PRIDE PPP-AR: an open-source scientific software with all-frequency PPP ambiguity resolution for geodesy, geophysics and photogrammetry applications

The modernized GNSS transmit more signals on various frequencies to suit different application scenarios. However, for a long time, ambiguity resolution has been available to PPP users only on a few signal frequencies specified by the PPP service provider, which prevents other signal frequencies from being used for high-precision positioning applications. Recently, the GNSS Research Center of Wuhan University offered a new version of open-source PRIDE PPP-AR software and a set of “all-frequency” PPP-AR products, that supports PPP users in achieving undifferenced ambiguity resolution on any dual-frequency ionosphere-free combination based on the same satellite phase clocks. The new feature of PRIDE PPP-AR was tested with GPS/Galileo/BDS observations from 200 multi-frequency IGS stations in the first 9 months of 2022. The mean wide-/narrow-lane ambiguity fixing rates can achieve 90% on most of the common dual-frequency combinations, including GPS L1/L2, the combination of Galileo E1 and Galileo E5a/E5/E5b/E6, and BDS-3 B1C/B2a and B1I/B2I. On the other common dual-frequency combinations except for the BDS-2 B1I/B2I, the mean wide-/narrow-lane ambiguity fixing rates can achieve 80%. On all the above dual-frequency combinations, the positioning RMS errors compared with the IGS weekly solutions are about 2 mm in the east and the north directions, and below 7 mm in the high direction. Additionally, the new version of PRIDE PPP-AR enables precise orbit determination for LEO satellites. The TurboEdit algorithm was improved with forward and backward moving window averaging (FBMWA) method to accommodate the need for achieving ambiguity resolution on fast motion objects. A comparison between the computed orbits and JPL’s precise orbits for GRACE-FO in 2019 shows that the 3D RMS difference is within 1.7 cm. The PRIDE PPP-AR was first released in 2019 and dedicated to expanding the scope of PPP-AR in geodetic researches. After several updates, this GNSS analysis tool now supports multi-day continuous processing, processing of very-high-rate GNSS data, and quasi-real-time processing with real-time archived PPP products. With the new features of all-frequency PPP-AR and PPP-AR on LEO satellites, the new version of PRIDE PPP-AR will be able to take full advantage of GNSS modernization to improve high-precision positioning accuracy in more research areas.