Multi-GNSS precise point positioning with raw single-frequency and dual-frequency measurement models

摘要: The emergence of multiple satellite navigation systems, including BDS, Galileo, modernized GPS, and GLONASS, brings great opportunities challenges for precise point positioning (PPP). We study the contributions various GNSS combinations to PPP performance based on undifferenced or raw observations, in which signal delays ionospheric must be considered. A priori knowledge, such as regional global corrections, strengthens estimation delay parameters. models are generally more suitable single-, dual-, multi-frequency data processing single combined constellations. Another advantage over ionospheric-free is that avoid noise amplification by linear combinations. Extensive evaluations conducted with multi-GNSS sets collected from 105 MGEX stations July 2014. Dual-frequency results each constellation show convergence time solution usually shorter than solutions, while accuracy shows improvement GLONASS system. In addition, demonstrate advantages high latitude areas, this impact less obvious GPS/GLONASS configuration. have also indicated BDS GEO satellites negative impacts given current "poor" orbit clock knowledge satellites. More generally, shown improvements 60 % both single- dual-frequency results, after indicates no significant but an about 25 average single-frequency solutions.