I was wondering are these electrically propelled small UAVs radiate enough heats for IR missiles (like HISAR A) to lock onto?
They generate heat up to 180°C on their magnets as this is usually how much the magnet can take without failing. They will surely pick this up in close distance but how close needs to be tested.
Whether or not they can be locked onto by HİSAR, it's worth considering that a lot of FPV drones are skimming the ground far too low for air defence missiles to hit. Especially the wired variants.
This is a massive dilemma and for now the only option is to have anti-drone air defences nearby.
I think in a few years we'll see counter-drone drones "docked" to a lot of military vehicles including sophisticated mid-long range AA systems. As the software on these improves they'll be highly effective at instantly detecting and destroying incoming drones. We could also see APS-like systems designed for small drones that uses standard small caliber rounds.