A New Coupled Method for Pseudolite System-Augmented GNSS Real-Time Kinematic PPP

A long convergence time for Global Navigation Satellite System (GNSS) Precise Point Positioning (PPP) is a critical hindrance to its widespread application. Due to pseudolites (PLs) are very close to receivers, moving users can generate rapid geometric variations, reduce the correlation between parameters, and thus accelerate parameter convergence. However, considering the limited coverage of pseudolite system (PLS), the augmentation time is limited. It is therefore crucial to make the GNSS PPP parameters (especially the GNSS ambiguity parameters) converge within the limited augmentation time. Therefore, the potential of PLS should be explored as much as possible, and the gains brought by PLS should be effectively utilized. In order to use the fixed solution of PLS more safely and reliably, a dual-filter tightly coupled (DF-TC) model is proposed. When the number of PLs is sufficient and the augmentation time is long enough, the positioning performances of all the couple models are not significantly different. In the case of short-time augmentation, the DF-TC model exhibits the best augmentation performance, it can significantly reduce the augmentation time required by GNSS, which means that the required coverage of PLS can be smaller and will be more flexible and convenient for applications.