Raytheon UK and the UK Ministry of Defence (MOD) may have taken another step toward retaining in service the Sentinel R.1 aircraft equipped with a dual-mode reconnaissance radar. They are believed to have just signed a contract for the Integrated Radar Programme (IRP), a redesign that merges the receiver/exciter and the processor. The IRP offers a big saving in size, weight and power.

Raytheon proposed the IRP to the MOD as the first phase of a Sentinel Sustainment Plan (SSP) that is aimed primarily at mitigating the problem of diminishing vendors. The Sentinel’s radar was designed in 2000-01 and entered service with the aircraft in 2007. It remains almost unique in providing equally high performance in both synthetic aperture radar (SAR) and moving target indicator (MTI) modes.

The MOD has already granted two reprieves, and its official position is that the five-aircraft fleet should be withdrawn in 2021 as a cost-saving. But Raytheon believes that the aircraft—a conversion of the Global Express business jet—could cost-effectively serve the UK for many more years, and has proposed further upgrades.

Under a separate Integrated Support Services (ISS) contract signed in 2016 and worth £131 million ($170 million), Raytheon is providing engineering, maintenance and training for the Sentinel fleet. This includes C-checks that the airframes require every 10 years. That work is being performed by Raytheon Airborne Solutions in its hangars at Broughton airfield in North Wales.  

Since March 2015, one or more Sentinels have been deployed to RAF Akrotiri, Cyprus, for Operation Shader, the British contribution to the U.S.-led coalition of nations aiming to evict the so-called Islamic State from Iraq and Syria. The aircraft have been flying eight- to 10-hour missions, with its three onboard radar operators using satcom to relay urgent intelligence on the ground situation to UK and coalition commanders. More sophisticated image analysis from the aircraft’s radar has been performed on the ground at Akrotiri, using the portable Intelligence Data Analysis Suite (IDAS) hardware and software provided by Raytheon.

Raytheon is marketing to other countries a version of the Sentinel named the Multi Mission Aircraft (MMA) on which additional sensors and communications options are being offered. These include a long-range electro-optical camera such as the UTAS DB-110; an EO/IR video turret; Sigint systems; and upgraded satcom. The radar could also be improved in ways that are additional to the IRP, such as software enhancements. One of these has already been demonstrated in part. It adds maritime surveillance capability to what has been hitherto almost exclusively a ground-surveillance system. The additional features on the MMA have also been offered to the UK for the Sentinel fleet.