An investigation of the contribution of multi-GNSS observations to the single-frequency precise point positioning method and validation of the global ionospheric maps provided by different IAACs

This study presents the contribution of multi-GNSS (Global Navigation Satellite System) observations to the kinematic single-frequency precise point positioning (SF-PPP) technique and examines the effect of twenty-one different global ionosphere maps (GIMs), which are relied on 1/2 day predicted, broadcast, rapid, and final observations, provided to the GNSS-users by eight different Ionosphere Associate Analysis Centers (IAACs) on the SF-PPP technique. Two different experimental data were used in this contribution. First, thirty International GNSS Service (IGS) station observation data from the IGS network were evaluated, and then a kinematic vehicle experiment was performed. Both the contribution of multi-GNSS observations to the SF-PPP technique and the effect of GIMs on the SF-PPP were investigated employing these two experimental data. The outcomes clearly demonstrate that the quad combination improves the position accuracy of the SF-PPP technique in the horizontal component by an average of 39%, 24%, and 11%, respectively, compared to those obtained from single, dual, and triple constellations. Moreover, the results clearly indicate that the GIMs considerably shorten the convergence time of the SF-PPP technique, while among the GIMs, CARG, CASG, CODG, and IGSG provide more position accuracy improvements than others for horizontal and vertical components. Finally, the findings clearly show that the C1PG and C2PG, which are 1/2 day predicted GIMs, are quite promising, although the CKMG and GPSG products based on broadcast observations are not yet at the required accuracy.