Free Republic
Browse · Search
General/Chat
Topics · Post Article

Skip to comments.

New system uses low-power Wi-Fi signal to track moving humans even behind walls
MIT.edu ^ | June 28, 2013

Posted on 06/29/2013 5:17:05 PM PDT by BenLurkin

The system, called “Wi-Vi,” is based on a concept similar to radar and sonar imaging. But in contrast to radar and sonar, it transmits a low-power Wi-Fi signal and uses its reflections to track moving humans. It can do so even if the humans are in closed rooms or hiding behind a wall.

As a Wi-Fi signal is transmitted at a wall, a portion of the signal penetrates through it, reflecting off any humans on the other side. However, only a tiny fraction of the signal makes it through to the other room, with the rest being reflected by the wall, or by other objects. “So we had to come up with a technology that could cancel out all these other reflections, and keep only those from the moving human body,” Katabi says.

Motion detector

To do this, the system uses two transmit antennas and a single receiver. The two antennas transmit almost identical signals, except that the signal from the second antenna is the inverse of the first. As a result, the two signals interfere with each other in such a way as to cancel each other out. Since any static objects that the signals hit — including the wall — create identical reflections, they too are cancelled out by this nulling effect.

(Excerpt) Read more at web.mit.edu ...


TOPICS: Science
KEYWORDS:

1 posted on 06/29/2013 5:17:05 PM PDT by BenLurkin
[ Post Reply | Private Reply | View Replies]

To: BenLurkin

I wonder if this will be just as illegal as using FLEER to look for people growing pot in homes?


2 posted on 06/29/2013 5:22:58 PM PDT by Mastador1 (I'll take a bad dog over a good politician any day!)
[ Post Reply | Private Reply | To 1 | View Replies]

To: Mastador1

Doesn’t matter. A law for its use will be passed, signed and upheld by kangaroo courts.


3 posted on 06/29/2013 5:24:09 PM PDT by BenLurkin (This is not a statement of fact. It is either opinion or satire; or both)
[ Post Reply | Private Reply | To 2 | View Replies]

To: BenLurkin

or we’ll fimd out this article is really just new to the public, and that’s it’salready in use.


4 posted on 06/29/2013 5:26:18 PM PDT by Secret Agent Man (Gone Galt; Not averse to Going Bronson.)
[ Post Reply | Private Reply | To 3 | View Replies]

To: BenLurkin

Well the courts ruled that police who raided a pot grower on the evidence of the heat signature picked up by FLEER through the case out for illegal violation of fourth amendment rights.


5 posted on 06/29/2013 5:30:32 PM PDT by Mastador1 (I'll take a bad dog over a good politician any day!)
[ Post Reply | Private Reply | To 3 | View Replies]

To: Mastador1

FLIR. Fleer makes bubble gum.

This concept is valid, but at 2 or 5 ghz wifi frequencies the resolution will be poor compared with UWB, which has been used for thru-wall imaging for several years.


6 posted on 06/29/2013 5:45:47 PM PDT by bigbob
[ Post Reply | Private Reply | To 2 | View Replies]

To: BenLurkin

I assume a sniper could ‘see’ his target through the wall then blast him with a 50 caliber.

If King George had this kind of technology and the Patriots didn’t, we’d still be part of England.


7 posted on 06/29/2013 5:47:45 PM PDT by VerySadAmerican (If you vote for evil because you can't see evil, you ARE evil!)
[ Post Reply | Private Reply | To 1 | View Replies]

To: BenLurkin

Don’t you dare try this on the home of an LEO or an elected official or an employee of the NSA, though.


8 posted on 06/29/2013 5:52:11 PM PDT by E. Pluribus Unum (Who could have known that one day professional wrestling would be less fake than professional news?)
[ Post Reply | Private Reply | To 1 | View Replies]

To: BenLurkin

9 posted on 06/29/2013 5:52:54 PM PDT by Rodamala
[ Post Reply | Private Reply | To 1 | View Replies]

To: VerySadAmerican

“If King George had this kind of technology and the Patriots didn’t, we’d still be part of England.”

No, I think the piece of real estate known as the 13 colonies might still be a part of England, but all the real patriots would be dead.

Think then, think now. BO and the rest of the stink in DC would like us who are the real patriots also to be dead.


10 posted on 06/29/2013 5:54:40 PM PDT by GGpaX4DumpedTea
[ Post Reply | Private Reply | To 7 | View Replies]

To: BenLurkin

BTT


11 posted on 06/29/2013 5:56:37 PM PDT by RedEyeJack
[ Post Reply | Private Reply | To 1 | View Replies]

To: BenLurkin

"..I could use this"

12 posted on 06/29/2013 5:56:51 PM PDT by Doogle (USAF.68-73..8th TFW Ubon Thailand..never store a threat you should have eliminated))
[ Post Reply | Private Reply | To 1 | View Replies]

To: GGpaX4DumpedTea

If the Patriots had this kind of technology, they wouldn’t have resigned Hernandez for 40 million.


13 posted on 06/29/2013 5:57:05 PM PDT by Pearls Before Swine
[ Post Reply | Private Reply | To 10 | View Replies]

To: Pearls Before Swine

“resigned” should be “re-signed”


14 posted on 06/29/2013 6:00:06 PM PDT by Pearls Before Swine
[ Post Reply | Private Reply | To 13 | View Replies]

To: BenLurkin

A Ham operator with a Function Generator could defeat this method. (I think)


15 posted on 06/29/2013 6:04:44 PM PDT by B4Ranch (AGENDA: Grinding America Down ----- http://vimeo.com/63749370)
[ Post Reply | Private Reply | To 1 | View Replies]

To: bigbob

Thanks, my way would have been pretty sticky!


16 posted on 06/29/2013 6:09:56 PM PDT by Mastador1 (I'll take a bad dog over a good politician any day!)
[ Post Reply | Private Reply | To 6 | View Replies]

To: BenLurkin

Here’s a video showing UWB thru-wall imaging in operation:

http://www.youtube.com/watch?v=i2F-xcoY2Rg


17 posted on 06/29/2013 6:10:05 PM PDT by bigbob
[ Post Reply | Private Reply | To 1 | View Replies]

To: BenLurkin

One of Big Brother’s new toys.


18 posted on 06/29/2013 6:11:59 PM PDT by Blood of Tyrants (Inside every liberal and WOD defender is a totalitarian screaming to get out.)
[ Post Reply | Private Reply | To 1 | View Replies]

To: bigbob
Here's a law enforcement through-wall sensor that detects Obamaphones, even if they are turned off, even if the battery has been removed: Manta Ray Cell Phone Detector
19 posted on 06/29/2013 6:24:31 PM PDT by Reeses
[ Post Reply | Private Reply | To 17 | View Replies]

To: Pearls Before Swine

LOL...but the Patriots do have this kind of technology...it’s called Tim Tebow! :) ... a wide receiver who can think like a quarterback ought to be able to catch 9 out of 10 thrown his way...built in tracking...and he knows with whom he should discuss it all...he has the knee for it...


20 posted on 06/29/2013 6:25:34 PM PDT by GGpaX4DumpedTea
[ Post Reply | Private Reply | To 13 | View Replies]

To: Mastador1

and the Warriors of the WoD will herald the shredding of the 4th even more.


21 posted on 06/29/2013 6:26:21 PM PDT by i_robot73 (We hold that all individuals have the Right to exercise sole dominion over their own lives - LP.org)
[ Post Reply | Private Reply | To 2 | View Replies]

To: BenLurkin

Uses technology similar to the old see thru walls glasses,, they always fogged up. :-)


22 posted on 06/29/2013 6:30:13 PM PDT by NormsRevenge (Semper Fi --)
[ Post Reply | Private Reply | To 1 | View Replies]

To: GGpaX4DumpedTea
LOL...but the Patriots do have this kind of technology...it’s called Tim Tebow! :)

I was roundly laughed at here for suggesting that, as a joke, when the police first started looking at Hernandez. Since then, I've seen some articles on the sports blogs suggesting the very same thing--Tebow is big, he's strong, he did the full combine and scored higher than most tight ends, etc. I don't think that will happen, though, outside of some trick plays.

23 posted on 06/29/2013 6:37:33 PM PDT by Pearls Before Swine
[ Post Reply | Private Reply | To 20 | View Replies]

To: bigbob

Thx!


24 posted on 06/30/2013 8:33:24 AM PDT by BenLurkin (This is not a statement of fact. It is either opinion or satire; or both)
[ Post Reply | Private Reply | To 17 | View Replies]

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
General/Chat
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson