İs there any counter measure sytem to engage at the terminal phase of the IIR imissiles other than maneoveur of the plane?
Advanced detectors come with advanced image processors on those missiles. Modern heat-seeking missiles use imaging infrared(IIR), which is able to produce an image in infra-red, much like the CCD in a digital camera. This requires much more signal processing to be much more accurate and harder to fool. Advanced detectors tracking the targets in different wavelengths along with advanced image processors make them incredible deadly and so, old tricks to fool seeker with
Sun became unlikely because image processors identify the
target shape, even capability of locking onto the section which spreads lower level thermal signals than exhaust. Auto dimmer is also used by those processors.
Resistance to Flares (Main tool to defeat IIR seeker), Early seekers used a single detector that was sensitive to very hot portions of the aircraft like jet exhaust, making them suitable for tail-chase scenarios but This caused them to be fooled by flares easily. New seekers have a dual-frequency seeker which is able to distinguish flares from the actual target.
Other solution to overcome flares are digital processing. In this method, The target data taken by seeker detectors processed to produce an image, something like desktop scanner. Image Processors remember the location of the target from scan to scan, objects moving at high speeds relative to the target could be eliminated. That is called as
cinematic filtering !
The older generation IR missiles would simply point towards the target with narrow looking seekers and chase it not to make them exit out of FOV but this was inefficient in many aspect and absorbing the acceleration energy and thrust power of missiles while seeker itself will be fooled while following exhaust heat.
Newer IIR missiles are smarter and use the gimbaled seeker head combined with
"proportional guidance" in order to avoid oscillation and to fly an efficient intercept path. Proportional guidance is a method widely used by captains/officers working in merchant ships to avoid collision with another ship navigating in a collision route. It is based on the fact that two vehicles are on a collision course, when their direct line of sight does not change direction but the range closes steadily.
How it works in missiles ? Gimbal seeker turns towards target to lock on, while Missile is proceeding a steady course different than the direction of seeker. A gyroscope inside of seeker continuously calculate the relative bearing thanks to data taken by gimballed seeker, while the distance between them are decreasing. If the constant bearing chances a bit thanks to escape maneuvering of target, Gimballed seeker will follow the move, while the processor in missile will immediately draw a new route to make bearing angle the constant again until missile and target collide.
