3D-mapping-aided PPP-RTK aiming at deep urban canyons
Published in Journal of Geodesy, 2022
Recommended citation: Xin, S., Geng, J., Zhang, G., Ng, H.-F., Guo, J., & Hsu, L.-T. (2022). 3D-mapping-aided PPP-RTK aiming at deep urban canyons. Journal of Geodesy, 96(10), 78. https://doi.org/10.1007/s00190-022-01666-1. https://link.springer.com/article/10.1007/s00190-022-01666-1
As a hot topic in the GNSS community in recent years, PPP-RTK integrates the advantages of PPP and RTK, aiming to quickly realize centimeter-level single point positioning with ambiguity resolution. However, PPP-RTK still faces challenges in difficult urban environments. The performance of precise positioning will seriously deteriorate by the receptions of complex multipath and NLOS (non-light-of-sight) signals. The 3D-mapping-aiding (3DMA) method has been proven effective in urban navigation and positioning, such as detecting and excluding NLOS satellites. But the rough excluding strategy may cause more insufficient satellites. Thus, this study proposes a 3D-mapping-aided weighting algorithm to enhance the performance of PPP-RTK in complex urban environments. We modeled the 3DMA weighting function first by analyzing static GNSS data in various urban environments. Then, the proposed algorithm was applied to both static and kinematic positioning experiments. According to the results, the 3DMA weighting can be complementary to the classic C/N0 weighting: the 3DMA weighting can identify those poor measurements with high-C/N0 in urban environments while the C/N0 takes only a rough and preliminary diagnostic of the measurements. It could accelerate convergences and mitigate some outliers in slight and medium urban environments. In deep urban environments, it could achieve positioning availability of more than 90% with a horizontal precision of better than 20 cm, while the availability of traditional PPP-RTK without 3DMA may be less than 50%. The RMSs in horizontal components of the positioning errors after convergence are generally less than 10 cm while classic PPP-RTK reaches only the sub-meter level most of the time. We believe the 3DMA algorithm can benefit the precise GNSS positioning in urban canyons.
Recommended citation: Xin, S., Geng, J., Zhang, G., Ng, H.-F., Guo, J., & Hsu, L.-T. (2022). 3D-mapping-aided PPP-RTK aiming at deep urban canyons. Journal of Geodesy, 96(10), 78. https://doi.org/10.1007/s00190-022-01666-1.