Oh i can see this being a
right laff on 5th Nov 2011....
The Safer Birmingham Partnership has begun to use communications technology developed in the US to locate the source of gunfire in the city. Birmingham is the first UK city to install the Shotspotter Gunshot Location System. The technology can locate gunshot fire within a 25-metre radius from up to 2km (1.24 miles) away. It …
right laff on 5th Nov 2011....
Seriously, what is more accurate:
"GUNSHOT DETECTED AT GPS LOCATION blah blah blah +-25M
"Is that the rozzers? Come quick. Some blokes in the kebab shop with a shooter!"
Now, maybe I'm being thick here, but I assume this is working through some sort of triangulation of the sound? Given that this is a city location, with plenty of buildings etc., surely the sound must rebound around so much as to make this very problematic? Also, doesn't this just make a silencer the object of desire in Birmingham?
before a silencer beats a one way ticket as the object of desire in Birmingham.
...that silencers aren't called silencers.
They're known as muzzle suppressors. The soft little "ptoo" that you get from the movies is a far cry from the resounding crack of a real "silenced" firearm. They're more useful for disguising the flash than the noise.
Am I the only one who burst out laughing at the description of the "silencer" in movies? "Ptoo" :D
A supressor acts by slowing down the projectile so that it does not break the sound barrier. The crack you refer to is the bulllet breaking the sound barrier.
With a subsonic round yoru only really going to hear the propellent going off and the air / gas wooshing out.
So correct in that a supressor does not silence the weapon, but does significantly reduce the acoustic effect of the projectile.
I think that a supressor would defeat this new toy from america.
No you're not, but that's actually a bang on description of the sound!
you have a wellrod, they really are silent.
well, except for the click of the firing pin hitting the primer.
for other guns; use subsonic ammo.
it works by allowing the hot gasses to expand into an enclosed space before venting to atmosphere at far lower pressure.
This is the same Birmingham who installed, and them deactivated, 280+ cameras to keep an eye on Muslim earlier this year. Three million pounds of technology wasted that time:
It's time Birmingham's police weaned themselves off hi visibility, hi risk, hi cost, hi failure, hi tech solutions and tried policing instead.
I can kind of understand why they deactivated them if they were high visibility being as many of them were supposed to be covert...
Paris, knows all about video surveillance
In response to privacy concerns it was stated that the system only started monitoring sound when it picked up a loud noise.
The more astute reader will not require my asking; Which came first the chicken or the egg?
As always some research is in order rather than trusting in press releases.
in that they could be said to "only monitor speeds when high speed is detected", ie they (generally) only record/transmit speed/numberplate data* when their internal logic is activated by a speed >x.
It would be trivial and the best technical solution to have each of the microphones in the network sit dormant until activated by a sound >XdB, and then they begin processing/recording the sound input and transmitting the appropiate data to HQ.
I imagine the processing involves a little DSP to differentiate 'gunshot' type cracks from all other loud noises, and precise timing of the sound against something like a GPS clock. If you get the precise time that a given sound has reached at least 3 known points, the origin can then be calculated.
*referring to 'traditional' Gatso-type cameras, not ANPR or other hi-tech trickery.
According to the Beeb news website (http://www.bbc.co.uk/news/uk-england-birmingham-11950517), before the 12.07 update and after I enquired about it, the police were apparently quoted to saying that surveillance was not an issue as the sensors recorded decibels and not voices. Needlessly to say I was rather confused and worried by this claim. To add to this rather odd claim, the BBC news website included a clip which clearly showed that the sounds are recorded in full glory, can displayed as waveforms, analysed, and played back.
Since you only get timing differences between receivers (you don't know exactly when the shot was fired) you need 4 points to work out where the shot came from. The first two give you one value and you get an extra one for each additional receiver.
will start using silencers now?
as yesterday we hear 400 officers are going in Birmingham, due to the spending review. Doubtless this is their PR fightback ...
Well if that means there are fewer plod to harass photographers, and waste their and every body elses time nicking people for a puff of a joint, I won't cry.
Hang on, that was just a misfiring minicab, never mind.
"Gunshot detected, industrial estate, Digbeth..."
No, that was a lorry running over a discarded pallet.
Yes, I can see this going slightly wrong.
'There's been an explosion!'
Thanks, Shotspotter. If only we could have somehow prevented it.
Lets see. From newspapers I gather that the majority of inner city shootings are gang/drug related account settling so they are detecting gang on gang shootings which, quite honestly, I couldn't give two hoots about. Now compare the number of these shootings with the number of muggings which occur in Birmingham. Now think which would be more welcome by the general public, extra police patrolling the streets as a visible deterrent to prevent crime or detecting after the fact that some low life has shot on of their peers?
I think the Safer Birmingham Partnership need a very big clue bat.
Just get a large roll of bubble wrap and a pallet truck in Handsworth and run the bubble wrap over with said truck. The police will think world war 3 has started.....
calls is "forklift ammunition".
I thought that guns were outlawed in the UK? How is this possible?
i has teh gunz.
Blah blah, coppers on beat, blah blah... waffle, outrage, in my day waffle, clip round the ear...
Seriously though, this sounds like a huge waste of time and money that would be far better spent on getting more coppers out of the station instead of stuck behind desks or on the sick. It's really rather scary how thin the cover is for the urban areas I know of (and I know of plenty, just don't ask me how)
The real benefit of installing this (no doubt expensive) system is to the employment prospects of a handful of Birmingham rozzers when they take their early retirement.
"Yes, chief inspector, I'm sure your purchase of this wonderful system will lead to the future expansion of our UK sales team"...........
Back handers are my only explanation for installation of expensive high-tech crap like those huge motorway signs which tell me "beware of spray" when is it pissing down or "14 minutes to J14" when I have no idea where J14 is.
Like all technologies it works but not in the magic/movie sense that this article implies. I can see we're going to have some fun with this system -- it responds to the crack of the gun being fired so I can see a future in tin cans / carbide and propane / air mixtures ("bird scarers") . Certainly if I were planning a hit I'd want to swamp the system, "just in case".
You've got some ace salesmen in the UK. They can sell government *anything*!
We have this system in some of the more crime-ridden areas of the city nearest to me. It DOES cost a lot, break down a lot and yes, it does find gunfire. What it does NOT do is operate effectively - CERTAINLY not effectively for the cost.
Baton Rouge, LA USA. initial cost $3.5million, annual maintenance costs over $450,000 to cover an area roughly EIGHT square miles. Birmingham should save the money and, perhaps, spend it on more [leather shoes*] on the ground.
<excerpt>In an April 2008 e-mail, Nick Pizzalato, network administrator for the city-parish’s Information Services department, sent an e-mail to a representative of ShotSpotter.
“How can I convince the police that this is going to help them?” Pizzalato wrote. “They don’t want the system and they don’t think it’s going to be any benefit. I guess when I say they I mean the dispatchers because the field officers don’t even know about it yet.” </excerpt>
* unless, of course, the Birmingham constabulary actually DOES wear boots. Then, the old adage stands as is.
but only on subsonic rounds. if you are using slow rounds you do only get a pfffft.if you do use supersonic rounds the you hear the bullet breaking the sound barrier mostly.
Not so much Bang, Bang as Bung, Bung?
What's the betting that the local kids will play audio recordings of gunshots near to these microphones 'for a laugh'?
How long before they decide to feed in a voice print and try to match "known criminals".... and then monitor "potential terrorists"... and then say "these are required for the detection of serious and organised crime"... and then, "we heard you say you wanted to blow up the airport if they didn't stay open during the snow-storm!"
1. Fun with bursting paper bags
2. How long before anyone notices that these mikes are always on, recording converstaions
recording conversations as well.
<- need a gun icon
Yeah, because we wouldn't want anyone monitoring communications or anything, that would be really bad.
I seem to remember these devices first appeared in the dystopian near-future setting of the classic video game Deus Ex. The response was simple, of course, people just killed each other with crossbows and swords instead.
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