Slashdot Mirror
Seeing Through Walls
An anonymous reader writes "Researchers at MIT's Lincoln Lab have developed new radar technology that provides real-time video of what's going on behind solid walls. 'The researchers’ device is an unassuming array of antenna arranged into two rows — eight receiving elements on top, 13 transmitting ones below — and some computing equipment, all mounted onto a movable cart. But it has powerful implications for military operations, especially "urban combat situations," says Gregory Charvat, technical staff at Lincoln Lab and the leader of the project.' ... each time the waves hit the wall, the concrete blocks more than 99 percent of them from passing through. And that’s only half the battle: Once the waves bounce off any targets, they must pass back through the wall to reach the radar’s receivers — and again, 99 percent don’t make it. By the time it hits the receivers, the signal is reduced to about 0.0025 percent of its original strength. But according to Charvat, signal loss from the wall is not even the main challenge. "[Signal] amplifiers are cheap," he says. What has been difficult for through-wall radar systems is achieving the speed, resolution and range necessary to be useful in real time (PDF).'"
Is the amount of radiation dangerous? What about reflections? Not that it would matter in a military context but it might restrict its civilian applications.
In the future, I guess snipers will have to carry a $ 5 roll of aluminum foil, to block the multimillion dollar real time radar.
Two points:
A) This is different than x-ray because it is using the reflection, not a film or detector on the other side of the object.
C) The image created is not a 3D image like what you would expect if the wall were glass, instead it detects distance to objects. So what you get is like a overhead map, as if you were playing Zelda and or had the Harry Potter marauder's map. Which may be more useful in some situations.
"First they came for the slanderers and i said nothing."
Who wants to play the special mission where you are the guy pushing around the cart with all the antennas sticking out of it?
With a 20cm signal, you can't tell a human from an amorphous blob. The only thing you could get from attitude control is a very rough estimate of height. Besides, if they wanted such a capability, it would be better to just stack four of these, with a commensurate increase in hardware and processing power.
In English, they are called X rays (which is actually the name Röntgen gave to them).
The Tao of math: The numbers you can count are not the real numbers.
So it is good at locating people moving behind a wall. Can you tell if the person is armed?
If you also display stationary objects, is the blob in the corner a person or a filing cabinet?
Look at the size of the thing. I do not see a tactical unit trundling something that big so that they can see 20m through a wall. I am not sure but if you decrease the size of the antennas your power and resolution goes down. Also how much power does the radar and computers use? How long would it last on batteries?
This technology is unconstitutional. I have zero faith the arrogant slashdot crowd to actually comprehend it until it's too late. It's all fun and games until someone's eye get's put out.
The Fourth Amendment (Amendment IV) to the United States Constitution is the part of the Bill of Rights which guards against unreasonable searches and seizures, along with requiring any warrant to be judicially sanctioned and supported by probable cause. It was adopted as a response to the abuse of the writ of assistance, which is a type of general search warrant, in the American Revolution. Search and arrest should be limited in scope according to specific information supplied to the issuing court, usually by a law enforcement officer, who has sworn by it.
The only people working on this are future treasonous oath breakers. The same ones who allowed the banksters to steal our monetary system, the same ones who allow electronic voting, sound weapons, fios splitters, wiretapping, and all the other full spectrum of unconstitutional bullshit.
If you think I am full of shit, explain to me why I should obligated to obey any law coming from the establishment when the establishment doesn't follow any rule of law anymore, and in fact promotes fraud, theft and murder? This is the exact reason the economy won't recover, the trust has been purged completely from the system along with peoples life savings, all at the same time the establishment cracks down on the small guy protesting, not one motherfucking bankster has gone to Ft. Leavenworth.
I am an honorably discharged veteran, I might not be the smartest fucker in the world, but I know treasonous oath breaking shit when I see it. You want this country to recover, you better start putting the oath breaking officials and their punk ass fucking foreign and corporate CEO friends and their agenda's and treaties in Ft. Leavenworth.
This is the path to darkness, death, destruction and marital law. and if it goes mainstream, you can be sure taxpayers will pay for their own incarceration and targeting.
The path to light, life, health and a constitutional republic will only be reached if the Oliver North's, the Negropontee's are flushed from the Pentagon, NSA, CIA and halls of power. The DHS will need to be de-activated as it is in 100% opposition to the US Constitution. The banks who have over leveraged must fail, their CEO's imprisoned for fraud, theft, and treason (for the Senators who swore an oath to regulate the monetary system)
If you don't care about the US Constitution, or rule of law, then frankly you aren't my friend (you are actually my sworn enemy) and I don't give a shit about your fucking life, I mean you are really only one little tiny law away from being on a hit list. Even if you think I am wrong, the fact I am wired to think it; should scare the crap out of your arrogant educated asshole. So go see your shrink, and know I know my place in the universe bitch.
It's all fun and games until someone get's their eye put out.
Would you like this technology used on your daughter, son, mother, father or wife, husband, or pet?
How about you fucking arrogant educated assholes take your "see through walls tech" to Fukushima, and help them fix the problem? No? It won't work?
This technology is useless except for enslavement of humans. All you laughing fools, giggling nerds, are the future slaves.
You lazy motherfuckers couldn't even stop electronic voting.
The person who designed the radar was posted before, but this was about his PhD project. Here is the link and you too can build your own SAR (as long as you can read his cat scratch of notes on his blog)
http://hardware.slashdot.org/story/10/06/18/1350259/diy-synthetic-aperture-radar
Also on his blog, you will see similarities to what he developed for his PhD and what he is working on now.
http://www.mit.edu/~gr20603/Dr.%20Gregory%20L.%20Charvat%20Projects/Synthetic%20Aperture%20Radar%20(SAR).html
Oh, and I am not a groupie. I happen to actually know Greg.
It's called coherent integration gain. It's done entirely digitally in a modern radar such as this and can in theory allow you to detect pretty much any signal no matter how weak [there are practical limits of course...] The whole radar they've described probably has a BOM cost of less than $200,000. The real gotcha is labor to make it work, not the material cost. That'll cost millions [probably >$10Million, you could find out if you want to dig through some defense contracts and find the value of this one...] but so did your new iPhone 4S. The difference is that your iPhone 4S is going to have millions made this not so much. If the government wanted to build 100,000 of these, the cost would probably drop to around $50,000....
Here's the idea:
1) You transmit N identical pulses of radar waveform (probably an LFM or NLFM waveform for this application)
2) They bounce off the target and return to the radar
3) You receive them. They are WAY below the noise figure (say 50db). No amount of normal filtering will get them back. You have to analyze the noise for something that isn't "noise" like....
4) You use a matched filter that has a maximum output when the input signal is exactly the LFM you originally sampled to "pulse" compress the signal
5) If you're lucky the matched filter output has gotten you 20-30 db of gain because it's looking on a single pulse basis for the exact signal of interest. That 20-30db gain DOESN'T apply to the noise, because the noise won't match the matched filter [random vs determinisitic], therefore you've gained 20-30db of SNR.
6) Now remember you transmitted N pulses. Why not look for a signal across all of those? That's the next step. For this application they'd probably use Doppler processing. Turns out that if you do this properly you get gain on the desired signal equal to the number of pulses, so if you transmit thousands you can get that remaining 20-30db needed to make the signal >15db SNR which is the usual minimum for reliable detection in thermal noise.
It's really straight forward. The challenges here are not in that part of the design. That part is easy..
The challenges are:
1) Making it realtime (Coherent processing doesn't work when targets lose coherency that happens when they move "too quickly"). This limits the number of pulses you can use to make useable system
2) Dealing with the Dynamic range between the (very) STRONG wall return and the very weak internal targets. [Very expensive ADCs and RF amplifiers can help, they've also apparently added a doppler filtering step in analog which is interesting.... But fundamentally it's a pain]
3) Target classification. The military could care less how many TV and appliances you have. Unfortunately those will show up as targets behind the wall too...
4) Making it small enough and draw a reasonable enough amount of power to be vehicle mounted
===> If you fix #1 with more output power or a larger antenna you run into this problem.....
4) Having enough resolution to actually differentiate 2 separate targets. Without going into the details this becomes problematic for short range radars like this....because you want to see things that are on order 1ft x 1ft.. Radar is much better at seeing Planes and Tanks...
When executing a warrant all reasonable tools should be used.
The police state in the US is WAY beyond using anything resembling that kind of restraint. They are now accepting collateral deaths of police and innocent civilians as justified to combat recreational drug use. Expansion of those powers in the name of fighting "lone wolf terrorists" is a frightening prospect.
"Somebody has to do something. It's just incredibly pathetic it has to be us."
--- Jerry Garcia
Interesting how you neglect to mention the deaths of police and innocent civilians caused by the purveyors of recreational drugs.
Because it's irrelevant to the discussion. Those are not actions sanctioned by the state (although the state's very prohibitionist stance on recreational drugs has certainly precipitated the environment in which black marketeers become violently defensive of their activities).
So when the police have to deal with these gangs that do so using heavily armed, highly trained units.
I won't excuse the actions of the state when they have created the very atmosphere of violence they are claiming to combat.
If you don't want to get shot when an SRU shows up then don't pull a gun.
That doesn't help most of the time, and especially when you aren't given an opportunity to identify the group that's invading your home before they open fire on you.
I do not see how the use of radar expands the US anti-terrorism powers.
It doesn't (it's hard to imagine how they could be expanded further). It expands surveillance powers, whatever the excuse. And it does so at the expense of freedom and 4th amendment protections.
"Somebody has to do something. It's just incredibly pathetic it has to be us."
--- Jerry Garcia