MIT's Computer Science and Artificial Intelligence Laboratory has created a new system called Chronos that can accurately detect the position of electronic devices in a room -- as well as the users who are carrying them -- within tens of centimeters using Wi-Fi signals only. "Chronos works without the aid of any secondary sensors, only using a technology called time-of-flight calculation, which measures the time it takes data to travel from the WiFi access point to the user's device," according to an article on Softpedia, citing a paper (PDF) that the researchers presented at a USENIX symposium in March. "MIT researchers say that by multiplying the time-in-flight value they receive from each user with the speed of light, they were able to detect each user's distance to the central Wi-Fi access point."
