Performance of hourly precise point positioning with ambiguity resolution

Precise Point Positioning (PPP) using GPS has become a valuable tool during the past ten years, but the ambiguity resolution at a single station is constantly considered an innovative and difficult issue within PPP. In this study, the recent advancement on this issue is introduced briefly before two assessments on the performance of hourly PPP with ambiguity resolution using both static and kinematic data sets are carried out. In the static test, about 80 stations from the European Reference Frame Permanent Network are employed to determine the Uncalibrated Hardware Delays (UHD) that prevent the integer ambiguity resolution at a single station. Then 17 IGS stations are used to conduct hourly PPP using these UHD, in which more than 97% of independent ambiguities are fixed successfully to integers. The accuracy of position estimates is also improved by more than 66%, in which the horizontal accuracy achieves a sub-cm level in the fixed solutions. In addition, a data set collected onboard an ocean-going vessel using three separated receivers is used to test hourly kinematic PPP. A network consisting of 16 stations around the sailing area, in which the nearest one is still more than 400 km away from this vessel, is used to determine the UHD. Through ambiguity resolution, the hourly baseline accuracies between the three receivers are improved on average from 2.6 cm to 1.0 cm. Finally, it is proposed that a service aiming at ambiguity resolution at a single station is feasible and promising, which could be provided by GPS network operators in future.