Raytheon confirmed at Farnborough it is still confident of achieving the planned autumn 2005 in-service date (ISD) for the RAF's new Sentinel R1 ground surveillance aircraft, based on the Bombardier Global Express.

The Sentinel uses an advanced ground surveillance radar, with a one-dimensional active electronically-scanned antenna in the prominent ventral 'canoe' fairing to detect and track ground targets, using advanced datalinks to send the 'radar picture' to ground stations . The aircraft also has a sophisticated SATCOM system, allowing it to deploy 'off tether'.

The ISD milestone is defined as being when two aircraft, two ground stations and logistics support are in place, and three crews are 'limited combat-ready'. Initial Operational Capability is due in April 2007, when four air crews are fully combat-ready. The type is halfway through its military aircraft release trials, and training is due to begin later this year. 5 Squadron's facilities at RAF Waddington have been completed (seven months ahead of schedule) and a complete set of training equipment was installed in June 2004.

Raytheon joined the ASTOR programme in February 1995, when it won one of two project definition contracts. The company was selected as the preferred contractor in June 1999, and a contract was signed in December 1999.

The five 'green' aircraft have now all been delivered, and the first converted Sentinel flew for the first time in May 2004, though Raytheon had already flown 300 hours in the first Global Express that had been modified to be 'aerodynamically representative' of the Sentinel configuration. Pilots report that the modified aircraft have virtually identical handling characteristics and performance to the 'vanilla' Global Express, and well-publicised weight issues are not believed to impose any significant operating restrictions.


Plans to fit an inflight refuelling probe were abandoned in 2001, but the aircraft is based on the 14.5 hour endurance, 6,700 nm range Global Express, so can meet all range and endurance requirements without refuelling. Integrating a probe on what is a relatively small, clean aircraft produced a relatively large aerodynamic disturbance, and threatened significant programme risk.

The aircraft has huge potential for 'modularity' and could be fitted with other sensors, while its datalinks and ground stations are compatible with other data formats.

The aircraft could therefore be used in the reconnaissance role using a suitable EO-LOROP sensor, or for the 'surrogate' control of UAVs, though there is no formal RAF requirement for such applications.



Source: Flight Daily News