Moppy said:
Today there are pre-shot sniper detection systems that detect optics by reflection, but they aren't purely passive. They all have to emit something to detect the reflection. Because of this it's the sort of thing that's more useful for a base than an infantry squad.
Huh. I was aware of the post-fire detection systems, but until you mentioned this I hadn't been aware of the newer tech being deployed. I did some digging and see that laser detection systems are out there to help identify optics and such that may be associated with snipers. Some claim to even be able to detect behind windows.
Below is one example of the description of the capabilities of the system. However when I was doing my digging I found LOTS of gobbledygook describing the potential systems, and LOTS of flowery words with semi-technical jargon. For the most part they all seem to say the same thing - and all seem to have large gaps of possible failures to detect. I'm betting that the casual sniper would probably be picked up. However if the snipers are using mil-spec equipment with some military training then these detection systems are probably relatively easy to defeat. Which makes sense, as nearly all military advantages are quickly offset by an (potential) enemy.
Detection range of the optical device like sniper scope up to 1500 m
Automatic scan mode
Providing fully automatic mode of search and detection camouflaged snipers and optical surveillance
Detection optical reconnaissance and aiming with anti-reflective coating on the surface of unauthorized optical elements
New algorithms of detection glare optics on a background of active and passive obstacles.
New methods of detection optics in the conditions of use anti-reflective coating
Weight of the system up to 5 kg
Wired or wireless communication link with external devices