Indoor Global Positioning System with Centimeter Accuracy Using Wi-Fi [Applications Corner]

In this column, we present a time-reversal method for indoor localization that achieves centimeter accuracy with a single pair of off-the-shelf Wi-Fi devices. The high accuracy for localization is maintained under strong NLOS scenarios. With the exploitation of the inherent frequency and spatial diversities in Wi-Fi systems, it is capable of creating a large effective bandwidth to enable centimeter accuracy. Extensive experiment results in a typical office environment show that the centimeter accuracy as well as robustness against dynamics can be simultaneously achieved with a large effective bandwidth. The global GPS can achieve 3-15 m of accuracy by mapping the world into latitude and longitude coordinates. The presented “indoor GPS” can achieve 1-2 cm accuracy when an indoor environment is fingerprinted and mapped.