Raytheon Sentinel

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Raytheon Sentinel R1
British Air Force Sentinel R1
Type: Reconnaissance plane
Design country:
First flight:

May 26, 2004



Number of pieces:


The Raytheon Sentinel R1 (Sentinel, English: "Guardian") is a reconnaissance aircraft of the British Air Force based on the Bombardier Global Express , which was specially developed and built for battlefield surveillance in Afghanistan . The job of the Sentinel is to track down and track small movable land targets (e.g. tanks ). The first machine was handed over to No.5 Squadron (AC) in Waddington in June 2007 , and all five systems ordered have been operational since the beginning of 2009. In 2017 one machine was taken out of service for budget reasons.

Due to the positive experience in the Afghanistan mission, the British government decided to continue using the aircraft until 2018. In addition to being used for the reconnaissance of enemy troop formations, the machine was also used for situation assessment during humanitarian disasters.



The order for the ASTOR ( airborne stand-off radar ) was awarded to Raytheon Systems Ltd by the British government in December 1999 . Based on Raytheon's ASARS-2 radar system, an airborne battlefield radar has been developed that can be used by both the British Navy and the Army . The first machine to be converted was delivered to Raytheon in February 2002. The first flight of the first Sentinel R1 took place in May 2004. In addition to Raytheon, other suppliers are also involved in the overall system. Bombardier is supplying the basic aircraft, L-3 Communications the ground stations, Lucas the electrical equipment, Messier-Dowty the landing gear, Agusta Westland the doors and Rolls-Royce the engines.


At the end of 2008 the machine was officially put into service two years later and has been in use in Afghanistan since then. The costs of the system, including the ground station, amount to around one billion euros.

With their commissioning, the Sentinel initially took over all tasks of the Nimrod R1 in the role of reconnaissance overland from 2011 ; With the decommissioning of the last Nimrod MRA4 , the British armed forces will not have any capabilities of their own for reconnaissance at sea until an appropriate solution is found .

In the American armed forces, a fleet of 17 Boeing 707s designated as Northrop Grumman E-8 JSTARS is operated for the same task , but they have reached the end of their life; replacement of several Raytheon Sentinels is also being considered.


Operations in conflict and war zones

After the withdrawal of NATO forces from Afghanistan, the machines should already be decommissioned according to the government's new white paper. Triggered by the positive experience with the operation over Libya in 2011 , during the International Security Assistance Force in Afghanistan and the support of the French armed forces in Mali in 2013, David Cameron announced on July 14, 2014 that the R1 mission would be continued until 2018. In addition, the sea should be used - Monitoring capabilities of the system are expanded. From March 2015, the Sentinel will also fly reconnaissance missions over Iraq to investigate the movements of the Islamic State .

Operations to provide support in humanitarian cases

In addition to their actual military tasks, the machines were also used for situation reconnaissance during the 2013-2014 floods in England . In 2014, a machine was also used over Nigeria to search for a group of 200 schoolgirls kidnapped by the Boko Haram terrorist group . The machine flew its missions from Accra in Ghana and thus supported American aircraft.


Initially it was planned to use the machines only for a few years as an interim solution, but the experience was positive and no replacement was available, so that the machines should be in service until further notice; a decommissioning of two machines planned for the end of 2016 has already been postponed to March 2017 at the earliest. One aircraft was mothballed this year and the four remaining aircraft are to follow in the next few years.



The aircraft is a converted Bombardier Global Express that is piloted by two pilots. Externally visible are various radomes and additional stabilization surfaces under the stern. The interior consists of control consoles and is designed for a mission duration of 14 hours. The machine typically flies at an altitude of 15 km and can cover up to 12,000 km. It is powered by two Rolls-Royce BR710 twin-shaft engines with 76 kN thrust each.


The radar is a further development of the ASARS-2 side-view radar, which was also used in the Lockheed U-2 . It delivers high-resolution data from a distance of up to 160 km regardless of the weather and uses a synthetic aperture radar antenna from BAE Systems . The system can automatically identify and track moving targets. The individual scanning strips can be lined up to form an overall situation and thus provide a photo-like image of the combat zone. The data obtained are displayed to the emergency team in the aircraft and can be transmitted to ground stations via various secure connections. It enables real-time evaluation of the data, also by ground troops. An upgrade is planned so that the fleet can also be used for maritime reconnaissance purposes.

Defense measures

The defense equipment of the Sentinel R1 is based essentially on further developments of the devices that were also used in the British Aerospace Nimrod , such as the missile warning system, a towed radar decoy, radar warning receiver, chaff and IR disruptor launchers. The facilities are combined in the DAG (Defensive Aids Group), which comes from BAE and Nashua.

Ground station

The ground stations developed for the Sentinel R1 system allow data to be viewed in real time and can also receive and evaluate data from U-2 and Boeing E-8 Joint STARS aircraft. You are on all-wheel drive Steyr Pinzgauer trucks.


The standard crew consists of five soldiers: in addition to two pilots, a mission commander decides on the exact location, he is supported by two image evaluators. The pilots and mission commanders come from the Royal Air Force, some of the image interpreters from the Signal Corps .

Technical specifications

Parameter Data
crew 5
length 30.30 m
span 28.50 m
height 8.20 m
Wing area 94.90 m²
Empty mass 24,000 kg
Max. Takeoff mass 42,200 kg
Top speed Mach 0.75
Service ceiling 14,935 m
Range 9250 km
Max. Duration of use 9 h
Engines two Rolls-Royce BR710s with 65.60 kN thrust each

Web links

Commons : Raytheon Sentinel  - collection of images, videos and audio files

Individual evidence

  1. ASTOR Sentinel R1 Airborne Stand-off Radar Aircraft. In: airforce-technology.com. Retrieved December 9, 2019 .
  2. FlugRevue February 2009, p. 15, Sentinel R1 in service
  3. ^ JSTARS Replacement: Competition Opened Wide. In: Defense Industry Daily. March 28, 2016, accessed September 24, 2016 .
  4. ^ Caroline Wyatt: On board the RAF's Sentinel R1 spy plane over Libya. In: BBC. May 11, 2011, accessed September 25, 2016 .
  5. a b Retaining Unparalleled Situational Awareness. In: Raytheon. Retrieved September 24, 2016 .
  6. RAF Sentinel Reprieved ... until 2018. In: AIR International August 2014, Breaking News, p. 4
  7. Beth Stevenson: RAF Sentinel may be positioning for anti-Islamic State fight. In: Flightglobal.com. March 12, 2015, accessed on March 12, 2015 (English): "Sources have revealed that the Royal Air Force's Raytheon Sentinel R1 surveillance aircraft is due to be transferred to an undisclosed base in the Mediterranean, suggesting that it is being positioned to join the coalition fight against Islamic State militants. "
  8. UK deploys RAF Sentinel to help search for missing schoolgirls. In: Government UK. May 18, 2014, accessed September 25, 2016 .
  9. ^ RAF Sentinel fleet unaffected until at least March. In: Flightglobal.com. October 28, 2016, accessed October 28, 2016 .
  10. Tim Ripley: RAF Sentinel R1 hunting IS again | Jane's 360. In: Janes.com. April 23, 2018, accessed October 21, 2018 .
  11. ^ Gareth Jennings: UK to upgrade Sentinel R.1s for maritime operations. In: Janes. October 28, 2014, accessed September 25, 2016 .
  12. Sentinel R1. (No longer available online.) In: Royal Air Force. Archived from the original on December 30, 2011 ; accessed on September 24, 2016 (English).