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Tracking gunfire with a smartphone

Meh, I'm going to say this is pretty far off from working correctly.


Also can you detect direction from only supersonic cracks? I thought it was a non-directional sound. Please correct me if I'm wrong, but isn't the report of the rifle needed to detect the sound as well? If the shot is suppressed, can you find the direction just by the supersonic crack?
 
Diesel, i believe the sound triangulation technology does exist, though probably not accurate when based on a single smartphone.

Google:

EARS® is our battle proven Sniper Detection solution which can be used by mounted and dismounted soldiers. It audibly cues soldiers with the direction and distance of sniper shot in less than a tenth of a second and around a 360° view, even when used on a vehicle moving at speeds over 50mph



Meh, I'm going to say this is pretty far off from working correctly.


Also can you detect direction from only supersonic cracks? I thought it was a non-directional sound. Please correct me if I'm wrong, but isn't the report of the rifle needed to detect the sound as well? If the shot is suppressed, can you find the direction just by the supersonic crack?
 
Diesel, i believe the sound triangulation technology does exist, though probably not accurate when based on a single smartphone.

Google:

EARS® is our battle proven Sniper Detection solution which can be used by mounted and dismounted soldiers. It audibly cues soldiers with the direction and distance of sniper shot in less than a tenth of a second and around a 360° view, even when used on a vehicle moving at speeds over 50mph



I understand that, I'm speaking more to this

You are walking down the street with a friend. A shot is fired. The two of you duck behind the nearest cover and you pull out your smartphone. A map of the neighborhood pops up on its screen with a large red arrow pointing in the direction the shot came from.
 
can you detect direction from only supersonic cracks? I thought it was a non-directional sound. Please correct me if I'm wrong, but isn't the report of the rifle needed to detect the sound as well? If the shot is suppressed, can you find the direction just by the supersonic crack?

You can tell from the snap even with peltors on. It IS extremely difficult (which is why we are developing all the cool gear to make it easy) but sound like that still isn't exactly "non-directional". What makes it difficult is the speed of the bullet; your ears/brain determine the direction of a sound by the delay from one ear registering a sound and the other hearing the same sound then the brain doing the triangulation (I bet having the experience of it happening helps condition the brain to figure it out). A supersonic crack has the same delay going on even if the window is shortened. These systems probably use a similar method for the triangulation (in the article it mentions multiple sensors), I've seen them before, but never been the one setting them up or running them, so I've never learned up on them. They are currently way too bulky to use dismounted, which is why the smartphone method is pretty awesome. This is definitely something to get excited about.
 
Thanks, SD. The way I was thinking was that the micro bursts that cause the constant cracking might get in the way of our mind being able to process the sounds direction. I know it makes it harder if it's coming form a suppressed rifle.


Thanks again for taking the time to explain it.
 
No worries at all, reading the article it sounds like the capability will be part of a small network between team members- "Like the military version, the smartphone system needs several nodes in order to pinpoint a shooter’s location." So you and your buddies would basically all need to have a device on your person, running the program and linked to each other. I would assume that the more nodes you had, the better the fidelity of the program telling you a refined direction or even a triangulation to a point on a map.

The benefits of a suppressor (assuming he wasn't using subsonics which would presumably defeat the system and your ears handily) would be the lack of flash and initial report of the gun that allows someone to pinpoint your fire. Suppressors are bad ass for making people have a much harder idea where the are shot from from ("from the left!" doesn't do a guy much good) and where to engage. Couple that with some field craft and things get awesome for the sniper, and terrible for the "snipee" heh
 
All the military systems triangulate the source based on sonic boom. A sonic boom is cone shaped and the cone angle depends only on velocity. You need 4 microphones minimum and the military systems work extremely well. It is simple to calculate range(from calculating bullet speed and measuring time until the muzzle report reaches the microphones)very accurately and you can also approximate the caliber of the projectile.

It's be easy to make a small sensor with microphones that plugs into a phone and does this, that's what the article above describes.
 
To tell the speed of a bullet with only microphone, the round has to be supersonic so you can calculate the sonic boom compared to the muzzleblast. You also have to have a VERY precise clock. Direction finding with one microphone does not seem possible.

Now, the fact that the hypothetical "You and your friend" situation involves two people makes me believe that there are two phones and therefore two microphones involved via networking the two phones to come up with a solution. Still, I could see direction formula pretty easily, but distance to any degree of accuracy would require the two microphones to pretty far apart or maybe knowing the muzzle velocity of the round fired.
 
To tell the speed of a bullet with only microphone, the round has to be supersonic so you can calculate the sonic boom compared to the muzzleblast.

You calculate direction by measuring the shape of the sonic boom shock wave. The muzzle report cannot reliably be picked out of background noise by a computer algorithm while a shock wave can be. Knowing the cone angle of a shock wave you can calculate the bullet speed extremely accurately. The muzzle blast is only used for calculating range when the system can isolate the muzzle blast.

The ground based systems have a microphone array the size of a basketball and a speaker that reports a clock direction(relative to the vehicle), range(if the muzzle blast was detected), and sometimes a "high" or "low" to help pinpoint the source in mountainous or Urban terrain.
 
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You calculate direction by measuring the shape of the sonic boom shock wave. The muzzle report cannot reliably be picked out of background noise by a computer algorithm while a shock wave can be. Knowing the cone angle of a shock wave you can calculate the bullet speed extremely accurately. The muzzle blast is only used for calculating range when the system can isolate the muzzle blast.

The ground based systems have a microphone array the size of a basketball and a speaker that reports a clock direction(relative to the vehicle), range(if the muzzle blast was detected), and sometimes a "high" or "low" to help pinpoint the source in mountainous or Urban terrain.

No doubt measuring the shockwave is better, but that requires multiple microphones and a clock calculating rediculously precise time. Neither of which a cell phone can do (that I know of).
 
the boomerang system that are currently used on trucks overseas works very well in pinpointing gun fire especially when there are a few guys shooting full auto I don't see why they couldn't miniaturize the microphone antenna and use a program out of a pda or something like that.
 
PS: google "boomerang" for the common vehicle mounted system.

I was going to say the technology is there, but getting it in a phone might be hard, the boomerang utilizes seven seperate microphones, but it is very accurate and effective.
 
Charleston, SC has a system in place to detect, and locate the source of gunshots. They mount the hardware on telephone poles.

It would take a multitude of handheld devices to detect, and locate a gunshot. Ultimately I don't believe this technology will be viable. It may work in a lab. They would be far better off focusing on smaller, permanent placement, devices.

Chip
 
Three things

I would first have to buy a "Smart Phone";

I try to avoid walking with my girlfriend in neighborhoods where gunfire is an issue;

Lastly, if I heard a gunshot while walking with my girlfriend I'd know exactly where it was coming from ----

My wife :)