I've worked out a bit more on the idea. You get each soldier issued with a gun mounted smart phone (I saw a picture somewhere). Each phone has a bluetooth connected mic on the shoulder or wherever. The phone has a microphone (obviously).
You use the African computer project that connects up computers to form an ad-hoc network so each soldier has a sound recorder and position information can be transmitted between each phone. The best signal gets the priority for each round fired and the multiple points registering sound pinpoint the enemy shots more accurately even in a large fight since the phone also knows which direction the gun was facing. Each gun then has a augmented target placed on the camera image so to lay down covering fire the soldier does not need a direct line of site, being able to see the phone is enough or having it emit a sound/ signal if the target is dead ahead. Covering fire being a lot more effective if it is hitting around the enemy.
If the firefight is undercover then the solider drop some mobiles outside and the network pinpoints location using the phones outside. If multiple targets are detected in one location the the GPS can be used to call in an airstrike and the network provides each soldier with a handy "good guys" augmented reality overlay so that if they get split up they don't get caught in their own crossfire.
The main point of failure would be the second mike as the solider could be facing one way with the gun being carried across the body on patrol, so the secondary mike would be relegated to a lower ranking of accuracy if based on movement of the soldier and the difference in normal sound direction from the phone mic. Also a group of soldiers would be more accurate just relying on their phone/ gun mics.as that's where the compass is. Battery power would be an issue in any system.
Wasn't there a darpa competition for this type of thing ? Who wants to sign up ?