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Watchkeeper Tactical UAV

In July 2004, the UK Ministry of Defence (MoD) announced that Thales UK had been selected as the preferred bidder for th

Wingspan (WK180)


Wingspan (WK450)


Length (WK180)


Length (WK450)



Watchkeeper UAV

The Watchkeeper UAV provides the UK armed forces with intelligence, surveillance, target acquisition and reconnaissance (ISTAR) capability. In July 2004, the UK Ministry of Defence (MoD) announced that Thales UK had been selected as the preferred bidder for the Watchkeeper tactical unmanned air vehicle (TUAV) system.

In August 2005, Thales UK was awarded the contract for the development, manufacture and initial support (DMIS) phases of the Watchkeeper programme. 54 Watchkeeper UAV systems were ordered for delviery to the British Army. Watchkeeper is a tactical system that will be operated in theatre by the British Army Royal Artillery.

Watchkeeper UAV system development

Thales UK’s Watchkeeper proposal included a large UAV and a smaller UAV, support equipment and ground stations. The MoD has decided that a single UAV solution is more cost effective and only the larger WK450 UAV will be developed.

The air vehicle is capable of carrying a range of sensors including day and night cameras and surveillance radars.

Two WK450 air vehicles are able to operate in tandem, with the second acting as a communications relay. The ground control station is network enabled to ensure comprehensive communications links, for example to airborne stand-off radar, attack aircraft and battlegroup headquarters.

“Watchkeeper provides the UK armed forces with intelligence, surveillance, target acquisition and reconnaissance (ISTAR) capability.”

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.

Watchkeeper UAV first flight and deployment

First flight of the Watchkeeper UAV was 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. Trials with the I-Master radar and electro-optic payloads were conducted in late 2008.

Major flight trials of the Watchkeeper were completed in June 2009, allowing for further ground system and flight tests in the UK. These flight tests moved to Parc Aberporth in West Wales in late 2009. The Watchkeeper made its first UK flight on 14 April 2010. It entered service in the UK armed forces Royal Artillery in 2011. A full Watchkeeper system can be deployed to theatre in a single C-130 Hercules transport aircraft.

As an urgent operational requirement to provide intelligence, surveillance, target acquisition and reconnaissance (ISTAR) until Watchkeeper entered service, the British Army ordered a Hermes 450 UAV (on which the Watchkeeper is based) unit from Thales UK / Elbit. The unit has been operational in Iraq since June 2007 and had completed more than 30,000 flight hours by April 2010.

The MoD extended the Hermes 450 UAV contract, providing ISTAR support to the UK armed forces in operations to run until 2011, when the Watchkeeper UAV replaced the Hermes 450.

In April 2010, the UK MoD signed an initial three-year support contract with Thales UK for the Watchkeeper UAS Programme.

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 will be 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.

“Watchkeeper tactical UAV will be capable of carrying a range of sensors including day and night cameras and surveillance radars.”

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.

WK450 unmanned air vehicle

The Watchkeeper air vehicle, designated WK450, is based on the Elbit 450 Hermes tactical UAV. The Hermes 450 is a proven system with 20,000 flying hours in service. In 2003, the Elbit Hermes 450 system was accepted by the US Naval Air Station Fallon Joint UAV Test and Evaluation Centre in Nevada for joint interoperability trials.

The air vehicle can be pre-programmed to carry out fully autonomous missions and can be redirected in flight by the operator on the ground. Take-off and landing can be piloted or automatic using Elbit’s Magic X-band automatic take-off and landing system. The air vehicle is equipped with global positioning systems, dual computers and dual datalinks. The electrical and avionics systems have built in redundancy for increased reliability.

The air vehicle is powered by rotary engines from UAV Engines Ltd (UEL), based in Lichfield, UK, and uses a two-bladed pusher propeller.

For long endurance missions the air vehicle can be fitted with two 50l underwing auxiliary fuel tanks. The air vehicle has a typical endurance of 17 hours.

Watchkeeper payload

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 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 (compact multi-purpose advanced stabilised system) 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 autotracker.

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.

“Watchkeeper is operated by the British Army Royal Artillery.”

Rockwell Collins (Athena Technologies) supplies 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 GCS, supplied by Marshall SV, will be carried by standard DROPS trucks supplied as Government-furnished equipment.

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