During tests, the device calculated time-of-flight down to 0.5 nanoseconds, making it 20 times more accurate than other systems. In a four-room apartment, researchers picked out a user's correct room location 94 percent of the time, and figured out if someone was using WiFi inside a cafe with 97 percent accuracy. They also tested it on a drone, keeping it a set distance away from the operator with a 2-inch margin of error.

Previous attempts at WiFi user calculation required multiple routers for triangulation, but MIT's system works with a single access point. There's no word on plans to commercialize the product, but the fact that the CSAIL team made a working prototype is always a promising sign. If the tech was incorporated into a router, it could shut out snoopers or internet thieves in many circumstances, making public and private WiFi much less of a security crapshoot.