Rise of the all-weather UAV

Armada International, April-May, 2004 by Doug Richardson

Today's armies need to be able to fight in day and nighttimes and in all weather patterns. So tomorrow's Unmanned Air Vehicles (UAV) will need the sane capabilities. A growing number of designs now offer the ability to gather radar imagery of near-photographic quality under all weather conditions.

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In February 2004, Australia announced that it will spend one billion of its dollars (US$ 770 million) to procure a squadron of drones (as UAVs were originally known in the United States) to handle the maritime patrol task and to fulfil land surveillance and intelligence gathering roles. The requirement is for a high-altitude, long-endurance aircraft able to enter service between 2009 and 2011, and although the contractor and sensor payload have yet to be chosen, it is likely that the winning design will be fitted with a Synthetic Aperture Radar (Sar).

One likely candidate for the order must be the Northrop Grumman RQ-4 Global Hawk. In his announcement of the proposed procurement--part of Australia's Defence Capability Plan 2004-2014--Australian Defence Minister Robert Hill highlighted the success that the Global Hawk has had during American operations in Iraq and Afghanistan.

Afghan 'SarLines'

The Global Hawk has already demonstrated its usefulness to the Australian armed forces. In the summer of 2001 a Global Hawk flew eleven demonstration missions over Australia and the surrounding seas, allowing that nation to evaluate its ability to meet a Royal Australian Air Force strategic surveillance requirement.

The aircraft's definitive sensor suite is currently a Raytheon (originally Hughes) package known as the Integrated Sensor Suite (ISS). This teams electro-optical and infrared sensors with a Sar whose gimballed antenna scans from either side of the vehicle. A plan to replace the current Sar by a new variant of the Raytheon Asars-2 carried by the Lockheed Martin U-2S reconnaissance aircraft has been reported. Around 2009 the Global Hawk is due to receive an active electronically scanned array (Aesa) Sar created under the Multi-Platform Radar Technology Insertion Program (MP-Rtip).

Watchkeeper

As these words were being written in early February 2004, Britain was about to select a consortium to develop and supply UAVs to meet the Watchkeeper requirement. Currently the main British drone project, the Watchkeeper is intended to support land forces. Due to reach an initial operating capability in early 2006, Watchkeeper is expected to have a service life of 30 years.

Following the successful use of unmanned aircraft in Afghanistan, the United Kingdom decided to accelerate the Watchkeeper programme, downselecting two consortia to proceed to the next phase of the project, and setting up a new joint service trials unit to begin testing prototypes of the system.

BAE Systems, Lockheed Martin, Northrop Grumman and Thales all took part in the first stage of the Assessment Phase. Northrop Grumman Integrated Systems and Thales (UK) were selected to continue through to the System Integration Assurance Phase, which was intended to prove the integrated capability of the proposed system and to provide the customer with a high degree of confidence that the chosen design could be delivered on time and within budget.

Thales has teamed with Elbit Systems (air vehicles clement), LogicaCMG (digital battlespace integration), Cubic (datalinks), Vega (training) and Marshall SV (vehicles and shelters). Tamam, Thales Optronics/Elop and L3 Wescam competed for the task of providing the electro-optic sensor package. Other team members are QinetiQ, Supacat, Praxis and a number of Thales UK companies.

Two designs are being offered by the Thales-led consortium, these are based on Elbit's Hermes 180 and 450:

* the WK180 air vehicle offers field reconfigurable payload and launch options, allowing a choice of ramp/parachute & airbags, ramp/short strip or strip/strip launch and recovery; it is designed to be air-transportable as a single C-130 load, and able to be operational within an hour of arriving at its operational area: the normal payload is likely to combine an electro-optical suite with a laser marker.

* the larger WK450 air vehicle has almost twice the endurance of the WK180, but carries multiple payloads including a latest state-of-the-art Sar/GMTI radar: capable of fully autonomous ramp or runway launch, it shares many common subsystems and avionics with the WK180, and will be C130 deployable.

Vertical Potential

Northrop Grumman Integrated Systems evaluated the ability of several unmanned systems to meet the Watchkeeper requirements, including its vertical takeoff and landing RQ-8A Fire Scout. At the 2003 Paris Air Show, the company announced that it had completed the integration and end-to-end air vehicle/payload testing of a General Atomics AN/APY-8 tactical synthetic aperture radar on the Fire Scout. (The AN/APY-8 was originally developed for use on the General Atomics Predator, and is described later in this article.)

The Fire Scout had been fitted with the AN/APY-8 gimballed antenna assembly and radar electronics assembly, an independent Global Positioning System and a Northrop Grumman-designed and -qualified Sar/MTI interface unit intended to allow control of the radar via the UAV's existing tactical command data link.