The Silent Stealth Sensor

The Strategy Page ^ | 11/20/2009 | The Strategy Page

[ErnstStavroBlofeld]

The U.S. Navy is playing catch-up by equipping some of its F-18E fighters with IRST (Infa-Red Search & Track). The first F-18E Block IIs are entering service, carrying an IRST pod. IRST uses a high resolution infrared (heat sensing) radar to positively spot and identify a potential aerial target (using a 3-D model of the target in its computer memory.) This is similar to the ATFLIR (Advanced Targeting Forward Looking Infrared) pods used to spot surface targets. FLIR (Forward Looking Infrared Radar) has been around since the 1980s, and as the technology became more powerful, it was possible to spot and identify targets at longer ranges. The ATFLIR can identify ground targets from 20 kilometers away, and the latest IRST systems have an even longer range. It eventually became possible to use FLIR, in the form of IRST, as a sensor for spotting aircraft. This was a big advantage, because FLIR is passive. It doesn't broadcast, like normal radar, thus the target cannot detect those radar transmissions, and be alerted that it is being "painted" by a hostile radar.

Russian and European fighters (MiG-29, Su-30, Eurofighter, Rafale) have long had IRST. For the Russians, this was seen as a way to deal with stealthy American aircraft. The U.S. stealth warplanes were built to defeat radar. But these stealthy aircraft still gave off heat, and IRST thrived on seeking out heat.

[JBR34]

IRST is not a radar.

Radars do not sense heat.

It is a passive system. That is the point.

And the acronym FLIR does not mean Foward Looking Infrared Radar.

It means Forward Looking InfraRed.

[GBA]

IRST sensor on the Soviet SU-27UB FLANKER aircraft exhibited at the 38th Paris International Air and Space Show at Le Bourget Airfield. 12 June 1989

[ErnstStavroBlofeld]

Thanks for pointing this out. You learn something new every day.

[Tallguy]

Russian fighter-interceptors have been using FLIR technology years before Stealth technology was publically acknowledged. I think this indicates that the initial reason for passive infrared was to eliminate the need to turn on one’s own search radar & give the ambush away. In any case, Stealth is not only low-radar observability, it also involves the mitigation of the aircraft’s heat signature.