How do heat-seeking missiles work? do they work exactly like in the movies?
In: Technology
I still haven’t seen an explanation of the “heat-seeking” logic of the problem that I really like so here’s my attempt.
Starting with the old IR (infrared) missiles it’s fairly simple. If you take an IR camera and point it at the back of an engine it there will be a very obvious hot spot. (https://youtu.be/2C6ZcqeIvjw). Because the difference in temperature between the engine/its exhaust and the environment is so large its easy to identify that as a targeting point. That is why the earliest missiles could only be fired from directly behind the target where they could see directly into the engine where the largest temperature difference would be. Then versions were made where they could detect the difference using just the exhaust instead of the engine core which greatly expanded the angles they were usable from, but still weren’t effective if the exhaust was out of line of sight.
Flares exploit the simplistic nature of this temperature difference logic by creating a larger temperature difference so the missile tracks them instead. To combat this engineers changed what the IR camera is looking at essentially. With better sensor technology the missiles no longer look at just what is the brightest thing in the field of view, instead they look for airframe heating. As a plane flys it encounters air resistance which is essentially friction between the plane and the air. That friction heats up the plane (this is part of why the fastes aircraft require special materials). The temperature difference between the friction heated aircraft and the rest of the sky is measurable but still fairly small. There can certainly be other things in the missiles field of view that have a larger temperature difference, so the missile has to know what it’s looking for. To solve this these missiles have a form of image recognition built into their computers so that they can recognize aircraft shaped temperature differences and target those specifically. That makes it much harder for flares to fool these missiles while also allowing the guidance computers do a better job figuring out where the target is going so the missile can get there first.
Others have covered this in other ways but “Do they work exactly like in the movies?” No. If a missile goes past a target will it turn around to try again? No, at that point it has been defeated. Will a missile chase for over a minute while right behind a plane very slowly getting closer? No, most missiles travel far faster than the aircraft they’re targeting and aren’t going to slow down to give you time to think. Can you out maneuver a missile? Yes… But it’s very very rare and will usually leave you in a very vulnerable position to the next missile. There are methods to reliably defeat missiles, but that isn’t one usually.
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