Good research.
It is sometimes very difficult to determine a threats location given certain terrain, weather etc.
OODA loop can be useful.
5.56mm
Okay, everyone hold your fire while the sensors decide where the incoming fire is coming from.....
Too many echoes and obstacles to use plain acoustics, plus the urgent need for return fire.
Bullets are hot. IR emitters. What about a hovering drone with SWIR and a bit of vomputing power algorithm to “see” and differentiate incoming and outgoing promos. Net work a few together to validate and provide the unit a grid or at least a distance and direction....
Regarding sonic shock, our often encountered incoming small arms (762x39) is subsonic from about 400 yards out, but still heated and emitting IR.