## 5 Conclusions  
This paper studies the effects of TIC1 and TIC2 on the convergence time and positioning accuracy in SF PPP, and analyzes its positioning performance during MS and NMS periods. By comparing the positioning performance in low, middle, and high latitude areas, the following conclusions are drawn:  
(1) Through statistical analysis of the SF PPP convergence time and positioning accuracy of the globally distributed stations, it was found that during the MS period, the TIC2 convergence time was shorter than TIC1 as a whole, with a minimum improvement of 3.9%. For TIC1, the convergence time in the MS period was longer than in the NMS period, and the maximum convergence time could be extended by 41.8%. (2) The stations distributed around the world were further subdivided into high latitude, mid-latitude, and low latitude areas. According to our statistical analysis, the influence of ionospheric disturbances was large at low latitudes, resulting in a convergence time increase. The effect of increasing tropospheric constraints was not as good as TIC1 in the NMS period. Since at high latitudes the influence of the ionosphere was moderate or low, the overall convergence time was shorter than in the low latitude regions. However, the number of stations in the high latitude area was only 20% of that in the mid-latitude area; therefore the accuracy of the GIMs and the ZTD products was slightly lower and the convergence time was longer than the mid-latitude area under the TIC1 and TIC2. During the MS period, it was shown that the convergence times for the TIC2 cases became shorter by about 1.5 min, 0 min, and 2 min for the low, middle, and high latitude areas, respectively, in comparison with the TIC1. For TIC1 in the NMS period compared to in the MS period the convergence times were shortened by at least 4 min, 0 min, and 7 min, respectively. Some mode convergence times were not shortened in the mid-latitude, and this was because the ionospheric activity in the mid-latitude region was less than that in the low-latitude region, and there were more stations, so the precision of the GIMs and ZTD products were also slightly higher. (3) On the whole, TIC1 and TIC2 had little effect on the final positioning accuracy in the MS period, and the overall maximum difference was not more than 2 cm. The positioning accuracy of TIC1 in the NMS period was improved, compared to the MS period, by at least 2 cm, except at the 68% level in the vertical direction. [PERSON], [PERSON], and [PERSON] conceived and designed the experiments; [PERSON] and [PERSON] performed the experiments and analyzed the data; [PERSON] drew pictures; [PERSON] and [PERSON] wrote the paper; All authors have read and agreed to the published version of the manuscript. The work was partially supported by the Fundamental Research Funds for the Central Universities (grant number: 2018 BSCXC25), partially sponsored by Postgraduate Research and Practice Innovation Program of Jiangsu Province (grant number: KYCX18_1952), and partially supported both by the National Natural Science Foundation of China (NO. 41674008, 41604006, 41804029). The authors thank the anonymous reviewer for their valuable comments. Thanks also go to IGS for data and GIMs provision and GFZ Potsdam for the Kp-index. Of course, thanks also go to the open-source software GAMP from the team of [PERSON] of Shandong University of Science and Technology. The authors declare no conflict of interest. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Scheme**} & \multicolumn{4}{c}{**Kinematic SF PPP (m)**} & \multicolumn{4}{c}{**Static SF PPP (m)**} \\ \cline{2-9}  & **H (95\%)** & **H (68\%)** & **V (95\%)** & **V (68\%)** & **H (95\%)** & **H (68\%)** & **V (95\%)** & **V (68\%)** \\ \hline TIC1\_MS & 0.535 & 0.223 & 0.702 & 0.138 & 0.186 & 0.082 & 0.215 & 0.060 \\ TIC2\_MS & 0.495 & 0.214 & 0.659 & 0.136 & 0.175 & 0.079 & 0.151 & 0.040 \\ TIC1\_NMS & 0.380 & 0.179 & 0.444 & 0.091 & 0.127 & 0.064 & 0.159 & 0.042 \\ \hline \hline \end{tabular}
\end{table}