Defence project set to explore aircraft IR threat detection

The £24.5m project builds on many years of work honing IR systems — conducted by Thales and the Defence Science and Technology (Dstl) Laboratory — which is ultimately aimed at accurate detection in complex environments.

Alan Rae of Thales’ Optronics Division, explained to The Engineer the traditional and existing methods of aircraft threat detection.

‘Countermeasures vary according to the threat,’ he said. ‘Chaff is used to counter radar-guided missiles and flares to counter IR missiles while jamming is only effective against radar guided missiles, and is normally used in conjunction with the deployment of chaff.’

Basic IR threat-detection systems have been used in the past but they have difficulty filtering out background IR clutter originating from the earth, in turn leading to a high rate of false alarms.

Mitigating these false alarms requires vast computing power to intelligently distinguish between genuine threats and interference.

‘Thales has gained, from previous programmes, extensive experience in the processing of IR data and it is this experience that has enabled us to develop the innovative and highly sophisticated algorithms necessary to deal with this issue,’ said Rae.

The technology demonstrator, scheduled for completion in 2015, will use up to six single-colour IR sensors to provide full coverage of the volume and the aircraft and use Thales’ algorithms on a central processor.

According to Rae, it should be effective against a range of threats, including guided missiles; man-portable air-defence systems (MANPADs); surface-to-air missiles (SAMs); IR-, laser- and radar-guided hostile fire; RPG and other unguided missiles; and multi-calibre guns.

Testing at each stage of the development will use a bespoke evaluation and validation. Dstl will conduct a series of ground and flight trials to assess the system’s performance in representative conditions.

‘Initially the system will be fitted to rotary-wing platforms and fixed-wing transport aircraft, however, the system will also be suitable for unmanned aerial vehicle (UAV) applications, as well as the protection of ground vehicles and installations,’ Rae said.

Indeed, the system’s sensors will also be capable of generating IR imagery from all around the aircraft to aid aircrew situational awareness and include data recording to support effective mission planning and post-mission replay.

‘Situational awareness is a critical need for all air platforms, the ability of this system to provide a 360^o view around the platform will be a significant increase in capability. Clearly this will be of great benefit to unmanned systems and the sense-and-avoid requirements,’ Rae said.