GPS/Galileo/BDS-2/BDS-3 full-frequency uncombined precise point positioning with fast ambiguity resolution and single-epoch ambiguity resolution on a global scale

Abstract

Abstract For global fast and reliable precise point positioning (PPP), two groups of common uncombined PPP ambiguity resolution (AR) modes, fast and single-epoch, were implemented with the full-frequency signals of the GPS, Galileo, BDS-2 and BDS-3 constellations. A series of wide-lane (WL) uncalibrated phased hardware delay biases (UPDs) and narrow-lane (NL) UPDs of the GNSS MEO satellites were generated and transformed to full-frequency UPDs using 15 days of data in 2022 from 104 global stations. The performance of the full-frequency (FF) float, WL AR (WAR), and cascaded WL and NL AR (CAR) PPPs were investigated by comparing with the dual-frequency (DF), triple-frequency (TF) and quad-frequency (QF) solutions in two groups of positioning experiments using another 40 global stations. Results illustrated that the FF CAR PPP performed the best. In the fast AR PPP experiment, the percentages of convergence time within 2 min, 5 min and 10 min of the FF CAR PPP reached 20.3%, 68.7% and 98.6%, respectively. An average convergence time of 4.3 min was achieved. The average RMSs of the positioning errors in the east, north and up components during the initial 10 min were 0.04 m, 0.04 m and 0.18 m, respectively. In the single-epoch AR PPP experiment, the RMSs of the positioning errors in the three components of the FF CAR PPP were 0.07 m, 0.08 m and 0.28 m, respectively. The percentages of the positioning errors in the horizontal direction within 0.1 m, 0.3 m and 0.5 m reached 89.0%, 96.0% and 99.1%, respectively.