Surveillance Device To Use Wi-Fi To See Through Walls

Some researchers that reside in England have created a prototype surveillance device that will allow you to spy on people inside buildings and behind walls. How does it do this? It does this by tracking the frequency changes as Wi-Fi signals that are generated by various wireless routers and access points bounce off of people as they move around their home(s). It’s quite interesting actually. I never thought that the technology was really there to see through walls and all. It makes you wonder what’s up next when it comes to military technology or just security technology in general, you know?

The device is the size if a suitcase, surprisingly. I personally would of thought it might be smaller, but since this is just a prototype, it’s not much to really worry about. The device has two antennae and a signal process unit that works as a “passive radar system” that can “see” through walls, according to PopSci.com. The prototype was able to successfully determine the location, speed, and direction of a person behind a one-foot-thick brick walls. Since this surveillance device only detects people through Wi-Fi signals, it is not able to detect people who are standing or still still.

The United Kingdom Military of Defense is looking into whether this device that was designed by Karl Woodbridge and Kevein Chetty of the University of College London, will be able to be used in “urban warfare” for scanning buildings, PopSci had reported. The paper on the research of the device, “Through-the-Wall-Sensing of Personnel Using Passive Bistatic WiFi Radar at Standoff Distances,” appeared in an April issue of iGeoscience and Remote Sensing, IEEE Transactions.

Straight from the abstract:

A series of experiments was conducted which involved personnel targets moving inside a building within the coverage area of a WiFi access point. These targets were monitored from outside the building using a 2.4-GHz passive multistatic receiver, and the data were processed offline to yield range and Doppler information. The results presented show the first through-the-wall (TTW) detections of moving personnel using passive WiFi radar. The measured Doppler shifts agree with those predicted by bistatic theory. Further analysis of the data revealed that the system is limited by the signal-to-interference ratio (SIR), and not the signal-to-noise ratio. We have also shown that a new interference suppression technique based on the CLEAN algorithm can improve the SIR by approximately 19 dB. These encouraging initial findings demonstrate the potential for using passive WiFi radar as a low-cost TTW detection sensor with widespread applicability.

Since there are already many concerns over the government’s use of mobile body scanner technologies, the development of a device that will allow someone to keep an eye on a person’s movements within his or her own home, will no doubt be met with an outcry. Surely this sort of device would not be allowed for public use in the United States, but it is very well possible in the United Kingdom.

Hopefully we’ll be getting some more details on this device soon, it actually sounds really interesting.

Let us know your thoughts in the comments below!