back to article Through-wall tracking of humans using Wi-Fi: Now more accurate, low power

The MIT boffins that earlier this year demonstrated the ability to “see through walls” using Wi-Fi has now unveiled a more accurate version, WiTrack, that can locate a person in three dimensions, within 10-20 cm, through walls and obstructions. Unlike the earlier Wi-Vi project, the new work by Dina Katabi, Fadel Adib and their …


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  1. Eddy Ito Silver badge
    Big Brother

    So I assume this tinfoil hat just gives me a greater Wi-Radar cross section. Clearly once the NSA starts deploying this widely I'm going to need a tinfoil yurt.

    1. phuzz Silver badge
      Black Helicopters

      Actually, there was some research from MIT a few years ago that shwoed that a tinfoil hat actually AMPLIFIED some wavelengths. The odd thing is, both of the amplified parts of the spectrum are reserved for military use...

  2. William Boyle

    @Eddy Ito: Yeah, the NSA and CIA (and other national TLA's) will have a field day with this! Now, just where did I put my Faraday underwear?

    1. Eclectic Man
      Big Brother

      All we need to do is paper the walls, ceilings and floors with aluminium foil ... bit of a bummer for TV, radio and cellphone reception though.

  3. Martin Budden Bronze badge

    Is that a computer-generated voice with a German accent?

    1. Fair Dinkum

      Not german. And not computer generated, either, as far as I can tell.

      The only really funny sounding character is "R", my guess woud be indian. (Curry, not bows and arrows)

  4. Wzrd1

    In other words

    MIT caught up to the UK by re-inventing radar.

    1. Christian Berger Silver badge

      Re: In other words

      Yes, and they even put it to the worst practical use, rough gesture control. I mean I could understand is if it was good enough to offer a "virtual keyboard", then you could use it as an input device.

    2. MrXavia

      Re: In other words

      Yup, fancy radar, but still radar...

      That is not to say the usage is not impressive, the software to detect body parts.. quite impressive

      I wonder if this could be accurate enough to do full body tracking? that would be brilliant.

  5. F111F

    End of the Couch Potato?

    So, if an entrepreneur were smart, he could build a reproduction of a walk-through of DOOM or some other first person shooter type game, put projection displays on the various walls linked to the game and track/feedback the gamer with this tracking system?

    If he then linked it with other walk-throughs, you could have multiple teams duking it out...World of Warcraft in 3-D?

  6. JCitizen


    Now the cops/GWOT soldiers can see the enemy standing in the room and shoot through the wall with utmost accuracy. Then don't need a set of eyeballs in the room to prevent collateral damage!

    1. Mr C

      Re: Yep!

      We've done work using very similar concepts about 15 years ago, instead of wifi using sound.

      Although the video doesn't mention it i know that this will only work if the receivers have been positioned with accuracy and exact position in relation to each other, with a decent calibration cycle before before you can get any sort of usable accuracy.

      Meaning that this technology will only be useful in predetermined areas / setups, in rooms where technicians had time to work and set it up correctly.

      NCIS-style-walk-in-the-room-press-a-button-and-see-through-walls isn't going to happen from this any time soon.

      1. Dr_Cynic

        Re: Yep!

        And lots of modern buildings use foil coated plasterboard in their construction , which will also somewhat restrict the ability to 'see' through walls.

  7. Pete 2

    Big is better

    > military are high powered, heavy, and demanded large antenna arrays

    Well, yes.

    Because military radar isn't used to detect whether the general in the next room has fallen of his/her's perch. The problem with RADAR is that it suffers from an inverse squared, SQUARED law. I.e. 1 / (r ** 4) power/distance relationship. The signal going out from the transmitter is the normal 1/r^2 degradation with distance to the target and the signal reflected off the target (assuming it's "playing the game" by not being stealthy) comes back with the same power::distance ratio. Hence the need for massive amounts of power, huge receiving (and transmitting) antennae and therefore large installations.

    I'm sure that given their expertise in the area, the military are more than capable of making a bitsy little version - and could / would / probably-have if there was a requirement ... say from the clandestine services.

    Now where did I put that foil-backed wallpaper?

    1. Fair Dinkum

      Re: Big is better

      Wouldn't that be 1/((2r)**2 degradation, and hence 1/(4*r**2)? My maths a bit rusty, so please correct me if I am wrong.

      1. Pete 2

        Re: Big is better

        To get twice the range (for the same receiver sensitivity) you need 16 times as much power. Strictly speaking: EIRP

        16 = 2^4

    2. cortland

      Re: Big is better

      And the radar cross section of the target is usually small enough you don't get back much to begin with.

  8. auburnman
    Black Helicopters

    So THIS is what Google were up to in the Maps/WiFi slurp.

  9. Anonymous Coward
    Anonymous Coward


    Am I the only one here who lives in a semi-detached house? Ooooh, I don't want the neighbours seeing what we get up to...

  10. Anonymous Coward
    Anonymous Coward

    Tenuous connection to WiFi though

    The "5GHz" WiFi band seems to span about 5.2~5.8GHz depending on geography.

    And presumably this radar doesn't use any WiFi protocols.

    So why "WiFi" in the headline? It's just a (admittedly cool) low-GHz short-range/wideband radar.


    1. Old Handle

      Re: Tenuous connection to WiFi though

      Yeah, I first thought this was going to be a system for passively detecting people using existing wi-fi networks as a source of "illumination". That would have been a more impressive achievement.

  11. Why Not?

    single person or multi player?

    They seemed to avoid talking about sensing multiple people. Will the cat jumping about turn the lights out?

    Kinnect does all of this apart from going through "walls" or as in the demo stud partitions.

  12. Robert 22

    Big Brother will be happy! Now, even if you are outside the Telescreen field of view, we will still be able to monitor your traitorous behavior!

  13. joanbee

    Between this and sub-millimeter handheld radar...

    I expect an upsurge in the use of metallic patterned wall-coverings. You didn't have to ground them back in the seventies, though.

  14. Mark York 3 Silver badge

    Targets gamers, elderly, and the utterly slothful

    & the first thing that came to my mind was Blipverts.

  15. i like crisps


    ...This sounds similar to to the "BAT-VISION" in Arkham City....wonder if people they're watching through the walls show up as "Skeletons" as well? That would be WICKED!!

  16. John Robson Silver badge

    Am I the only person thinking....

    Disaster zones, avalanch le recovery etc..

    1. i like crisps
      Big Brother

      Re: Am I the only person thinking....

      At last, the "Killer App" for Goggle Glass?

  17. cortland

    Through the wall -- not new

    Ultra-broadband through-wall radar is already in use. The FCC restricts its use in the USA to law enforcement and emergency services. See for example

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