Centimeter Positioning with a Smartphone-Quality GNSS Antenna

Abstract

This paper demonstrates for the first time that centimeteraccurate positioning is possible based on data sampled from a smartphone-quality Global Navigation Satellite System (GNSS) antenna. Centimeter-accurate smartphone positioning will enable a host of new applications such as globally-registered fiduciary-marker-free augmented reality and location-based contextual advertising, both of which have been hampered by the several-meterlevel errors in traditional GNSS positioning. An empirical analysis of data collected from a smartphone-grade GNSS antenna reveals the antenna to be the primary impediment to fast and reliable resolution of the integer ambiguities which arise when solving for a centimeter-accurate carrierphase differential position. The antenna’s poor multipath suppression and irregular gain pattern result in large timecorrelated phase errors which significantly increase the time to integer ambiguity resolution as compared to even a low-quality stand-alone patch antenna. The time to integer resolution—and to a centimeter-accurate fix—is significantly reduced when more GNSS signals are tracked or when the smartphone experiences gentle wavelength-scale random motion.