Validation and assessment of multi-GNSS phase bias products from IGS analysis centers

Abstract

Phase bias plays a crucial role in precision point positioning (PPP) with ambiguity resolution. Currently, an increasing number of analysis centers are being of releasing multi- Global Navigation Satellite System (GNSS) phase bias products. However, it remains uncertain how different phase bias products, receiver types, and GNSS systems combinations might impact user-side positioning performance and ambiguity resolution capabilities. In view of this, this contribution systematically investigates the effects on PPP with ambiguity resolution. Four types of receivers, including SEPTENTRIO POLARX5, LEICA GR50, JAVAD TRE_3 DELTA, and TRIMBLE ALLOY, are selected, and six types of GNSS system combinations, namely, GPS, Galileo, BDS3, GPS/Galileo, GPS/BDS3, GPS/Galileo/BDS3, are used, and the phase bias products from OSB (Observable-specific Bias)-CODE (Center for Orbit Determination in Europe), OSB-CNES/CLS (Centre National d’Etudes Spatiales Geodesy Team), OSB-GFZ (German Research Centre for Geosciences/Germany), OSB-WHU (Wuhan University), OSB-CNES/NAV (Centre National d’Etudes Spatiales Navigation Team), IRC (Integer Recovery Clock)-CNES/CLS, IRC-GFZ are adopted for the numerical experiment. Compared with the float-solution, the results show that the accuracy of PPP fixed-solution with single-system can be improved 1 cm–3 cm, and the convergence time is reduced 2 min–15 min. The positioning performance using the seven phase bias products for any single-system satisfies the following order from the best to the worst: OSB_WHU > OSB_CODE > OSB_CNES/CLS ≈ OSB_CNES/NAV > OSB_GFZ > IRC_CNES/CLS ≈ IRC_GFZ, but the performance of ambiguity resolution do not present certain characteristics. Meanwhile, the ambiguity-fix success-rate and Time to First Fix can keep at 80%–96% and 20 min–40 min with single-system, respectively. In the case of multi-system, although the difference in the positioning performance among the phase bias products is not significant, the multi-system outperforms the single-systemin terms of both positioning performance and ambiguity resolution. However, the difference between the dual-system and the triple-system is smaller. In addition, the positioning performance corresponding to different receiver types also shows distinction, while there is no significant difference in the ambiguity resolution performance between different receiver types.