Researchers create a more accurate alternative to Wi-Fi for tracking people through walls

Back in June, MIT researchers revealed they had figured out how to use Wi-Fi to track moving objects through walls. Today, the same team announced they have refined their system to be even more precise by switching to radio signals.

The system, known as “WiTrack,” works with the help of four antennae. One transmits a signal and the other three take in signals that bounce back. Based on how long it takes a signal to return, WiTrack can calculate an object’s distance from the antennae and map movement.


“Because of the limited bandwidth, you cannot get very high location accuracy using Wi-Fi signals,” graduate student Fadel Adib said in a release. “WiTrack transmits a very low-power radio signal, 100 times smaller than Wi-Fi and 1,000 times smaller than what your cell phone can transmit.”

Along with improving the precision of the tracking to 4 to 8 inches, WiTrack’s advantage over the earlier WiVi technology unveiled in June is that it can track three dimensional movement and pinpoint someone’s exact location in a room. WiVi only indicated how far a person was from the antennae.

WiTrack 3D tracking

The researchers said WiTrack could notice when a senior falls and needs help or be used for gaming. In June, they noted WiVi could be integrated into the internet of things or used to track criminals or people trapped in buildings.

“Today, if you are playing a game with the Xbox Kinect or Nintendo Wii, you have to stand right in front of your gaming console, which limits the types of games you can play,” computer science and engineering professor Dina Katabi said in the release. “Imagine playing an interactive video game that transforms your entire home into a virtual world. The game console tracks you as you run down real hallways away from video game enemies, or as you hide from other players behind couches and walls.”

Unlike WiVi, WiTrack can only track one person at a time. The researchers will next focus on adding that as an option.