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Seeing Through Walls

Posted by Soulskill on from the life-imitates-quake dept.

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).'"

163 comments

  1. 4th amendment by Anonymous Coward · · Score: 0

    what 4th amendment?

  2. So what if your standing IN FRONT of the wall? by wisebabo · · Score: 3, Interesting

    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.

    1. Re:So what if your standing IN FRONT of the wall? by Mindflux0 · · Score: 1

      They were walking around in front of it. Leads me to believe it's not particularly dangerous. Maybe extended exposure is bad though.

    2. Re:So what if your standing IN FRONT of the wall? by phantomfive · · Score: 4, Informative

      They are using Microwave, which is non-ionizing, so it is not so dangerous. You would start feeling the heat before you got any radiation damage.

      --
      "First they came for the slanderers and i said nothing."
    3. Re:So what if your standing IN FRONT of the wall? by stms · · Score: 5, Informative

      It's non-ionizing radiation so it's about as dangerous as your cellphone. This is an interesting and informative radiation chart https://www.xkcd.com/radiation/

    4. Re:So what if your standing IN FRONT of the wall? by wagnerrp · · Score: 3, Informative

      Eh? As you said, it's non-ionizing. The heat is the radiation damage.

    5. Re:So what if your standing IN FRONT of the wall? by tinkerton · · Score: 0

      The chart doesn't cover the problem at hand. If you walk in front of the (active) radar of a fighter plane, it will kill you , and it will do so inside out. It won't start by burning your skin.

    6. Re:So what if your standing IN FRONT of the wall? by tinkerton · · Score: 1

      I don't know the power of the apparatus being tested in the article, but the person walking around was behind a wall, which reduces the dose to 1%.

    7. Re:So what if your standing IN FRONT of the wall? by phantomfive · · Score: 1

      True, but not all heat is damage. You will likely feel a lot of heat before you get any real damage.

      --
      "First they came for the slanderers and i said nothing."
    8. Re:So what if your standing IN FRONT of the wall? by wisebabo · · Score: 1

      By the way, I'm sorry for the incorrect used of the word your, it should be you're as in "you are". I dislike it when people use it incorrectly so my apologies. I was in a hurry (but aren't we all?)

    9. Re:So what if your standing IN FRONT of the wall? by mcavic · · Score: 1

      It's not that simple. According to some quick reading, microwaves can cause heat damage to inner tissues and to the eyes that isn't immediately apparent. And military-type microwave use has been known to cause noticeable health effects since WWII, which was confirmed in the 70s.

    10. Re:So what if your standing IN FRONT of the wall? by slydder · · Score: 0

      does it really matter? we are talking about the military using this to find people behind walls to they can kill them more effectively. the only possible problem would be to hostages and other non-coms. so if there are non-coms in front of the wall then they are not where they should be and all hossies would be behind the wall where very little radiation will reach them.

      --
      IT Admins Group: Where you decide the content
    11. Re:So what if your standing IN FRONT of the wall? by Joce640k · · Score: 1

      They were walking around in front of it. Leads me to believe it's not particularly dangerous.

      People used to go down to Vegas for the weekend to watch the atomic bombs going off...

      --
      No sig today...
    12. Re:So what if your standing IN FRONT of the wall? by Misagon · · Score: 2

      Non-ionizing means that it does not directly cause DNA damage.

      However, it has been shown in tests that microwaves of certain frequencies can have other effects on human cells other than heating them up. These effects include increasing the uptake of glucose and breaking the cell's membrane which would allow the cell to be killed by albumen in the blood.
      Not all frequencies in the microwave band are equal, though. Only some frequencies have been tested.

      --
      "We mustn't be caught by surprise by our own advancing technology" -- Aldous Huxley
    13. Re:So what if your standing IN FRONT of the wall? by Anonymous Coward · · Score: 0

      Did you read TFA?

      They beam these microwaves through brick walls, what makes you think they don't penetrate the skin and do damage to the body?

      When you feel the heat you have already been skewered by the microwaves quite a lot (the skin is most likely somewhat less effective at blocking microwave radiation than, say the aforementioned brick wall) and there are considerably volatile targets that are shielded by your skin.

    14. Re:So what if your standing IN FRONT of the wall? by atisss · · Score: 1

      So, most of it's energy is heating the wall?

      I would hide some small explosives on the outer side of wall in order to notice if somebody is peeking in

    15. Re:So what if your standing IN FRONT of the wall? by icebraining · · Score: 1

      Yes, but in this case the "people" are the actual researchers, no some random Joe.

      --
      Dilbert RSS feed
    16. Re:So what if your standing IN FRONT of the wall? by dotancohen · · Score: 1

      Eh? As you said, it's non-ionizing. The heat is the radiation damage.

      Sounds more like a feature than a bug. Remember: military applications.

      --
      It is dangerous to be right when the government is wrong.
    17. Re:So what if your standing IN FRONT of the wall? by dotancohen · · Score: 1

      I don't know the power of the apparatus being tested in the article, but the person walking around was behind a wall, which reduces the dose to 1%.

      Which is still 100 times larger than is needed for regular detecting equipment, as the "dose" needs to cross the wall again. So the "other side" dose is still significantly strong.

      --
      It is dangerous to be right when the government is wrong.
    18. Re:So what if your standing IN FRONT of the wall? by EdZ · · Score: 2

      Microwaves are not made of magic. They do not cook things from the 'inside out', as advertisements would have you believe. Standing in front of a high-power radar antenna will heat your from the nearside to the farside, with the power and wavelength determining the heat gradient.

    19. Re:So what if your standing IN FRONT of the wall? by Anonymous Coward · · Score: 0

      Yes, but in this case the "people" are the actual researchers, no some random Joe.

      That was also the case with the atomic bomb detonation experiments. Turns out the researchers had less knowledge of the safety limits than they thought they did...

    20. Re:So what if your standing IN FRONT of the wall? by Curunir_wolf · · Score: 1

      does it really matter? we are talking about the military using this to find people behind walls to they can kill them more effectively.

      Really? You really think that's all this is going to be used for? How naive.

      The natives are becoming restless, they need stuff like this to quell a rebellion, flush out the leaders, and protect the establishment. They've already started rolling out unmanned drones for use by the police. They could start deploying the armed versions whenever they want.

      --
      "Somebody has to do something. It's just incredibly pathetic it has to be us."
      --- Jerry Garcia
    21. Re:So what if your standing IN FRONT of the wall? by Dunbal · · Score: 1

      does it really matter? we are talking about the military using this to find people behind walls

      You are naive enough to believe that this will never be used by the government on civilians EVER, right? The military doesn't really need something like this because if they are really worried about what's behind a wall they just blow it up. This is 100% for law enforcement use, which is where the government wants to know what's behind the wall but is not allowed to do so by law.

      --
      Seven puppies were harmed during the making of this post.
    22. Re:So what if your standing IN FRONT of the wall? by tinkerton · · Score: 1

      I doubt if it's 100 times larger. I don't have time to compare, but it will be a lot less. One trick to reduce the wattage is to take much more time measuring, and a predecessor of the radar in the article took many seconds. This radar also measures slower than the standard.

    23. Re:So what if your standing IN FRONT of the wall? by nedlohs · · Score: 2

      Sure if you want to save the military their next step.

    24. Re:So what if your standing IN FRONT of the wall? by tinkerton · · Score: 1

      Obviously. And also you don't need cooking temperature.

    25. Re:So what if your standing IN FRONT of the wall? by Anonymous Coward · · Score: 0

      Eh? As you said, it's non-ionizing. The heat is the radiation damage.

      Sounds more like a feature than a bug. Remember: military applications.

      Yes, but it won't be long before local police departments want this as well.

    26. Re:So what if your standing IN FRONT of the wall? by Anonymous Coward · · Score: 0

      They could start deploying the armed versions whenever they want.

      Especially now that there's a huge contingent of warhawks who are adamant that the President can order the death of a citizen without oversight. The next boundary to test is whether the President has to wait until the target goes on vacation or not.

    27. Re:So what if your standing IN FRONT of the wall? by tinkerton · · Score: 1

      many proteins denaturate over 41 degrees celsius. It might be reversible when the temperature is not too high though. If you heat part of the body with microwaves up to 50 degrees celsius, that could already do a lot of permanent damage. And I doubt if you'll feel much heat when it happens.

    28. Re:So what if your standing IN FRONT of the wall? by Smallpond · · Score: 1

      These effects include increasing the uptake of glucose...

      That's it. I'm suing the government for my obesity.

    29. Re:So what if your standing IN FRONT of the wall? by Anonymous Coward · · Score: 0

      True, but consider that your skin has air cooling. This means that that, depending on the wavelength, you can have the hottest point somewhere under the skin.

    30. Re:So what if your standing IN FRONT of the wall? by john82 · · Score: 1

      many proteins denaturate over 41 degrees celsius. It might be reversible when the temperature is not too high though. If you heat part of the body with microwaves up to 50 degrees celsius, that could already do a lot of permanent damage. And I doubt if you'll feel much heat when it happens.

      Your core temperature is 37 C (98.6 F). But you don't think someone would notice 50 C (122 F)? If that was bathwater, you'd be scalded.

    31. Re:So what if your standing IN FRONT of the wall? by Anonymous Coward · · Score: 0

      Source?

    32. Re:So what if your standing IN FRONT of the wall? by tinkerton · · Score: 1

      I wonder. Skin is always a bit different. What temperature would you consider too hot for tea? 60 degrees is well acceptable then. But then you drink it in small quantities that cool down quickly.

    33. Re:So what if your standing IN FRONT of the wall? by phantomfive · · Score: 1

      No, this would have been extremely useful in urban warfare, for example, in Fallujah. The military doesn't go around blowing up every building they com across, you know.

      --
      "First they came for the slanderers and i said nothing."
    34. Re:So what if your standing IN FRONT of the wall? by gumbi+west · · Score: 1

      Have you seen this?

      So much for non-ionizing radiation doesn't ionize.

    35. Re:So what if your standing IN FRONT of the wall? by orangesquid · · Score: 1

      FUCKEN MICROWAVES, HOW DO THEY WORK?!

      Actually, microwaves are made from unicorns and enchanted hobbits, so technically they are, in a sense, made of magic.

      They cook oils only on the surface because the resonant frequency is a good match. This is the cause of much of the food spattering in a microwave oven. The heat will pass gradually into the oil from the surface by convection, but the surface gets a LOT of heat by absorption. Much food has a high water content... and microwaves will heat water, but are not nearly so good of a resonant match. Thus, a depth of about half an inch to an inch will absorb a lot of the microwaves, and pass the heat by convection deeper into the food. If you thaw something frozen in a microwave or try to cook a casserole in a pan and not a casserole dish, this becomes obvious. Some of the "inside out" apparent effect is due to microwave hot spots;.... so now we have turntables so that the standing wave issue is less significant.

      It's not too hard to learn to understand, but that "inside out" myth still exists.

      For a human, the skin and blood vessels near the surface manage to absorb and spread a lot out environmental heating from the sun---as evolution would suggest is simply logical. Unfortunately, strong microwaves will have more penetration than that, causing tissue damage below the skin. Still no inside-out cooking of people, though. :D

      --
      --TheOrangeSquid Is it any wonder things seem so awry? We swim in a sea of confusion and don't have to think to survive
    36. Re:So what if your standing IN FRONT of the wall? by treeves · · Score: 1

      No, no, no. The CORPORATIONS are responsible for your obesity. The Government is doing their best to protect you from the evil corporations (and from yourself). Just let them do their job and you'll be fine.

      --
      ...the future crusty old bastards are already drinking the Kool-Aid.
    37. Re:So what if your standing IN FRONT of the wall? by TheCouchPotatoFamine · · Score: 1

      what the hell is that non-sense? Zero point? really? As much as the guy found a trippy way to produce flame, i doubt it has ANYTHING to do with this discussion.

      --
      CS majors know the time/space tradeoff, but they never get taught the 3rd, crucial, tradeoff of the set: comprehension!
    38. Re:So what if your standing IN FRONT of the wall? by Anonymous Coward · · Score: 0

      Wouldn't too sure. Soon to come to a police force near you.

    39. Re:So what if your standing IN FRONT of the wall? by PwnzerDragoon · · Score: 2

      Mythbusters already disproved that. They tried to cook a chicken with a radar dish and nothing happened. And as someone else already pointed out, microwaves don't cook from the "inside out".

    40. Re:So what if your standing IN FRONT of the wall? by optimism · · Score: 1

      Microwaves are not made of magic. They do not cook things from the 'inside out', as advertisements would have you believe.

      I've never seen an advertisement claiming that microwaves cook from the "inside out". Have you?

      Microwave ovens can seem to cook some foods from the inside-out because:
      1) Many foods have a denser interior, which absorbs more of the energy. The classic example is a jelly donut.
      2) The outside of the food is cooled by convection and conduction with its environment; the inside is not.

      I dunno if #1 applies for human bodies, but #2 certainly does.

      Also consider that your heat receptors (nerve endings) and your cooling system (sweat glands) are both on your skin, not on your insides. So microwave radiation can easily damage your insides before your skin registers it as "damaging".

    41. Re:So what if your standing IN FRONT of the wall? by memnock · · Score: 1

      I had a similar first thought to this. It seems like a lot of equipment developed for "military" use is more along the lines of military/security, thus applicable for use by police forces. Beyond anti-aircraft or ballistic missiles, a lot of the tech seems to become police-issue. So where is the pro-democracy tech to keep police from abusing this stuff once they get their hands on it? Every time I see a "new military tool" I picture police using it to squash protesters.

      --
      "To stop the terrorists."
    42. Re:So what if your standing IN FRONT of the wall? by phantomfive · · Score: 1

      I'm glad you corrected me with your quick reading.

      --
      "First they came for the slanderers and i said nothing."
    43. Re:So what if your standing IN FRONT of the wall? by gumbi+west · · Score: 1

      radio waves are very low power per photon and so are called non-ionizing radiation under the theory that what applies to pure metals must apply to everything else.

      But in the video radio-waves are ionizing water. When the radio waves ionize the water it releases hydrogen and oxygen. These then combine right above the test tube to form a flame in the reverse reaction.

      Is radio safe because it is non-ionizing? Before I saw this video, I would have said yes, only heating is an issue. Afterwords, I'm not so sure.

    44. Re:So what if your standing IN FRONT of the wall? by tinkerton · · Score: 1

      After thinking it over though I'm starting to doubt some things. It's very hard to heat up part of the body with a few degrees because we've got very good cooling. And we've got good cooling in part because it's very damaging if we heat up too much. So you'll need a lot of energy transfer before the heat builds up so quickly it can't be distributed fast enough - or you need a part of the body that has little blood flow - hence the warnings about fertility. So while the fire control radar of a fighter jet can be pretty powerful, I'm really starting to wonder if it can kill you. I can't find any references to it.

    45. Re:So what if your standing IN FRONT of the wall? by vandamme · · Score: 1

      Yes, military microwaves are more dangerous than civilian microwaves. Not because they are military and scary-sounding, but because if you stand in front of a radar antenna feed horn putting out kilowatts of average power, it will produce more heating damage than your microwave oven leaking microwatts. I've worked BEHIND such radar antennas for 41 years, and my eyes are pretty good and I don't have cancer. I was already stupid before I started working, though.

  3. hmmmm coming soon to an airport near you... by Anonymous Coward · · Score: 0

    Whats the effect of radar on people ?

    1. Re:hmmmm coming soon to an airport near you... by siddesu · · Score: 1

      It seems the primary application is the American military. Why do you think anyone in that camp cares about what will happen to the targets for the minute or two before they are shot from a nearby helicopter?

    2. Re:hmmmm coming soon to an airport near you... by wagnerrp · · Score: 1

      About the same as a heat lamp.

    3. Re:hmmmm coming soon to an airport near you... by Anonymous Coward · · Score: 1

      Seeing behind walls? Right, military ... no way they'd ever use that in the "homeland". Oh wait, they already have trucks that do similar things with unclear health effects roaming US streets.

    4. Re:hmmmm coming soon to an airport near you... by siddesu · · Score: 0

      Well, I don't presume who the targets are. Be that as it may, how many of those roentgen trucks are on the road really? I've seen the ads, but if spying was really effective and prevalent, wouldn't some info about the scale leak already?

    5. Re:hmmmm coming soon to an airport near you... by wagnerrp · · Score: 1

      A roentgen is a unit of measurement for ionizing radiation. Since these do not output any, they cannot be described as such.

    6. Re:hmmmm coming soon to an airport near you... by siddesu · · Score: 0

      The roentgen is a machine that uses roentgen rays to take pictures inside of your body. It is used above to describe a truck with equipment that does something similar.

    7. Re:hmmmm coming soon to an airport near you... by maxwell+demon · · Score: 2

      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.
    8. Re:hmmmm coming soon to an airport near you... by Smallpond · · Score: 1

      Although the truck is disguised, you can tell they're there when they put the giant piece of film up on the other side of the house.

  4. Aluminum Foil by mbone · · Score: 4, Funny

    In the future, I guess snipers will have to carry a $ 5 roll of aluminum foil, to block the multimillion dollar real time radar.

    1. Re:Aluminum Foil by erice · · Score: 3, Insightful

      In the future, I guess snipers will have to carry a $ 5 roll of aluminum foil, to block the multimillion dollar real time radar.

      Which would shine conspicuously in the radar beam. That's where I'd shoot.

    2. Re:Aluminum Foil by mbone · · Score: 3, Insightful

      Crinkle it up.

    3. Re:Aluminum Foil by wagnerrp · · Score: 3, Interesting

      The wall already shines conspicuously in the radar beam. They had to put an analog filter into the receiving equipment to block out the massive return they get from the wall itself so it doesn't overpower their A/D. At most, you would be able to tell "there might be something of interest behind this wall... or maybe its just a sheet of metal...".

    4. Re:Aluminum Foil by vaene · · Score: 1

      Right cause the sniper wouldn't put up any false positives would he, for you to give away your position first?

    5. Re:Aluminum Foil by Sulphur · · Score: 1

      In the future, I guess snipers will have to carry a $ 5 roll of aluminum foil, to block the multimillion dollar real time radar.

      Which would shine conspicuously in the radar beam. That's where I'd shoot.

      Its a trailer park, or the enemy would make everyone put foil on their windows.

    6. Re:Aluminum Foil by DNS-and-BIND · · Score: 1

      Yes, because a roll of aluminum foil can easily wallpaper an entire room, and aluminum foil is readily available in war zones. Moreover, snipers will carry enough foil to wallpaper the multiple rooms they displace to after shooting once. Whatta dumbass remark.

      --
      Shutting down free speech with violence isn't fighting fascism. It IS fascism!
    7. Re:Aluminum Foil by dintech · · Score: 1

      Luckily the xenomorph don't have aluminum foil, so this motion tracker is still good.

    8. Re:Aluminum Foil by L4t3r4lu5 · · Score: 1

      In the future, I guess snipers will have to carry a $ 5 roll of aluminum foil, to block the multimillion dollar real time radar.

      Which would shine conspicuously in the radar beam. That's where I'd shoot.

      Ok, so $5 foil and $3 blu-tak, so you can put it on the wall you're hiding behind.

      --
      Finally had enough. Come see us over at https://soylentnews.org/
    9. Re:Aluminum Foil by Wild+Wizard · · Score: 1

      A fridge is all you need

      http://www.youtube.com/watch?v=YNJ4c0B-s1Y

      Just before the 8 minute mark

    10. Re:Aluminum Foil by xmorg · · Score: 1

      True dat.

    11. Re:Aluminum Foil by Smallpond · · Score: 3, Insightful

      Or maybe the $10 microwave detector so when they get an alarm they start shooting at the truckload of equipment outside their house.

    12. Re:Aluminum Foil by oodaloop · · Score: 1

      Yes, because a roll of aluminum foil can easily wallpaper an entire room

      As other posters pointed out, you don't need to do the whole room.

      aluminum foil is readily available in war zones

      Neither are fertilizer, aluminum powder, potassium chlorate, and other elements used to make IEDs in Afghanistan. They ship it in. Ammonium Nitrate has gone from about $7/40 lbs bag to over $100 in Afghanistan, and it's still being used. If it's an essential material that will save their lives or kill their enemies, they'll get it.

      Moreover, snipers will carry enough foil to wallpaper the multiple rooms they displace to after shooting once.

      If it's necessary, yes. You should see the extreme methods used to circumvent our equipment in Afghanistan. If it's what is necessary to do the job, yes they will do it.

      Whatta dumbass remark.

      Yours seems to be the dumbass remark. Do you have much experience in the military, other than playing FPS games?

      --
      Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
    13. Re:Aluminum Foil by mbone · · Score: 1

      I know a sniper who carries an umbrella (to block IR sensors). I think they can get their hands on aluminum foil. In fact, I think that they could get whatever they think they need.

    14. Re:Aluminum Foil by GameboyRMH · · Score: 1

      What if the whole wall has a layer of aluminum sheeting inside?

      --
      "When information is power, privacy is freedom" - Jah-Wren Ryel
    15. Re:Aluminum Foil by suomynonAyletamitlU · · Score: 1

      Shooting? Just hook it up to a bomb.

    16. Re:Aluminum Foil by Anonymous Coward · · Score: 0

      This is just an excuse to find pot farms and meth labs. (ie spy on U.S. citizens)

  5. Cool by phantomfive · · Score: 4, Interesting

    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."
    1. Re:Cool by azalin · · Score: 1

      I would assume that creating a 3 D Image from this technology is quite possible (though not trivial). In "field conditions"( the military is sure to love this gadget) it might not be necessary or feasible to have 3D. But if your planning for surveillance it might be worth the time to set up an array of these.
      Bad news for conspirationists though: Tinfoil hats will be very easy to spot and to be taken care of. Might want to invest in a radar detector though.

    2. Re:Cool by wagnerrp · · Score: 5, Informative

      It was a linear phased array. It literally can't tell up from down. If you wanted to make it sense in 3-D, you would have to make the array 2-D. Stack a couple of these units, throw in a couple more GPUs for processing, re-tweak the algorithm for an additional dimension, they could probably have a 3D model working in a couple weeks.

      The issue is that 3D really doesn't get you much. With the current 2D system, you can tell where someone is in a room, but its not like you can see any identifying features. All 3D would get you is a very rough estimate of height.

    3. Re:Cool by dotancohen · · Score: 1

      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.

      B) Somebody uses a Dvorak keyboard!

      --
      It is dangerous to be right when the government is wrong.
    4. Re:Cool by Anonymous Coward · · Score: 0

      It might be handy to know that the room that appears to be empty isn't actually filled with trained attack-tigers that are too short to show up on your normally chest-high scanning device.

    5. Re:Cool by wagnerrp · · Score: 1

      It's not chest high, because neither the transmitter nor receiver has much directionality in the vertical direction. The synthetic aperture only provides beam-forming in the horizontal direction. It scans the whole room, top to bottom, and returns a single data point for that column. It may even go through the floor and ceiling a pick up a slight return from someone on another level.

    6. Re:Cool by Anonymous Coward · · Score: 0

      Guess I should've looked into that before commenting.

      Thanks for the correction.

    7. Re:Cool by Anonymous Coward · · Score: 0

      Based on A: Not familiar with backscatter X-ray?

    8. Re:Cool by gumbi+west · · Score: 1

      Why would you do A, C if you used a Dvorak keyboard?

  6. Pivot That View by walkerp1 · · Score: 1

    I wonder if it might be useful to use a sine-wave deflector to pan this signal up and down for a front view. While having an X on a top down view would be useful, having a profile could be vastly better in many situations.

    1. Re:Pivot That View by wagnerrp · · Score: 4, Informative

      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.

    2. Re:Pivot That View by imakemusic · · Score: 1

      With a 20cm signal, you can't tell a human from an amorphous blob.

      Some people are amorphous blobs.

      --
      Brain surgery - it's not rocket science!
    3. Re:Pivot That View by dintech · · Score: 1

      you can't tell a human from an amorphous blob.

      There goes my hope for a highly sophisticated perv-o-cam. For now I'll have to make do with hanging out around the airport scanners.

  7. Seeing through the walls - ground combat by Trax3001BBS · · Score: 1

    Odd that it was sponsored by the Department of the Air Force,
    Or may-haps radar is their specialty.

  8. That ruins the use of by dredwerker · · Score: 1

    those guns that shoot around corners. http://www.gizmag.com/go/2576/

    --
    On a long enough timeline. The survival rate for everyone drops to zero. Chuck Palahniuk, Fight Club, 1996
    1. Re:That ruins the use of by SomePgmr · · Score: 1

      Meh, CornerShot is old. Like, 2003 old, and hasn't caught on anywhere that I've seen. Though I did see one used on a game show recently.

  9. Call of Duty by vaene · · Score: 3, Funny

    Who wants to play the special mission where you are the guy pushing around the cart with all the antennas sticking out of it?

    1. Re:Call of Duty by gd2shoe · · Score: 1

      Dude. Robot?

      --
      I won't join Slashcott. OTOH, If Beta goes live, I just won't be back until it's fixed. Sorry Dice.
    2. Re:Call of Duty by vaene · · Score: 0

      Dude. Who do you think we'll be fighting?

  10. Spaceballs- Barf: "Radar about to be jammed!" by lexsird · · Score: 1

    So, will my microwave oven jam this thing up? Cook lots of hot microwaved burritos and keep Big Brother from watching you? When will I get my glasses that let me see through clothes, see my own bones, etc? Remember those? They were on the opposite side of Sea Monkeys.

    Also, time to bring the radar detector inside so you know when to step out and unload some buckshot? Or just wire your radar detector into your homemade rocket and "nuke it" from a couple of blocks over?

    Stuff the walls with tinfoil? Or build your own radar wave emitter that fires back one OMFG radar wave ping at it, frying it?

    Lastly, make a "potato cannon" that shoots jars of Strawberry Jam and blast the array with it?

    Countermeasures, we got them.

    --
    Take the Red Pill.
    1. Re:Spaceballs- Barf: "Radar about to be jammed!" by Anonymous Coward · · Score: 0

      So, will my microwave oven jam this thing up?

      No.

      This type of radar is Ultra Wide Band, it is impervious to narrow-band interference from sources such as 2.4GHz microwave oven magnetron.

    2. Re:Spaceballs- Barf: "Radar about to be jammed!" by cavePrisoner · · Score: 1

      The tinfoil is less of a countermeasure and more of a billboard. It would work only if you are willing to line the walls of every building in the area. Otherwise, we'll assume the bad guys are in the buildings lined with foil.

      Personally, I think this has only limited use on a battlefield until the definition gets a lot better. You don't shoot just anything that moves on a battlefield (at least not recently). You don't shoot unless you're pretty sure you're about to get shot/blown up yourself. This can tell us somebody is in a building, but we'll still have to clear it the old fashioned way because we won't be able to tell if its military or civilian inside. So not really the greatest help in the world. With better definition, we might be able to identify weapons in the building which in turn could lead to justification to attack the building without entering it first. Obviously that would be a lot safer.

  11. Radiation by qxcv · · Score: 1

    In a story a few days back about GPS jamming somebody mentioned how ineffective it was because of the use of radiation-guided missiles - could soldiers operating this giant radar end up in HARM's way (geddit?), and wouldn't it be possible to create a simple radiation detector that could show when such a radar is operating nearby?

    --
    "The most dangerous enemy of a better solution is an existing codebase that is just good enough." -- Eric S. Raymond
    1. Re:Radiation by nedlohs · · Score: 1

      Sure, but you are dealing with urban combat in which HARMs aren't really a concern. When you jam GPS you would usually be trying to stop missiles and bombers from getting you - an environment in which HARMs are certainly going to be involved.

      If the other side using such missiles against your infantry you are not fighting house to house and room to room anyway. You are still levelling them from the air.

  12. Prior Art by milbournosphere · · Score: 1

    Meh, Counter Strike bots have been doing this for years.

    1. Re:Prior Art by Dark+Lord+of+Ohio · · Score: 1

      thats why CS sucks a lot! Real men play Halo! :)

  13. solid wals, as compared to what other walls? by mestar · · Score: 1

    "what's going on behind solid walls."

    Of course, what is going on behind liquid walls will remain a mystery.

    "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"

    Of course, the main problem in achieving the "speed, resolution and range" is that you lose 99% of the signal, twice.

    In other words, signal loss is not the main problem, except that it is.

    What idiot wrote that? Manipulative idiot, that's who.

    1. Re:solid wals, as compared to what other walls? by Anonymous Coward · · Score: 0

      If most of the signal was lost, it means it either bounced, or was absorbed, otherwise it travels in a straight line.

      Presume equally, a patriot who is smart enough can actually pre-plan a method to defend the US Constitution against this fourth amendment violation using electronic tools connected to a booby-trap targeting such coup would be right within their US Constitutional rights.

      swr meter and bamboo spikes?
      spectrum analyzer and knockout gas?
      freq counter and a bank of SCR's?
      A lightbulb comes on and people come out and sweep for enemies.

      How it's suddenly popular to run a fucking transmitter array targeting the front of someone's house, and yet people who already complain about covert electronic harassment are laughed off. That's a setup for some really bad fail, with no true redress being anything less than mortal.

      Want to make an enemy who might try to kill you later on? Point this shit at someone who don't deserve it.

      A platform in space, send a microwave beam down on your ass continuously until you are gone.
      Real simple, a solar power source, a crystal in a pure vacuum, and an directional antenna and it's good night bitches.
      Roast in Peaces, Hell on Earth

      Fuck all you oath breaking pieces of shit, the only thing you got left is to kill your own citizens, but I ain't scared of death anymore bitches.

  14. Czech republic had it earlier by Anonymous Coward · · Score: 1

    Hi, I saw something like that from Czech company RETIA.
    Or what about camero-tech and their Xaver 800?
    It seems to have better resolution.

    1. Re:Czech republic had it earlier by tibit · · Score: 1

      The ReTWIS has lower resolution than this project, it'd seem, and it's similarly a 1D antenna system only to provide a cross-sectional view.

      The Xaver 800 seems to have comparable resolution and 2D antenna to provide 3D imaging, but is using much higher-tech approach. TFA is a system you can easily homebrew if you have RF experience, the Xaver 800 -- not so much.

      --
      A successful API design takes a mixture of software design and pedagogy.
  15. "See" ? by Anonymous Coward · · Score: 0

    If with my eyes this is how I saw I would have a serious disability.

  16. Is it really that useful? by jklovanc · · Score: 2

    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?

    1. Re:Is it really that useful? by satuon · · Score: 1

      Even if they weren't armed, you could always place a pistol in their hands post-factum.

    2. Re:Is it really that useful? by Tuan121 · · Score: 1

      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.

      Yeah, look at the size of computers 40 years ago. We should have stopped the research then and blindly criticized because they were so big and not practical.

      Give it a rest, yes it's big. For now.

    3. Re:Is it really that useful? by jklovanc · · Score: 1

      I was talking about the size of the phased array antenna. The multiple antennas need to be separated by a certain distance so they do not interfere with each other and need to be a certain size so they can gather enough radiation. That's the physics of radar and no research is going to change that. Phased array radar is not new technology; it came out on the Ticonderoga class cruiser in 1978. One would think that they would have made the array as small as possible in the first place

    4. Re:Is it really that useful? by Anonymous Coward · · Score: 0

      It's a prototype, it can probably be made smaller with alternate antenna design. E.g. go for half-wavelength elements, which is less efficient but can in principle be compensated for by increased transmission power.

    5. Re:Is it really that useful? by Anonymous Coward · · Score: 0

      Wouldn't it be easier for small robot to crawl up the wall, drill a smal hole and insert a mirco camera?

    6. Re:Is it really that useful? by gknoy · · Score: 1

      It seems like something that could be extremely useful for scouting a room in a hostage rescue situation: you know the bad guys are in this room, but you want more info on where. Of course, they could probably use a fiber optic camera for that in most cases.

    7. Re:Is it really that useful? by jklovanc · · Score: 1

      The only issue with a fibre optic camera is that it needs a hole to look through. It is quite possible that the drilling through the concrete wall could be heard.

  17. The real question by lucm · · Score: 1

    Does this system run on "Windows"?

    --
    lucm, indeed.
    1. Re:The real question by Anonymous Coward · · Score: 0

      No, the real question is: Can we look with this through the blonde bomb shells clothes...

    2. Re:The real question by lucm · · Score: 1

      No, the real question is: Can we look with this through the blonde bomb shells clothes...

      That would be convenient to spot girls with a tramp stamp before it's too late (one way or the other).

      --
      lucm, indeed.
    3. Re:The real question by almitchell · · Score: 1

      The drivers for the transmitters aren't compatible with 64-bit.

      --
      Baseless self confidence kills more people each year than bathtubs.
  18. youtube by Dark+Lord+of+Ohio · · Score: 1

    soon we will be "flooded" with home-made pr0n movies on youtube made by some pranksters. I think it's time to buy seethruwallstube.com domain.

  19. Similar device by Cambridge Consultants by fishicist · · Score: 1

    Cambridge Consultants demonstrated something similar a few years ago. It's called Sprint and there's a great big picture of it here.

    1. Re:Similar device by Cambridge Consultants by Anonymous Coward · · Score: 0

      There are others as well.
      Czech company Retia makes similiar device called RetWiz (page is in English)

    2. Re:Similar device by Cambridge Consultants by jklovanc · · Score: 1

      Sprint is for seeing inside walls not through them in real time.

    3. Re:Similar device by Cambridge Consultants by fishicist · · Score: 1

      Oh. So it is. Nevermind. :)

  20. Soliton Radar from Metal Gear Solid! by Anonymous Coward · · Score: 0

    http://metalgear.wikia.com/wiki/Soliton_Radar - all they need to do is to develop some algorithms to deduce which direction the person is facing and overlay a cone for their field of vision!

  21. Bazookas by vm146j2 · · Score: 1

    Also allow you to see through walls.

    Just sayin'

    --
    "Lost time is not found again."
  22. Fourth Amendment vs DHS by Anonymous Coward · · Score: 2, Insightful

    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.

    1. Re:Fourth Amendment vs DHS by Curunir_wolf · · Score: 1

      Thank you, sir. You're encouraging me to join the "OWS" groups and help them avoid being co-opted.

      Mod. Parent. UP.

      --
      "Somebody has to do something. It's just incredibly pathetic it has to be us."
      --- Jerry Garcia
    2. Re:Fourth Amendment vs DHS by tibit · · Score: 1

      While some of your objections against such technology's possible uses are understandable, the technology is not to blame. What we already have: miniature cameras and insane U.S. building standards will let anyone spy on anyone else anyway, right now, with much simpler tech.

      For non-U.S. dwellers: a typical recent U.S. single-family residential building's wall consists of, going inside out: paint, drywall, plastic vapor block, vertical wood studs with fiberglass insulation between them, foam board "sheeting", home wrap membrane, plastic siding. Siding is in horizontal sections and is easy to snap off and snap back on. To spy on someone:
      1. pull up a piece of siding,
      2. use fingers/knife to go through home wrap and board,
      3. push fiberglass insulation aside, scrape some drywall from outside to make it thinner,
      4. drill a small hole, place a wireless camera with power source against the recess you've made in drywall
      5. put insulation back around the camera to hold it in place
      6. snap siding back in

      With experience, I imagine it'd be a one minute job, and if the hole in the drywall is strategically located, no one will notice. Who the heck needs advanced through-the-concrete radar...

      Most homes will have simple variations upon this theme: aluminum siding instead of vinyl on older homes, lack of insulation in the wall cavities, sometimes the exterior sheeting is OSB (oriented strand board) -- you can punch a hole in it with a screwdriver :)

      --
      A successful API design takes a mixture of software design and pedagogy.
    3. Re:Fourth Amendment vs DHS by cavreader · · Score: 1

      The 2nd Amendment already provides the means to confront most of the BS in your "Wah Wah Wah..." rant. The idea of technology being unconstitutional is just as stupid as those claiming opensource software is a human right. Firearm technology developed 200+ years ago that can infringe on your rights just as effectively as technology capable of looking through walls. It's not the technology it's the people using the technology. Your argument boils down to stopping all technological advances just because someone might use it for a bad reason.

    4. Re:Fourth Amendment vs DHS by gknoy · · Score: 1

      the technology is not to blame

      So true.

      Unconstitutional searches can be done with nothing more than one's eyes, or by breaking in a door and searching using a sledgehammer and searching. It's not the technology that makes a search bad, it's the people that are doing it and their willingness to disregard the fourth amendment.

    5. Re:Fourth Amendment vs DHS by dkleinsc · · Score: 1

      This is the path to darkness, death, destruction and marital law.

      As the son of a lawyer who handled a lot of divorce work, I have to say that was one of the funniest typos I've encountered in a long time.

      You're mostly right about the rest of your post though. The thing I want to point out, though, is that many of the civilian population are justifiably afraid that if they do something about what's going on, they'll lose any chance of working, which means they'll (soon, once the 2012 election is done) lose their ability to feed, clothe, and house themselves and their kids. Or they just might get beaten by the cops, arrested and tried for assaulting the cops' knee with their groin, and thrown into prison where they get repeatedly raped and beaten. Or they might get taken in for questioning as a material witness and thrown into the equivalent of Gitmo for a decade. Or they might be put on president Obama's hit list and taken out with cruise missiles. And if it came down to a full-scale military conflict between the US government and its citizens, the government wins hands down, because at this point you're talking about a situation where international stigma doesn't matter so they'll be quite happy to use their WMDs.

      --
      I am officially gone from /. Long live http://www.soylentnews.com/
  23. Cheaper solution. by thoughtspace · · Score: 1

    What about standing on the other side of the wall?

  24. Military by Curunir_wolf · · Score: 1

    But it has powerful implications for military operations, especially "urban combat situations,"

    Oh, yes, that's where it will be used. No way they would EVER use it against their own people.

    --
    "Somebody has to do something. It's just incredibly pathetic it has to be us."
    --- Jerry Garcia
    1. Re:Military by jklovanc · · Score: 1

      Like IR cameras, it would soon be banned from doing illegal searches.

    2. Re:Military by Curunir_wolf · · Score: 1

      Like IR cameras, it would soon be banned from doing illegal searches.

      Those aren't banned at all. They just can't use the results of car-based cameras as evidence in court. They still use the ones in helicopters to conduct raids, and I'm sure they use them in plenty of other circumstances, too.

      Of course, all they need these days is a grant from DHS and a claim that they are looking for "terrorists", and they can do whatever they want. No court even needed, once they ship you off to Gitmo.

      --
      "Somebody has to do something. It's just incredibly pathetic it has to be us."
      --- Jerry Garcia
    3. Re:Military by Curunir_wolf · · Score: 1

      Like IR cameras, it would soon be banned from doing illegal searches.

      Thought I'd follow up with this little tidbit, from a story about the SCOTUS case you're referring to:

      Detective Larry Wilson of the Plano, Texas, police force, said it has been common for police to use thermal imaging on houses without first obtaining a warrant, and that will change.

      But he says the police in his department and others he's trained around the country have been instructed not to use the devices without having first obtained probable cause through other means. So he says the ruling should not greatly affect current police use of infrared cameras on homes.

      "Whenever we're doing an indoor grow operation investigation we've already established the necessary probable cause prior to doing the thermal imaging," said Wilson. "Now the only step that's going to be added is to get an affidavit and get a judge to do that and issue a warrant."

      So, far from being banned, they're using them as much as they always have.

      --
      "Somebody has to do something. It's just incredibly pathetic it has to be us."
      --- Jerry Garcia
    4. Re:Military by jklovanc · · Score: 1

      There is a huge difference between an illegal warrantless search, which I was referring to, and a search sanctioned by a warrant. With a warrant the police have a judge's permission to look into a building. Whether it is done by radar, IR or eyeballs makes no difference. So no, the police are not going to be driving down the street scanning random people in their houses.

      As a ERT tool this is a good one. It could be used before a search warrant is executed to locate all people in the house and possibly decrease the need to go on hard and fast. This may save lives; both on the police side and the civilian side. When executing a warrant all reasonable tools should be used.

    5. Re:Military by Curunir_wolf · · Score: 2

      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
    6. Re:Military by jklovanc · · Score: 1

      Interesting how you neglect to mention the deaths of police and innocent civilians caused by the purveyors of recreational drugs. Some of the deaths of innocent civilians occur when two purveyors of recreational drugs fight over the same territory. There are many documented cases of drug gangs having and carrying automatic weapons and assault rifles. So when the police have to deal with these gangs that do so using heavily armed, highly trained units. If you don't want to get shot when an SRU shows up then don't pull a gun. If you are an "innocent civilian" then don't frequent a drug gang's house that could be raided by an SRU at any time.

      I do not see how the use of radar expands the US anti-terrorism powers.

    7. Re:Military by Curunir_wolf · · Score: 2

      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
  25. What they don't tell you by Anonymous Coward · · Score: 0

    What they are not telling you here is that this is easy to foil. by adding material a simple metallic paint on bent cardboard, phase and direction information is dispersed to the point of being useless. Really this multi billion dollar radar project can be rendered useless with $29 worth of home depot products. I like how they talk about amplifiers are cheap. Spectrally pure LNAs are not cheap, are very fragile and are very susceptible to background noise. The gain that would be needed to receive this kind of reflection puts the signal way below the noise floor. So now you need millions of dollars worth of noise cancellation equipment to get the noise floor low enough to be able to pick out the signal.

    I hope the Defense department is not stupid enough to put any money into this full cocked idea!

    1. Re:What they don't tell you by mschiller · · Score: 4, Informative

      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...

    2. Re:What they don't tell you by tibit · · Score: 1

      This is not a multi-billion dollar project. With a bit of resourcefullness, you could do it yourself for under $2k in hardware, assuming you've got a good PC and a decently instrumented electronics workbench. There's no magic "millions of dollars worth of noise cancellation equipment" -- it exists in silly movies only. Either you are above or below noise floor, and even if you're below you can employ averaging to trade off bandwidth (in the sense of frame rate) for SNR improvement. Heck, they do a lot multiplexing and use a really simple data acquisition setup. If they'd get each antenna to have its own oscillator and radiate at a different frequency, they could run all the antennas at the same time, improving their SNR by quite a bit because they'd have more data to average from.

      --
      A successful API design takes a mixture of software design and pedagogy.
    3. Re:What they don't tell you by tibit · · Score: 1

      I think if they had a wider bandwidth ADC they could get rid of the analog Doppler filter. Eventually the oversampling in the ADC would give them back the dynamic range they need. They used about as basic of an A/D card as it gets. The BOM is way less than $200k I'm sure. The boards for the antennas probably aren't cheap due to their size, and I don't know if they are FR-4 or Rogers. They'd probably cost $2k or so on a 1 week turnaround, probably less. The RF components and cables can be scavenged off eBay if you have time, or bought from mini-circuits and similar suppliers, the latter will run another $5k tops I'd think. The A/D board is $1.2k. Mechanicals will run another $2k or so. So in a pinch you can do it for $10k in hardware less PC. If you have time to do your own board layout and circuit design, and have time to use long leadtime PCB suppliers, you can get an even better signal chain for way less money -- I think $2k of electronics per system for a run of 10 is not unimaginable. You could put the RF signal chain on a PC board and use cheaper components than having to wire everything up from enclosed modules, as they perhaps did.

      They use very little bandwidth between ADC/DAC and PC, this could be easily running via Ethernet. With a proper choice of CPU they wouldn't even need an FPGA. I think that their current design's front-end digital logic would fit entirely on a Parallax Propeller attached to ADC, DAC and switches, with external Ethernet interface attached to it to stream the raw data to the PC. The Prop is too slow to do the DSP of course, but for sequencing, waveform playback and acquisition it'd work just fine. I think that a single board with ADC, CPU, Ethernet, and all of the RF signal chain could be had for $1k total in qty 1, and none of it would be very exotic at all - not a single BGA to be soldered, I'd think.

      They had to trade off time for money to get this done without wasting a couple years. For proofs-of-concept it's the way to go. The design leaves a lot of room for improvement, and that's what I really like about it. If one only had enough time to play with all that! The article is detailed enough that with consulting some of the references you could replicate the whole system without too much sweat. I really like their approach to signal processing on the PC, controlling the show from Python. Very slick.

      --
      A successful API design takes a mixture of software design and pedagogy.
  26. I can't wait by TrixX · · Score: 1

    Until this stuff is installed on the Google Street View cars!

  27. Extension of an earlier story by stewbee · · Score: 2

    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.

    1. Re:Extension of an earlier story by smellsofbikes · · Score: 1

      Since you seem to know something about it, maybe you could answer this: why is this suddenly such a big deal? I thought the original article was a big deal because he'd made synthetic aperture radar out of stuff he picked up on ebay -- it was a really amazing DIY hack, in other words. But militaries have had SAR for decades, right? So how is what he's doing different than what's been available for many years? Obviously it is, because this is making news all over the place, but I feel like I'm missing some important part of the research/development.

      --
      Nostalgia's not what it used to be.
    2. Re:Extension of an earlier story by stewbee · · Score: 2

      While I somewhat agree with you, I haven't followed it too closely. However, I believe that Greg mentions what some limitations are of SAR and that would be the real time processing to make it viable for field use. I think how things were done before was that you had several radar images taken by a single radar that had physically been moved at some small increment apart. Now here, he has several antennas so that all he as to do is electronically switch between antennas in his array to capture the images. This would reduce the time for the total image capture while still getting the physical separation required to be able to create a SAR image.

      Computing has also improved to a point where an off site computer is no longer required to compute the resultant image which I think was/is done with satellite images.

      And I think I read this in the attached article that was there is still some work to be done on the resolution of the images from this application. I could see how this could be difficult since there is still some finite delay time between image captures from the individual antennas. I would imagine this would cause the object of interest to be more disperse in the resultant image. Usually SAR images are done on static objects, so I myself don't know what the impact would be on the added difficulty of a moving target on a SAR image. I think I read that they were using a difference algorithm between images to detect the motion of the object.

      Finally, I think that Greg may be down playing the difficulty of 'seeing' through the wall. He uses percent to show how much attenuation the transmitted and reflected signal experiences, but being an RF guy myself, am used to dB. It sounded like it would be about 30 dB of attenuation each direction through the wall. That doesn't even account for free space path loss. To go through the wall twice, you lose 60 dB of transmit power. Additionally, not all object will reflect the power completely. Assume maybe you lose another 20 dB due to imperfect reflection (admittedly a guess) then we are now up to 80 dB of the initial power lost that was transmitted to be able to make a reliable return from the object that is an imperfect RF scatterer. Looking at his rig, it didn't look like he was using too large of a transmitter, so that would put a lot of work on the receiver to detect these signals. He is correct when saying though that he can just use amplifiers to get the signal to a usable level, but at the same time you would like to have a larger SNR on the receive signal since it would make each radar snapshot clearer.

      That is probably the extent of my knowledge on SAR imaging, and I am no expert. I just know enough to be dangerous :)

    3. Re:Extension of an earlier story by Anonymous Coward · · Score: 0

      Oh, and I am not a groupie. I happen to actually know Greg.

      And he can see what you and your gf get up to behind concrete walls!

  28. Seen in science fiction by mattr · · Score: 1

    There was a similar device in a sci-fi novel I read some decades ago, I forget the name but it might possibly have been California Dreamtime. Anyway, an assassin (bad guy) equipped with super advanced milspec tools is stalking someone and has a sonar device on his belt and contact lens displays. I wonder if sonar, or perhaps a laser scanner (as typically available for robots, but at microwave or terahertz frequencies) wouldn't be better than radar.

  29. Will it work for all walls? by 140Mandak262Jamuna · · Score: 1
    The best I could make out from the description was that it is basically radar. But the echos have small difference in frequency compared to the original radiated signal. They use a band-pass filter, must be a very good one, to filter out the echo from the wall, and then amplify the faint echos from objects behind the wall. The array of radar would each get a "2D" view, and it is synthesized into a three D image using image processing. Sort of like X-Ray tomography in the image reconstruction process.

    The whole scheme depends on the wall reflecting in a slightly altered frequency uniformly. If you are not able to subtract the echo from the wall, you can't amplify the fainter echos from beyond the wall. Systems to thwart it would be to "roughen" the wall, interior or exterior to make the wall echo difficult to subtract. Other ways would be to have very bright echo returns that mess up and saturate the amplification of the faint echos. Also the standard stealth technologies like faceted body producing vastly different images for different elements of the array to thwart the image processing and synthesizing the scene behind the wall.

    I think the resolution is poor, and is useful for hostage, military situations only. Dont have to worry about your creepy peeping tom neighbor buying this off the shelf to ogle your bath/bedroom.

    --
    sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
    1. Re:Will it work for all walls? by tibit · · Score: 1

      There are no frequency differences from the echos from stationary objects. They use beamforming/SAR techniques to get a stationary antenna to form a 2D image in downrange/crossrange coordinates (far/near vs sideways). There's no imaging along the top-bottom direction, although that's not a big issue: all they'd need is to replicate their linear antenna into a 2D antenna. The echo from the wall is still there, but they simply subtract a reference radar image from current image. If you stand very still, the radar will be blind to you :) The wall echo is not useless: it lets you use the radar for mapping, where you need static references like walls to stitch the images together.

      --
      A successful API design takes a mixture of software design and pedagogy.
    2. Re:Will it work for all walls? by tibit · · Score: 1

      Hmm, I've re-read the article and it does seem like they use a filter to get rid of some of the wall echoes. They say it's their way of doing range gate, and I only imagine it's because the transmitted pulse is frequency-chirped. The earlier reflections will have different frequency than the later ones, so they essentially shift a time domain problem into frequency domain by sending out a time-dependent frequency signal.

      --
      A successful API design takes a mixture of software design and pedagogy.
  30. privacy issues by blackair · · Score: 1

    How long till something is like this available to law enforcement . They have already gotten away with putting gps trackers on people's car in their drive ways with no judicial over-site. The privacy and legal ramifications are going to be immense. Stewbee pointed out that the majority of the plans are on developers blog, since we got camera phones people don't hesitate to violate each others privacy, imagine what will happen with this.

  31. Star Wars FTW by tibit · · Score: 1

    See page 554 in TFA. They image a guy holding a metal rod. The name of the output file in the screenshot? StarwarsKid. Yay!

    --
    A successful API design takes a mixture of software design and pedagogy.
  32. Screw the military applications... by Anonymous Coward · · Score: 0

    I needed this when I was pulling CAT-6 through the walls of mom's base... er, I mean my house!

  33. Why a military application? by Anonymous Coward · · Score: 0

    Of course I didn't RTFA, but my first reaction was that they could have real value in disaster scenarios - think earthquakes - rather than most of the commenters who seem focused on military or police value. Seems to me like knowing whether there is somebody under this pile of rubble that we need to help is a much more useful application of the technology.

  34. Mount it on a helicopter! by inhuman_4 · · Score: 1

    I don't know why most people assume that this will be attached to a truck, or moved my hand. If I were the military first thing I would want to use it for is helicopter surveillance. You would have to make it more powerful to work at reasonable elevation, and would probably want to widen the field of view. Not easy tasks I'm sure.

    But suppose that you could fly around in a helicopter higher and faster than "likely to get shot down by rifle fire" speed/range or at night. You could scan large swaths of houses and watch for movement inside them. It could provide a good estimate of troop numbers and concentrations.

    I could also see it used to hostage rescue. Dress the helicopter up like a TV crew and scan the building. You could figure out (with some guess work) the number of bad guys, number of hostages, and where everything is located.

    I'm pretty confident that this technology is a CIA/DIA wet dream.

  35. MIT invents real life Wallhack by Anonymous Coward · · Score: 0

    Cheaters.

    lol

  36. isn't this what windows do? by k6mfw · · Score: 1

    These devices have been around for thousands of years...

    --
    mfwright@batnet.com
  37. *bzzzt* THUMP by Fned · · Score: 1

    "Hey, it looks like there's a guy with a pacemaker on the other side of this wall."

    "Shit, really? That thing can see that kind of detail?!"

    "No, not really."

    "Well, then how can you tell he has a pacemaker?"

    "He just fell down and died."

  38. Motion Scanner by Fned · · Score: 1

    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.

    Instead of Aliens or X-COM you're thinking Zelda and Harry Potter?!

    1. Re:Motion Scanner by phantomfive · · Score: 1

      lol I never saw Alien and never played X-Com. Sorry, mate.

      --
      "First they came for the slanderers and i said nothing."