Realization and Evaluation of Real-Time Uncombined GPS/Galileo/BDS PPP-RTK in the Offshore Area of China’s Bohai Sea

Abstract

The real-time kinematic (RTK) technology has been widely used as the high-precision positioning method in the offshore area. However, RTK requires a bi-directional communication and groups measurement errors together, thereby limiting its mass-market applications. Combining the advantages of precise point positioning (PPP) and RTK, PPP-RTK has become one of the hotspot technologies in the mass market. In this contribution, we propose the uncombined multi-GNSS PPP-RTK model using uncalibrated phase delays (UPDs) estimated from the legacy ionosphere-free and Melbourne-Wübbena combination. With the UPDs estimated based on 14 regional stations, we conduct PPP ambiguity resolution (AR) at 3 augmentation stations and derive precise atmospheric corrections, i.e., RMS of zenith tropospheric and slant ionospheric correction can be up to 4.89 mm and 2.20 cm, respectively. After applying atmospheric correction, the correct fixed solution of four on-board kinematic experiments can be better than 95% and the positioning accuracy can be better than 5 cm in both horizontal and vertical direction, showing the encouraging performance similar to RTK in the offshore area.

Keywords:

• ambiguity resolution
• atmospheric correction
• GPS/Galileo/BDS
• offshore
• PPP-RTK

Acknowledgements

We thank the Chinese Academy of Sciences (CAS) for providing real-time orbit and clock offset products and the GEESPACE Technology Co., Ltd for providing the regional observation data.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was funded by National Natural Science Foundation of China (No.41574010, 41604013 and 41904039), Guangxi Key Laboratory of Spatial Information and Geomatics (No.19-185-10-20).