to other military systems on the ground or at sea via its communications systems. ASTOR operates in near real time to give commanders rapid access to highly accurate battlefield information.

By operating at altitudes consistent with the 51,000ft ceiling of the unmodified Global Express aircraft and at considerable stand-off distances, the radar platform can remain over safe territory while providing an excellent 'look-down' angle of the area of interest.

The Sentinel will return to the UK in late spring to undertake further flight trials.