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originally posted by: TEOTWAWKIAIFF
a reply to: Reverbs
Sounds like a new, updated, pick up book for the next generation!!
1 - Puppy
2 - Jerry Can
3 - Long hair, no shirt, mosh pit
4 - Tinder is the night!!
The passive radar process is actually quite simple. In any space that has WiFi, you are constantly being bombarded by 2.4GHz and 5GHz radio waves. When these waves hit a moving object, their frequency is altered (the Doppler effect). By carefully “sniffing” the WiFi signals, Woodbridge and Chetty are able to reconstruct an image any objects or humans that are moving on the other side of the wall.
In testing, this passive radar system is able to detect a person’s location, speed, and direction, through a foot-thick brick wall. One problem with Doppler-based systems is that they only work with moving objects — a would-be burglar or combatant can thwart these systems by standing still. With further work, though, the UCL engineers think they can increase the sensitivity of the system so that it can detect the movement of your ribcage as you breathe in and out.
Some setups can detect home intruders or track moving objects with one or two Wi-Fi antennas. Others use an array of antennas to build 2D images. But Holl says no one has used Wi-Fi to make a 3D hologram of an entire room and the stuff inside it.
"Our method gives you much better images, since we record much more signal. We scan the whole plane of a room," he says.
These antennas don't need to be big. They can be very small, like the ones in a smartphone," Holl says.