MIT turns Wi-Fi Into Indoor GPS

http://spectrum.ieee.org/tech-talk/telecom/wireless/mit-turns-wifi-into-indoor-gps

From the IEEE Spectrum article:

“Vasisht and Katabi tested Chronos on an AscTec Hummingbird quadcopter fitted with an Intel 5300 Wi-Fi card and a Go-Pro camera. The drone was set to stay 1.4 meters from a netbook, shooting photos of the computer as it moved. Chronos was able to keep the drone within just 4 cm of its programmed distance.”