I hear in the news these days about Israelis shooting buildings in Palestinian areas "suspected of harboring snipers" or some such. This gave me an idea:

On the roofs and sides of buildings in a danger zone, place an array of microphones. By using a computer to triangulate the time of the gunshot reaching each micropone, it should be possible to fairly accurately pinpoint the location of anybody using a firearm. Then, of course, measures could be taken to stop the snipers.

If the sniper was using a silencer, however, the task would become more difficult. In that case, the computer system would be able to track the shockwave from the bullet's passage through the air, and extrapolate the line to a likely gun position.

If all this could be done in real time, I envision a great deterrent to such random acts of violence. The invention would have little use other than to protect urban areas, though.
-- badoingdoing, Nov 07 2000

Baked since 1996 http://www.ncjrs.or...les1/nij/179274.txt
A report describing trial runs of ShotSpotter(tm) (Trilon Technology) and SECURES (Alliant Techsystems), both of which are as badoingdoing describes. [wiml, Nov 07 2000, last modified Oct 21 2004]

(?) Surefire Supressors http://www.surefire...rfnbr/517/sesent/00
OK for supersonic ammo, good accuracy, minimal zero shift..... [Custardguts, Sep 10 2006]

I'd imagine that in urban areas you'd hear a lot of echoes of the rifle shot, which could make pinpointing its location very difficult. If several microphones were used and they only worked with the first shot sound, then it might work - automatically controlling a mortar for example to drop a shell on the sniper.
I doubt if snipers use silencers outside James Bond films - they affect the range and accuracy of the weapon.

If you're driving round Jerusalem and your car backfires though - run for it!
-- hippo, Nov 07 2000


Semibaked - The British Army used a similar system on many of the armoured cars in Northern Ireland. When hit with a bullet, a panel lit up to indicate which side had been hit from which direction. I dont know if this is still in use.
-- ickledinkle, Jan 11 2001


Playing the devil's advocate here- wouldn't this defeat the purpose of snipers?
-- salmon, Jan 18 2001


I had heard of a similar systme in the works for rapid police response - identification and triangulation of gunshots and immediate dispatch of police to the area.
-- djymm, Apr 02 2001


Gunshot sound triangulation plays a major role in most Kennedy assassination theories, as well.
-- egnor, Apr 02 2001


Snipers cannot use "silencers" since most firearms they use send the bullet at speeds 3 to 5 times higher than sound. The supersonic "crack" is heard right out from the muzzle. Silencers are good for .22 .32 and .45 caliber pistol ammunition since the bullet travel at slower speed than sound.

Snipers use high power rifles, not pistols. We see a lot of silencers on rifles... on movie screens.
-- macguru, Aug 13 2001


The RPG Cyberpunk had this as an addon for cyber-ears. It communicated between different people with the same thing, triangulating from them and marking your field of sight with the course of the bullet.
-- StarChaser, Aug 13 2001


This could work, and would lead to an interesting and ever more sophisticated attacker-vs-defender arms race. Once a gunfire-pinpointing system using microphones mounted on soldiers and vehicles is made to work the sniper will widely scatter rifle-like firecrackers to confuse his target's sensors. The defender will then add radar: tracking bullets back to their source while they're in flight (I think similar systems already exist for locating heavy artillery). At this point the discerning sniper will start using stealth bullets made from materials less visible to radar. This will cause the defender to be even cleverer with even wizzier sensors, at which point the sniper responds with the next generation of cloaking device. And so on.
-- Skinny Rob, Aug 14 2001


Alternatively, the sniper could place remotely-operated, single-shot, minimally-steerable throwaway rifles at various points, and then fire the appropriate one at the appropriate time through a (encrypted) radio link. Obviously this would work better for assassinations than for (say) urban warfare.
-- wiml, Aug 16 2001


Apparently placing waving flags or shiny stuff in the vicinity of the about to be shot person/thing's area is really distracting to snipers

It's cheaper too!!!
-- torch0, Sep 08 2006


Wish I could bone annotations.

They're called supressors. Modern supressors CAN be used with supersonic ammunition. They do not slow down the bullet, or any such thing, in fact in many cases, the muzzle velocity will be somewhat higher. They are used to reduce muzzle blast. And some work, very very well. Yes, the "crack" can be heard, but a supersonic crack is very difficult to trace back to the source, for a variety of reasons.

I have no idea how to link, will try in a minute, but on surefire's website (surefire.com) is an article on how one brand of supressor works.

Lastly, [macguru], "speeds 3 to 5 times higher than sound". First, you're terminology is wrong. by saying "higher than sound" you're suggesting in ADDITION to sound ie 4 to 6 times that of sound. but anyway, please let me know what rifle callibre you have that can fire a round at 5 times the speed of sound, other than exotic vehicle mounted guns (russian 23mm anti aircraft might come close, but don't think so..). No really, that's 1670 metres per second, or ~5550 fps. wow. no really, wow. tank main guns with fin stabilised sabot rounds only just reach that. I'm prepared to stand corrected, but I certainly haven't heard of any rifle round doing 5550, and I do read a lot.

Doesn't make the idea feasible, but check your facts please. Supressors are in use all over the place, from SWAT teams, to special forces mobs here and there, and yes, they are used on sniper rifles with supersonic ammo too.
-- Custardguts, Sep 10 2006



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