Pseudolite system-augmented GNSS real-time kinematic PPP

Global navigation satellite systems (GNSS) precise point positioning (PPP) allows a user to perform high-accuracy absolute positioning using a stand-alone receiver. However, a long convergence time for GNSS PPP is a critical obstacle to its wide application. Since pseudolites (PLs) are relatively close to receivers, moving receivers can produce rapid spatial geometry changes, which facilitates the fast convergence of parameters. Based on this advantage of the pseudolite system (PLS), we investigate the PLS-augmented GNSS real-time kinematic PPP. Single-frequency PLS raw observations are combined with dual-frequency GNSS raw observations by an undifferenced and uncombined PPP model to augment the GNSS PPP. A real-world experiment demonstrated that the convergence time was dramatically shortened by 99.5% from about 900 s to nearly 4 s using PLS augmentation. In the 900-s sessions, the average success rate of GNSS ambiguity resolution can reach approximately 90% using PLS augmentation. Furthermore, PLS-augmented GNSS PPP showed a better positioning accuracy compared with GNSS-only PPP. The contributions of the PLS are still remarkable even with a short-time PLS augmentation. For example, after position parameters converged, if PLS can provide another 8-s augmentation, GNSS ambiguity parameters will also converge, then GNSS PPP can work independently and provide continuous high-precision positioning. In addition, longer augmentation times can promote higher success rates of GNSS ambiguity resolution. In summary, the positioning accuracy, convergence speed, and success rate of GNSS ambiguity resolution of GNSS PPP are significantly improved using PLS augmentation.

Automated summary

GNSS PPP augmented with PLS significantly improves positioning accuracy, convergence speed, and success rate of ambiguity resolution.