Scientists in Germany have demonstrated a startling new form of surveillance: identifying people using nothing more than ordinary WiFi signals. By analyzing how radio waves bounce around a room, researchers can effectively “see” and recognize individuals — even if they are not carrying a device and even if their phone is turned off.
Hmm. The article appears to conflate multiple things?
One of them is “viewing” the RF spectrum to build up an image. The other is reading the unencrypted beamforming data from a router. That second one depends on people carrying a WiFi-capable piece of electronics with them doesn’t it? There has to be something for the beam to focus on, some sort of beacon signal.
Although I guess all it really needs is for the person to step between the router and a device connected to the router; that should enable analysis of the disruption patterns.
I don’t think a person has to carry anything. The tracking is based on measuring the interference a moving person (or a dog) creates between the router and a connected device like a range extender or a networked printer.