Watchkeeper is a programme, not just a piece of equipment.

Thales and Elbit formed a joint venture called UAV Tactical Systems Ltd to produce and support Watchkeeper.

Systems and suppliers include;

  • Thales; Lightweight, Multiband Airborne Radio (LMAR), a modified PRC6809 Multiband Inter/Intra Team Radio
  • The Thales/Elbit joint venture, El-Op, provide the sensor payloads.
  • Boeing and Cobham; sub-assemblies and components
  • Cubic Corporation; Tactical Common Data Link, also provided through Ultra The system provides up to 11 Mbs over a maximum range of 150km in a package weighing no more than 4.5kg
  • Lola; airframe composites
  • Elbit; air vehicle
  • ABSL; Lithium Ion emergency power backup
  • LogicaCMG; digital battlespace integration
  • Marshall Specialist Vehicle; ground station shelters and vehicles
  • Altran Praxis; Safety engineering
  • Thales; MAGIC automated take-off and landing system
  • QinetiQ; airworthiness consultancy and image data management
  • Elbit/UAV Engines Ltd; UAV engine
  • Vega and Mak Technologies; training
  • Athena Technologies; Inertial navigation system
  • Secure Systems and Technologies; TEMPEST R ruggedised computing and network equipment for the Ground Control System and image analysis.

The additions include;

  • Substantial redesign of the existing air vehicle to provide greater payload, structural integrity and ease of maintenance
  • Enhancement of EO/IR sensor resolution
  • Addition of an SAR/GMTI radar sensor
  • Addition of a Laser designator/rangefinder
  • Redesign of the undercarriage and arrestor wire to allow rough strip operations
  • Landing lights
  • Additional electrostatic discharge and lightning protection
  • Addition of an Automatic Take-Off and Landing (ATOL) system
  • Secure UK datalink and communications infrastructure
  • De-icing system for improved survivability and operating envelope
  • Integral expeditionary and mobile capability
  • Organic training facility
  • UK airworthiness qualification and Release to Service for UK training
  • The UK logistic infrastructure, manufacturing and repair facility

In broad terms, the Watchkeeper programme consists of;

  • Air vehicles, each with an EO/IR/LSS and SAR/GMTI payload
  • System integration
  • Ground equipment
  • Training System

Concept of operations;

Watchkeeper Concept

Air Vehicle and Payload

The Watchkeeper air vehicle is a modified Elbit Hermes 450A, called the Hermes 450B. Total weight is approximately 500kg, it has a maximum range of 115km with an endurance of greater than 16 hours.

Whilst the Hermes 450 and Watchkeeper look the same, they are not the same, far from it. As can be seen from these images, the Watchkeeper air vehicle differs from a standard Hermes 450, on the left, the standard A model, and for Watchkeeper, the B model.

Hermes 450A and B

Differences in the undercarriage, wing root and the twin payloads are particularly noticeable.

Watchkeeper has growth potential to 650kg and a much more robust airframe. Two particular features of importance are rough field landing and wing de-icing. A take-off distance of 1,200m is needed which may limit deployment options.

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The Dual Air vehicle Container is a particularly ingenious container for the disassembled air vehicle, two per container, but I guess you knew I was going to say that!

It has moved on somewhat, from the container shown here

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Watchkeeper Air vehicle Container

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Watchkeeper has two payloads, optical and radar.

The 32Kg 620W Thales I-Master / Viper (Ku-band 12.5 to 18 GHz) synthetic aperture radar / ground moving target indicator (SAR/GMTI).was eventually selected for Watchkeeper. I-Master was developed from the Racal POD SAR and includes technology from the Searchwater radar. It can rotate trough 360 degrees operate up to 20km in strip mode and 15km in spot mode, able to detect slow moving targets such as vehicles or people out to 20km.

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I Master 2

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I Master 1

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There are four GMTI operating modes (sector, 360 degrees, tracking and spotlight) and two for SAR (strip and spotlight). GMTI is extremely useful for change detection, showing patterns of life and tracks, for example, the same kind of capability as delivered by the RAF’s Reaper and Sentinel (and RN Crowsnest) systems. I Master also has a number of new maritime modes.

Working in conjunction with the I-Master is a 38Kg El-op CoMPASS IV (compact multi-purpose advanced stabilised system) electro-optic observation system that also includes a laser range finder and target designator.

From the product page

COMPASS IV can be configured with a variety of sensors to optimize your mission specific objectives. Optional sensors include an eye-safe laser rangefinder, daylight TV, spotter scope, laser area illuminator, laser pointer, and diode pumped laser designator. A step-stare function allows the capture of full-frame digital stills, which are geo-registered at the pixel level and can be tiled for high-resolution area coverage.

Brochure here

Watchkeeper Compass

The Compass is mounted in the front position and the I-Master, the rear.

The dual sensor system is one of the most important features of Watchkeeper.

Maritime and Littoral

Although it was not in the original requirements, Watchkeeper has evolved such that it is being trialled for maritime and littoral operations.

The Royal Navy’s ‘Unmanned Warrior’ exercise

The Thales Watchkeeper unmanned air system is set to play a key role in a major UK Royal Navy exercise later this year to understand how unmanned systems in the air and at sea might add real innovative operational capability in a military maritime environment. More than 50 vehicles, sensors and systems from across defence and industry will be deployed in the Ministry of Defence Unmanned Warrior exercise in October. For the first time, Watchkeeper, currently in service with the British Army, will fly in a littoral naval environment operating alongside a warship and a merchant vessel. As an industry leader in autonomous and unmanned systems, Thales will be showcasing its capability through Watchkeeper, the Halcyon Unmanned Surface Vehicle and its collaborative work in the field of unmanned command and control research. Watchkeeper will be integrated into a series of exercises varying from persistent wide area surveillance support up to 150 kilometres offshore, to landing forces and naval gunfire support. The combination of Watchkeeper’s Electro-optical/infrared sensor and I-Master Radar make Watchkeeper optimised for both land and sea operations, and for tracking fast moving targets such as jet skis and small boats. Data collected by Watchkeeper will be streamed down remotely to the vessels and analysed by trained operators to make better-informed command decisions in support of the trials exercises

This has been enabled by continuous work by Thales on the i-Master SAR, specifically its ‘maritime modes

MMTI allows users to detect and track targets on water: from small, fast-moving craft such as jet-skis; to larger, slower vessels such as ships and tankers, in all weather conditions, day and night. Algorithms designed specifically by Thales allow users to perform a range of tasks that include detecting unusual vessel movements, perform “pattern of life” analysis, and conduct persistent tracking of targeted vessels.

With MMTI mode, I-Master can now see the widest range of man-made movement, from an individual walking on the land to a ship sailing on the sea, and everything in between, using a single sensor.The new maritime mode is designed for customers seeking to monitor maritime borders and exclusive economic zones, protect strategic maritime assets, and track the movement of vessels not using the Marine Automatic Identification System

Cross-cueing of sensors has provided Watchkeeper with a valuable maritime surveillance capability.

Thales imaster maritime

Although Watchkeeper can technically land and take off within the flight deck restrictions of a Queen Elizabeth class aircraft carrier no plans for this have yet been announced.

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Ground Equipment

The Ground Controls Station is the primary mission planning and control location, able to operate connected to a wider network or as a standalone capability. It is full demountable and standard ISO container sized.

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Watchkeeper ground Control Station 1

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Watchkeeper ground Control Station 2

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Each GCS can control three air vehicles.

In order to improve safety and reliability during landing and take-off, an automated system is used, the Thales MAGIC ATO.


The Thales solution utilises an X-Band radar and beacon. In the image above, the large tripod mounted object is the Ground Radar Unit (GRU) and the smaller device, the Ground Beacon Unit (GBU). A smaller beacon is also carried on the aircraft. The other object shown above is the Power Control Unit (PCU). Further information can be found here

Data link and arrestor cable systems complete the ground equipment

Watchkeeper Data Link and Arrestor Cable

The system is transported on standard Army vehicles, a special to role Pinzgauer also used for air vehicle towing and other tasks called the Flight Line Command Support Unit (FLCSU).

Remote video terminals and tactical terminals complete the equipment set.

They are typically laid out as per the diagram below.

Watchkeeper runway layout


Training is provided from a dedicated facility at Larkhill.

Watchkeeper Training

Ascension Island will also provide an alternative training location.

Watchkeeper Ascenion Island 1

Possible Watchkeeper Futures

Thales are leading an export push for Watchkeeper, branding it Watchkeeper X (WKX)

The WKX variant removes UK specific content and allows customers to specify a range of payload and systems components.

“Watchkeeper X is based on a groundbreaking, world leading unmanned aircraft system that was designed specifically for the requirements of the British Army. There is no other capability like it available in today’s market. We have now taken the knowledge and expertise that we have gained over the history of the programme and looked at how we can make it more flexible, effective and readily available for our customers, to help them address the different operational contexts they may face.”

Pierre Eric Pommellet, Thales Executive Vice-President, Defence Mission Systems

Thales are also marketing a shipborne Ground Control Station (GCS) and a number of alternative payloads such as maritime surveillance radar, communications intelligence systems (COMINT), radar electronic support measures (RESM), and cryptographic electronic support measures (CESM).

The two most immediate prospects seemed to be Poland and France.

For the French requirement, Thales have proposed a new 1920 x 1080 camera from L’Heritier (as opposed to the 720 version on Watchkeeper), a French datalink and full compatibility with French C4ISR systems. For Poland, Thales proposed using a number of Polish integrators and arming it with four freefall LMM’s. It was also suggested that Poland would finance the purchase through a UK Government guaranteed loan.

Watchkeeper LMM

Middle East sales may also be a possibility, especially given the relatively ITAR free content of Watchkeeper.

France eventually selected the Sagem Patroller instead of Watchkeeper.

Thales are also planning to integrate the FLIR Systems Star Safire 380-HDc, providing higher resolution imagery than the Compass IV.

For the UK, the short term focus is in bringing the equipment into service and making sure there are sufficient personnel to operate them. Beyond that, SIGINT or other payload improvements might be delivered through a spiral development programme, perhaps even arming them.


Table of Contents


Watchkeeper History

Watchkeeper Description

Summary and a Few Thoughts



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