Veterans of Iraq and Afghanistan may be familiar with the Boomerang system. While I won't get into the technical specifications of the Boomerang system, or other acoustic based technologies I think students of warfare would be well served to look into the field. A quick rundown is available here: http://www.gizmag.com/go/4497/ and another quick read here: http://homemadedefense.blogspot.com/2010/06/military-technology-gunshot-detectors.html
An "emerging" technology, or at least emerging to me, is the mid wave infrared muzzle flash detection systems. The SWAD system out of Israel seems to be mature enough for deployment right now from what I can gather. http://www.elisra.com/SWAD.html
So what does this mean for the future of warfighting? Well it means that snipers will have a harder time working to keep up with technology in the years to come. The ballistic sniper identification technology seems to be less precise than the IR flash detection system, but it is also available and deployed now. It also means that it is possible to spoof either system, for any student of warfare knows that as soon as we develop something to detect an enemy (such as RADAR) it isn't very long before we work out how to deceive that very system (chaff, decoys, stealth technologies, active jammers, etc).
I really would like to get my hands on a SWAD to play with and see if I could defeat it using commercial off the shelf technology, such as jamming the IR sensors with a handheld laser pulled from a Compact Disc burning drive (CDRW drives burned in the IR spectrum). I don't know for sure, but that is where I would start. Other options include shooting through a mist of water to absorb some of the IR muzzle flash, or a tactic change such as using road flares or dazzlers to confuse the system (which I don't think would work). Possibly an IR LED attached to the muzzle of the snipers rifle turned on a few seconds before the shot is taken would cause the computer to dismiss the actual muzzle flash as "background noise" (I have no idea).
Maybe in thirty years we will have Suited Heavy Infantry Troopers with acoustic and IR detection systems that display the real time position of active enemy threats on a shared common operating picture with their squadmates. And maybe there will be a guy like me figuring out how to pain false targets, disrupt the data link between S.H.I.T. members so that an underdog can fight. While they react to a supposed sniper threat they walk into a prepared kill zone or something.
In the old spiritual song, "Down by the Riverside" there is a part that goes "and I ain't gonna study war no more!" which isn't something I recommend anytime soon. Thinking you have mastered your craft is a quick way to be written down in the history books as a fool.