A laser warning receiver is a type of warning system used as a passive military defence. It detects, analyzes, and locates directions of laser emissions[1] from laser guidance systems and laser rangefinders. Then it alerts the crew and can start various countermeasures, like smoke screen, aerosol screen (e.g. Shtora), active laser self-defence weapon with laser dazzler (LSDW, used on the Chinese Type 99 main battle tank[2]), laser jammer, etc.