Thales and Israeli firm Elop will provide the dual mission payloads for the UK’s Watchkeeper WK450 unmanned air vehicles in a selection confirmed on 7 December. The companies will, respectively, supply their I-Master synthetic-aperture radar/ground moving target indication (SAR/GMTI) sensor and Compass IV electro-optical/infrared (EO/IR) systems to equip the 450kg (990lb) UAV.

Unveiled at the Farnborough air show in 2004, the I-Master sensor will provide sub-metric resolution SAR imagery from a range of 20km (11nm) in strip mode and 15km in spot mode, and be capable of detecting slow-moving vehicles or people from a range of 20km in GMTI mode, says Thales.

With an expected weight of about 32kg, the I-Master sensor has its roots in the Pod SAR technology demonstration run by the then-Racal from the mid-1990s and draws on technology from Thales’s Searchwater radar family.

Larger SAR/GMTI payloads, including General Atomics’ Lynx system now in use with the Predator UAV, had been considered for integration with the WK450 air vehicle, but these would have restricted it to carrying a single payload. The UK Ministry of Defence favours using its future Watchkeeper air vehicles equipped with both SAR/GMTI and EO/IR sensors, accepting a slight reduction in detection range for the operational flexibility the dual payloads will provide in positively identifying targets.

As well as its reduced weight, “I-Master has the GMTI capability the others don’t have”, says Thales Radars senior marketing manager Alan Gordon. “It will detect movement and cue the EO/IR payload.” Thales claims previous demonstrations of its SAR/GMTI technology have produced “almost identification-quality imagery”, but says its lightweight I-Master sensor has yet to be assembled and will require further flight testing.

The Compass IV had been considered favourite to equip the WK450, having been demonstrated at ParcAberporth this year on an Elbit Systems Hermes 450 – the baseline platform for the UK’s Watchkeeper tactical UAV system. The 40kg Elop sensor can also be equipped with a laser rangefinder and target designator.

Payload production will be funded from a £320 million ($550 million) contract recently placed with Thales/Elbit joint venture UAV Tactical Systems (Flight International, 8-14 November).

To enter service in 2010, the baseline Watchkeeper system is expected to evolve to incorporate other airframes and equipment, potentially including communications relay, satellite communications and hyper-spectral imaging electronic support measures payloads.

Source: Flight International