MIT turns Wi-Fi into an accurate indoor GPS
A recent discovery by researchers at MIT's Computer Science and Artificial Intelligence (CSAIL) department could be very important, as they have developed a way to detect nearby devices , including smartphones, within centimeters of each other.
Existing positioning systems typically rely on special beacons or simply determining location by listening to Wi-Fi access points. Also, such satellite technologies have been shown to be both accurate and not very accurate at all.
However, the new technology, called Chronos, uses Wi-Fi signals to figure out the precise location of their senders. Chronos works by having two Wi-Fi devices, a transmitter and a receiver, switch between 35 Wi-Fi frequency bands from 2.4 gigahertz to 5.8 GHz Wi-Fi simultaneously. The rate at which the signals accumulate is naturally different at each frequency. The transmitter switches between bands every 2 to 3 microseconds, and can compare the physical differences in the phase of each signal and figure out how long it took the signal to travel, which in turn allows it to locate it remotely.
With more modern smartphones and laptops having multiple Wi-Fi antennas, Chronos has the ability to not only understand the distance, but also the direction of the other device and precisely detect its relative position in space. It is said that Chronos can locate devices with an accuracy of 65 cm (or about 10 times the accuracy of GPS) using only off-the-shelf Wi-Fi cards, which is much more accurate than GPS. Therefore, it is useful for the kinds of applications that will be required from now on – especially in the context of the Internet of Things (IoT).
