GPS Galileo BDS3 LEO uncalibrated phase delays estimation and tight combination precise point positioning with...

Multi-system precise point positioning (PPP) can increase the number of observing satellites and improve the geometric configuration between the receivers and the satellites, and low-Earth orbit (LEO) satellites have fast motion and low orbital altitude, so the addition of LEO satellites can substantially improve the positioning accuracy. In this study, we simulated LEO observations, estimated the wide-lane (WL) and narrow-lane (NL) uncalibrated phase delays (UPDs) of the global positioning system (GPS), Galileo satellite navigation system (Galileo), Beidou-3 navigation satellite system (BDS-3) and LEO, performed multi-system tight-combination PPP and PPP-ambiguity resolution (AR) for stations in high, medium and low latitudes. The WL UPDs have good stability within 10 days, and more than 97% of the posterior residuals of each system are less than 0.25 cycles; the NL UPDs have good stability within one day, and more than 86% of the posterior residuals of each system are less than 0.25 cycles. This reflects that the UPD products have good quality and can be used for PPP-AR. Positioning results show AR can improve the positioning performance whether in high, medium or low latitudes; multi-system tight combination PPP can also improve positioning accuracy, accelerate the convergence time, and improved the success fix rate of AR, especially the addition of LEO satellites, which improves the positioning performance to a large extent.