Many scientists have issued health warnings about the near-ubiquitous presence of WiFi in our homes and in public.
Now there might be a new concern on the horizon – public WiFi signals that can identify and track groups of individuals, even if they are not holding a personal connected device.
As we have come to learn, one of the hallmarks of technology is dual- or multi-use capability. It is for this reason that we are softened up with all of the benefits, before being introduced to the darker side.
Researchers continue to pursue invisible, pervasive ways to track human beings. Below is a chronicle of how WiFi signals are being used in creative new ways to ensure that whether or not you have opted out of the latest gadgetry, you still will be caught in an ever-widening net of the latest surveillance tech.
A little more than two years ago, the first enhancement of Wi-Fi was labeled WiTrack. It marked an improvement over a discovery by MIT researchers a few months previous that they had called Wi-Vi. At the time, researchers were able to use dual signals to detect the general location of moving objects behind walls, but not an exact image.
WiTrack uses radio signals to pinpoint a person’s location more accurately. An MIT press release explained the significant difference between Wi-Vi and WiTrack: WiTrack operates by tracking specialized radio signals reflected off a person’s body to pinpoint location and movement. The system uses multiple antennas: one for transmitting signals and three for receiving. The system then builds a geometric model of the user’s location by transmitting signals between the antennas and using the reflections off a person’s body to estimate the distance between the antennas and the user. WiTrack is able to locate motion with significantly increased accuracy, as opposed to tracking devices that rely on wireless signals, according to Adib. “Because of the limited bandwidth, you cannot get very high location accuracy using WiFi signals,” Adib says. “WiTrack transmits a very low-power radio signal, 100 times smaller than WiFi and 1,000 times smaller than what your cell phone can transmit. But the signal is structured in a particular way to measure the time from when the signal was transmitted until the reflections come back. WiTrack has a geometric model that maps reflection delays to the exact location of the person. The model can also eliminate reflections off walls and furniture to allow us to focus on tracking human motion.”