The effect of ambiguity resolution on the precision of the GPS/Galileo PPP using a u-blox ZED-F9P low-cost GNSS receiver

Abstract

Thanks to the increasing number of low-cost dual-frequency GNSS receivers available on the market, the usability of these receivers for geodetic applications is increasing. Recently, PRIDE Lab at GNSS Research Center of Wuhan University has started to produce GNSS observable-specific phase biases for all-frequency. This enables precise point positioning with ambiguity resolution (PPP-AR) not only for conventional frequencies but also for other arbitrary frequencies. In this work, static and kinematic PPP-AR precision of the u-blox ZED-F9P low-cost GNSS receiver are investigated by comparing it with a geodetic-grade GNSS receiver using GPS-only, Galileo-only, and GPS + Galileo combinations for nearly two months period. Wide-lane (WL) and Narrow-lane (NL) AR fixing rates, cycle slips, code multipath, and frequency availability are also investigated for both receivers. In the positioning domain, GPS-only, Galileo-only, and GPS + Galileo PPP positioning precision using float ambiguities is significantly improved after AR for both receivers. GPS + Galileo PPP provides the best precision comparing with the other PPP solutions for both receivers using float and fix ambiguities. For static GPS + Galileo PPP-AR, the standard deviation of north, east, and up components are computed as 2.7/1.7/3.2 mm and 2.2/2.3/5.4 mm for the geodetic receiver and the u-blox receiver, respectively. The results also reveal that kinematic PPP-AR for the u-blox receiver is not as reliable as the geodetic-grade receiver yet suggesting potential for improvement in future iterations.