Gunshot Sensors


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Regen
May 1, 2008, 01:35 PM
While read an article (http://www.washingtonpost.com/wp-dyn/content/article/2008/05/01/AR2008050101587.html?tid=informbox)in the Washington Post today, I noticed the following quote:
Gunshot sensors indicated that the first shot fired in the confrontation that night did not come from the officers but from a higher-caliber weapon that would have been close to where the youth was found.

I had heard about experiment sensors several years ago that could pin point the location of origin for gunshots, but I did not know that they were deploy anywhere, especially not in Washington D.C.

I also didn't know that they could determine the caliber fired. Does anyone know anything more about these? Who makes them? Are they widely deployed?

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bnkrazy
May 1, 2008, 01:41 PM
I hadn't heard much about them either. Here are some links:
http://science.howstuffworks.com/shotspotter.htm
http://www.shotspotter.com/products/index.html
http://en.wikipedia.org/wiki/Gunshot_Location_System

romma
May 1, 2008, 01:41 PM
Yep, they are deployed in numerous cities now.

Supposedly they can differentiate between gunshots and fireworks and backfires..

Perhaps different calibers too?

ochmude
May 1, 2008, 01:46 PM
I have absolutely no clue about what this article is specifically referring to. But I do know for a fact that we're quite successfully using acoustic locators to track indirect fire attacks in Iraq for the purpose of counter-battery operations. You can get a very accurate target location (enough to drop a 155 shell on it) before the enemy shot even hits the deck. I suppose it's possible that similar systems have been developed for law enforcement use, and possibly even analyse the sound to determine a caliber.

PercyShelley
May 1, 2008, 02:16 PM
OK, is there any reason that you couldn't record gunshots and then play them really loud back just to screw with the sensor array?

CypherNinja
May 1, 2008, 02:21 PM
My understanding is, no. There aren't any sound systems out there capable of reproducing a sound of that volume with enough fidelity.

And even if there were, $$$$$$$ is a bit much for a prank. ;)

Flame Red
May 1, 2008, 02:32 PM
I have heard that DC was amoung the first cities to have this system deployed. After all, they want to quickly track down all the pot shots aimed at our finer representatives.

Besides, everyone know that there are no guns in DC because they are banned, right? Maybe the criminals have not heard about that.

countertop
May 1, 2008, 02:33 PM
What I don't get is how these diffrentiate between all the various calibers, barrel lengths, bullet types, etc. There just seems to be too much variety in the sensors for them to be very accurate - I guess they could focus them in on typical gunshots - say a 9mm out of a glock, a 25 out of a Lorcin, a .380 (or a 7.62x39 in Iraq) but for others it would be tough to tell.

countertop
May 1, 2008, 02:38 PM
I have heard that DC was amoung the first cities to have this system deployed. After all, they want to quickly track down all the pot shots aimed at our finer representatives.

Installed when the Snipers arrived

BlackBearME
May 1, 2008, 02:39 PM
I doubt it necessarily differentiates between calibers. I'm sure, however, that they have patterned the gunshots from the standard service arms of the police. Therefore, when interpreting the data, if the sound/concussive force/The Force/whatever they use to measure it was greater, they could reasonably infer that the caliber fired was larger than the officers' caliber, without ever determining exactly what caliber was fired. Wow, that was verbose, but you get my point.

Regen
May 1, 2008, 02:40 PM
I could see the ability to differentiate between different calibers. The length of the barrel will have an effect on both pitch and duration of the sound of the gunshot. The caliber would only effect pitch. With enough samples of different ammo, you could build up a database of ammo, gun combinations.

Deer Hunter
May 1, 2008, 02:43 PM
I have slammed my car door in the car garage here at A&M and set off an entire level's worth of car alarms.

These sensors can be fooled.

svtruth
May 1, 2008, 02:58 PM
why police are not equipped with a gizmo containing a microphone, GPS and cel phone that automatically calls HQ when it detects a gunshot. Any discharge seems to need back up and if the officer were disabled, help would be on the way automatically.

Deer Hunter
May 1, 2008, 03:04 PM
Svtruth,

Funding perhaps?

S4Lee
May 1, 2008, 07:23 PM
There are mobile versions of (I guess) a similar tech as well, mounted on Humvees as sniper detectors:
http://www.gizmag.com/go/4497/

brickeyee
May 1, 2008, 08:24 PM
All they need to tell is that a different gun than the officers caused the initial shot.

Not hard to do at all if it was significantly different.

Grandpa Shooter
May 1, 2008, 08:56 PM
YES they are deployed in many major cities and NO they don't announce it to the general public.

WayneConrad
May 1, 2008, 09:08 PM
1. They don't work all that well.

2. By the time the police get there, the source of the gunshot is long gone.

Please see my post here (http://thehighroad.org/showthread.php?p=2800493) quoting the results of the Redwood City Field Trial (http://www.ncjrs.gov/pdffiles1/nij/grants/180112.pdf) (ncjrs.gov).

21H40
May 1, 2008, 10:42 PM
Birmingham news announced this week (maybe late last?) that we're supposed to get some. Oh boy... I can't wait for these to finally encourage all of the criminals here to "get a haircut and a real job" .... oh... they don't actually PREVENT murder? :rolleyes:

I feel for the cops on duty on the 4th and new years... if they have to respond to every "shooting" detected, they'll be REAL busy running in circles all night.

LAK Supply
May 1, 2008, 10:46 PM
HAHAHAHAHAHAHAHAHAHAHA! WHAT A USELESS POS THESE CITIES ARE BUYING!!! HAHAHAHAHAHAHAHA!











Sorry... couldn't help it. :o

LaEscopeta
May 2, 2008, 08:40 AM
I also didn't know that they could determine the caliber fired.Not the exact caliber, but likely classes of weapons and cartridge sizes. i.e. maybe tell the different from a medium size handgun (.380, 9mm, etc) and a full size rifle (.308, 7.62 x 54R, etc.)

OK, is there any reason that you couldn't record gunshots and then play them really loud back just to screw with the sensor array?I would think it would be pretty difficult to get a loudspeaker to produce the 150+ dB sound level of a gunshot.

HAHAHAHAHAHAHAHAHAHAHA! WHAT A USELESS POS THESE CITIES ARE BUYING!!! HAHAHAHAHAHAHAHA!And how would you know?

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