Indoor GPS with centimeter accuracy using WiFi

Indoor positioning systems are drawing ascending attention from the academia as well as industry, motivated by a wide variety of indoor location-based services. Among the existing indoor positioning systems, WiFi-based schemes are more favorable because of the ubiquitous WiFi infrastructures. However, both strong non-line-of-sight scenario and severe ambiguity among location-specific fingerprints prevent most existing WiFi-based indoor positioning systems from achieving centimeter accuracy for localization. In this paper, we propose an indoor positioning system which achieves centimeter accuracy and maintains the performance under non-line-of-sight scenarios using a single pair of off-the-shelf WiFi devices. By harvesting the inherent diversity in WiFi systems, the proposed indoor positioning system formulates a large effective bandwidth to provide a fine-grained location-specific fingerprint with a much higher resolution compared with the fingerprints in most WiFi-based indoor positioning systems. Extensive experiment results in a typical indoor environment show that the centimeter accuracy as well as robustness against environment dynamics can be achieved simultaneously with a large effective bandwidth.