Fuselage Length (WK180)
Take-Off Weight (WK180)
Take-Off Weight (WK450)
More than 10 hours
20 or 30 hours
Loiter Speed (WK180)
Loiter Speed (WK450)
Maximum Speed (WK180)
Maximum Speed (WK450)
UEL AR 741 Engine (WK180)
UEL AR 801 Engine (WK450)
The Watchkeeper is a dual sensor and all-weather unmanned aircraft system (UAS) that provides real time aerial reconnaissance to enable increased situational awareness for ground-based forces.
It was developed by Thales UK in partnership with Elbit Systems, a defence electronics company based in Israel. The Watchkeeper UAV provides intelligence, surveillance, target acquisition and reconnaissance (ISTAR) capability to the UK armed forces.
Watchkeeper UAV system development
In July 2004, the UK Ministry of Defence (MoD) announced that Thales UK was selected as the preferred bidder for the Watchkeeper tactical unmanned air vehicle (TUAV) system.
In August 2005, Thales UK was awarded the contract of £775m ($1.18bn) for the development, manufacturing, and initial support (DMIS) phases of the Watchkeeper programme. 54 Watchkeeper UAV systems were ordered for delivery to the British Army. Watchkeeper is a tactical system that is operated in theatre by the British Army Royal Artillery.
In June 2007, following completion of the critical design review, Thales unveiled the final design which features the dual payload, all-weather operation with de-icing and automatic take-off and landing capability.
First flight of the Watchkeeper UAV was performed in April 2008, from Megido Airfield in northern Israel. Trials of Elbit’s Magic X-band automatic take-off and landing system were successfully completed in August 2008, while trials with the I-Master radar and electro-optic payloads were conducted in late 2008. In April 2010, the UK MoD signed an initial three-year support contract with Thales UK for the Watchkeeper UAS Programme.
In March 2014, the Watchkeeper UAV was deployed for its first operational flights in Afghanistan in support of the British Army’s operations in the area.
The Watchkeeper programme
Four industrial teams led by BAE Systems, Lockheed Martin, Northrop Grumman and Thales UK were considered for the Watchkeeper programme. In February 2002, the UK MoD invited Northrop Grumman and Thales UK to submit bids with emphasis for the bids to outline capability rather than specified platforms. The bids by both teams were submitted to the MoD by March 2004 and Thales UK was announced as the preferred bidder in July 2004.
The industrial Watchkeeper team led by Thales UK includes Boeing; Cobham, Wimborne (major sub-assemblies and components); Cubic Corporation, Greenford (datalinks); Elbit (air vehicles); LogicaCMG, Leatherhead (digital battlespace integration); Marshall SV, Cambridge (ground station shelters and vehicles); Praxis, Bath (programme safety); QinetiQ (airworthiness consultancy and image data management); UAV Engines Ltd, Lichfield (UAV engine); and Vega (training).
A joint venture company, UAV Tactical Systems Ltd (U-TacS), based in Leicester, has been set up by Thales UK and Elbit to produce the Watchkeeper system in the UK. The air vehicle development and manufacturing joint venture is based on Elbit’s capability in unmanned air vehicles and Thales UK’s capability in detection, identification, electro-optics, imaging and signal processing and system integration.
Boeing was selected as a team member to support UK and US interoperability and to play a role in technology and upgrades during the life of the Watchkeeper programme. Watchkeeper is capable of being deployed with partners in NATO, Europe and USA.
Watchkeeper is capable of full integration with both the US network-centric warfare (US NCW) and the UK network-enabled capability (UK NEC). The use of NATO standard data links and international standards for image data transfer contribute to system interoperability.
Watchkeeper WK450 unmanned air vehicle The Watchkeeper air vehicle, designated WK450, is based on the Elbit 450 Hermes tactical UAV.
It allows the user to see enemy activities, if any, at a range of 200km and protect the troops on the ground.
By August 2020, the UAV has clocked more than 3,000 flight hours since its first flight in 2010.
WK450 has a maximum payload capacity of 150kg. The payload includes day / night sensors, a laser designator and a synthetic aperture radar / ground moving target indicator (SAR/GMTI).
In December 2005, the CoMPASS (compact multi-purpose advanced stabilised system) electro-optic observation system, supplied by El-op (a subsidiary of Elbit), and the I-Master SAR/GMTI
radar, supplied by Thales Aerospace in Crawley were chosen as the mission payloads for Watchkeeper.
CoMPASS sensors can include third generation, 3-5-micron focal plane array FLIR, 8-12 micron FLIR, colour TV camera with zoom, eyesafe laser rangefinder, diode-pumped laser designator, laser target illuminator and auto-tracker.
A wide-band satellite link can be installed on the air vehicle. The on-board satellite link can be used to give extended range operation without deploying a separate radio relay aircraft.
Rockwell Collins (Athena Technologies) is the supplier of the Athena 411 navigation system which is an integrated inertial navigation / global positioning / air data attitude heading reference system (INS/GPS/AHRS). Athena 411 weighs only 1kg.
Ground control station
The Watchkeeper UAV is connected by satellite datalink to a network of containerised ground control stations, where the imagery is analysed and disseminated. The 20ft-long ground control station (GCS) supplied by Marshall SV is carried by standard DROPS trucks supplied as government-furnished equipment.
The UAV Ground Control Station is connected with ground elements that feed the relative and absolute location co-ordinates of the UAV to the GCS. The UAVs are connected to GCS via satellite datalinks.
The satellite datalinks then assist the UAV based on the co-ordinates received for safe take-off and landing. This helps for automated take off and landing of the UAV in normal as well as adverse conditions like lower visibility and GPS cut-off.
The UAV is equipped with an inertial navigation system (INS) & Global Positioning System and Pitot systems. In the event of failure of GPS, the system is controlled by means of the datalink. In the event of complete dead reckoning, good position can be located using the INS.
Watchkeeper propulsion system
The Watchkeeper is equipped with a rotary Wankel water-cooled engine produced by UK-based company UAV Engines. The fuel used is aviation gasoline.
The fuel system features an integral fuel and collector tank for continuous and uninterrupted supply of the fuel during manoeuvring.