Can gunshots be triangulated with sound analysis?

August 10, 2008 12:16 PM

Pinpointing gunshot locations by triangulating sound waves: Would this be technically feasible? Would it be legal?

Would it be technically possible, with an array of sound monitoring devices placed on utility poles, to determine the source of loud sounds, such as gunshot reports, by relying on very exact time signatures and possibly volume levels? Would this be super-expensive?

Would it be legal for a city or business to deploy such devices?

posted by odinsdream to technology (18 comments total)

Did you even try to use google to find this?

A search for "gunshot sound triangulation" turns up lots of information

Yes, they exist, and yes, they have been deployed.
posted by chrisamiller at 12:20 PM on August 10, 2008 [1 favorite]

I remember seeing a project a few years ago that did EXACTLY this, deploying sensors onto utility poles. Turns out that if you google for 'triangulate gun shots', an article comes up on it on the first page: City goes high-tech to track gunshots from Oakland, CA.
posted by jedrek at 12:20 PM on August 10, 2008

Sorry, I didn't mean to be that obnoxious with the 'just google it' comment. Been a long day.
posted by chrisamiller at 12:21 PM on August 10, 2008 [2 favorites]

The 2007 March issue of WIRED magazine features an article on ShotSpotter.
posted by plokent at 12:38 PM on August 10, 2008

Yeah, the fun thing about gun shots is that they end up in a very specific range, sound-wise, so they're VERY easy to listen for. And because of how acute they are, they're VERY easy to triangulate. Relatively speaking.

As the other posters say, it's been done.
posted by disillusioned at 12:51 PM on August 10, 2008

YES. I had this VERY same idea back in 2001 when we were hearing rifle shots around our 10-acre property. I bought a sound board that had 3 microphone inputs, and my idea was to bring in sound from three microphones 200 feet apart in a triangle -- yielding an easily-measurable 0.1-0.2 second delay. The problem was I didn't have much of an idea on how to program detection of sound in real-time, and didn't know where to turn to, so I shelved the idea.

I'd take a stab that there's 50 patents out on this already, so I have some skepticism about the idea being a goldmine. But best of luck to you anyway since it appears no one has bothered to roll this out to the common man.
posted by crapmatic at 1:04 PM on August 10, 2008

The have this installed in Redwood City, California
posted by bottlebrushtree at 1:05 PM on August 10, 2008

We have it in minneapolis as well.
posted by senseigmg at 1:18 PM on August 10, 2008

We have it in Boston.

They initially had a lot of trouble with it, because it didn't deal well with the smaller, windy-er Boston roads, but evidently they tweaked it and it is working better now.

There was an article on boston.com about it a while back that the OP could google for. I'm too tired.
posted by gregvr at 1:20 PM on August 10, 2008

DC's got it too.
posted by inigo2 at 1:34 PM on August 10, 2008

There was an article on boston.com about it a while back that the OP could google for. I'm too tired.

There was a Boston Globe article just this past week: Gunshot detector finally on target.
posted by ericb at 1:48 PM on August 10, 2008

Wasn't this the plot of a movie with John Travolta as the star? Blow Out?
posted by fixedgear at 1:55 PM on August 10, 2008

I remember seeing a (science) show about a system developed for the US military for use in the field. It was capable of identifying the location of the shooter before the round actually hit the target.
posted by NormandyJack at 3:02 PM on August 10, 2008

Minneapolis has had this for a few years, and it appears to be a commercially available system. They even offer maps!
posted by neckro23 at 3:15 PM on August 10, 2008

Available, off the shelf.

Boomerang is a low cost small arms detection system that provides enemy shooter location in under a second via visual and auditory alerts. The system operates on moving vehicles up to 60 MPH in dense urban enviorments and open terrains. Boomerang is easily integrated with situational awareness systems, and weapons stations.

NOTE: Boomerang is deployed in Iraq and Afghanistan with over 700 systems fielded in fixed and mobile configurations.

posted by Exchequer at 4:29 PM on August 10, 2008

Today in Birmingham, AL
posted by loosemouth at 4:44 PM on August 10, 2008

And Chicago.
posted by gjc at 7:09 PM on August 10, 2008

fixedgear: No triangulation involved.
posted by dhartung at 10:29 PM on August 10, 2008