Just one question, how is the design of a seeker for an Air-to-Air missile different from the design of a Air-to-Ground missile?
The differences were huge, but will actually disappear in the future.
Do you know what a PIR is?
Where you work there is probably one in the room.. it is basically an IR sensor that detects heat and movement and would be part of the security system in most offices.
Old AAM seekers were much like that, they didn't form an image like a thermal imager... they just detected hot spots as blobs, which was used to steer the missile towards a target in the air.
things like the sun or heated rocks on the ground could easily distract such a simple seeker so to get a lock you slaved the missile seeker directly forward and then flew your plane to behind the enemy aircraft where you were looking directly up his engine tail pipe and then locked your missile and fired it.
With no sun behind the target you assumed the target it locked was the target aircrafts engine.
Problem is that a flare is also hot so if he popped a flare your missile might go after that instead.
Later seekers could see more clearly and your average enemy aircraft became a cluster of hot points so an individual flare did not work so well as it was too hot and the missile seeker might have locked onto a less hot part of the target pattern.
Solution was to release an enormous number of flares to create a pattern to distract the seeker.
Point is that these seekers look for IR patterns rather than actual targets so a group of rocks on the ground could look like a vehicle or vice versa.
To engage targets on the ground you need to have an IR image where targets are actually defined shapes as well as patterns.
New AAMs like ASRAAM and Morfei will have IIR or imaging infra red seekers that actually form an image of the target.
Anyway very simply an AAM with an IR seeker has a very simple IR detector sensor, whereas to hit ground targets you need an imaging IR sensor... the latter is also beginning to be used in AAMs as well.
Note the Pantsir-S combines EO (ie Low light level TV, and Thermal Imaging) as well as MMW and CMW radar to track the target and the outgoing missiles... and cheap simple command guidance to send course corrections to the very cheap missile... makes it capable and cheap to use... and indeed able to be used against almost any target within line of sight... including ground targets.