An assessment of wide-lane ambiguity resolution methods for multi-frequency multi-GNSS precise point positioning

Abstract

We assess the time-to-first-fix (TTFF) and the ambiguity fixing rate of two PPP wide-lane ambiguity resolution (WL-AR) methods, namely the geometry-based and ionospheric-free (GB-IF) method, and the geometry-free and ionospheric-free (GF-IF) method. First, an optimal GF-IF WL linear combination is selected based on the ratio between the code and carrier phase measurement noise ($RT$). Then, the relation between ambiguity variance and satellite geometry in the GB-IF WL-AR is investigated. Both simulated and real data from 31 GNSS stations over 37 consecutive days in 2017 were used. Numerical results show that the GF-IF WL-AR method has shorter TTFF and higher ambiguity fixing rate compared to the GB-IF method when $RT\le 150$. However, when $RT\ge 150$, the GB-IF method outperforms the GF-IF method. Depending on RT values used, 2–10 min would be required to resolve the WL ambiguities when using GNSS measurements with one second sampling rate.

Keywords:

• Precise point positioning (PPP)
• Wide-lane ambiguity resolution (WL-AR)
• Triple-frequency PPP
• Multi-GNSS PPP
• Partial ambiguity resolution (PAR)

Acknowledgements

Geoscience Australia, CNES and the IGS are acknowledged for providing the GNSS data from the Australian Regional GNSS Network as well as the satellite orbits, clocks and biases. The Australia Award Scholarship Scheme is also gratefully acknowledged for supporting the first author in pursuing his Ph.D. studies at RMIT University, Melbourne, Australia.