Lightweight IRST

Do light and cheap close range IRSTs exist? Say around 8km range. Could they be light enough to be integrated to MANPAD systems?

Or could MANPADs be equipped with a gimballed seeker to search for a target in a significant search volume?I take it that could increase the lethality of MANPADs a lot. The probability of intercepting a incoming plane would be near 100% if the operator is warned that enemy planes are coming from a given angle.

Also, given the fact that armored vehicles are all datalinked now, they could receive data from the air defense network via a Gateway about an incoming raid. Their turret could be used to maneuver and launch a MANPAD with this advanced seeker. If most armored vehicles had a secondary anti-air capability with such a missile, that could be extremely effective against CAS planes, helicopter or even fast planes crossing the front line.