We all know how cool Microsoft's Kinect peripheral is. It has the ability to track the position of a person in a room without said person needing to hold a transmitter, and it can read hand gestures, understand voice commands, recognize facial expressions and even measure heart beats. However it only really works in the room it's placed in, as it relies on several cameras for its array of functions.

MIT's newly-developed human-tracking sensor doesn't quite have the function set or accuracy of the Kinect, but it does manage to do something the Kinect can't: track the position of people through walls. Rather than using cameras, MIT's device uses three radio antennas that are spaced around a meter apart, which then measure radio wave reflections from a person moving on the other side of a wall. Through triangulation, the position of the moving person can be shown on the system's monitor to within 10cm.

While the researchers at MIT's Computer Science and Artificial Intelligence Laboratory eventually want to bring the technology to the market, there are some issues to overcome before a commercial product can be made. One such issue is how easy it is to interfere with the system. Currently only one person can be tracked using the device, and anyone else moving in the local area causes significant interference; however in a few software iterations the researchers are hoping to track multiple people as silhouettes, like the Kinect does.

The overall size of the unit is also not particularly practical, meaning it will need to be shrunk down before mass production. MIT believes the system has a lot of potential though, being able to track when and where people in retailers stop to look at displays, or when residents in an elderly care facility fall down or stop moving for extended periods.

With significant research and development still to be done to make the system ready for real-world use, it could still be many years before we'll see radio-tracking implemented in the wild. However the team at MIT will continue to work on the system, and one day we might find ourselves being tracked in a hidden and very clever way.