## 4 Results and Discussion
### Different Latitudes Area Results
#### 4.2.2 Middle-Latitude Area Results  
In order to verify the results for the middle-latitude area, the positioning accuracy and convergence time of SF PPP in static and dynamic modes during MS and NMS periods were analyzed.  
It can be concluded from Figure 8, Figure 9, and Table 6 that the convergence time of TIC1 in the NMS period was the shortest in the horizontal component. The convergence time of the TIC2 in the MS period was the shortest in the vertical component, except for at the 68% level, where it was slightly longer than the shortest convergence time, which was 0.5 minutes. At the 95% level, the TIC2 was comparable to the TIC1 in the MS period, and addition of tropospheric constraints reduced the convergence times by 5.5% (horizontal component) and 33.8% (vertical component) for the kinematic mode, and for the static mode they were reduced by 3.4% (horizontal component) and 31.9% (vertical component). At the 68% level, convergence time was reduced by 9.6% in the horizontal component in the kinematic mode. In the static mode, the convergence times were equal. However, at the 68% level, the convergence time of TIC2 was 0.5 min longer than the TIC1 in the vertical component. The results showed that TIC1 in the NMS period in the 68% and 95% level of kinematic and static modes accelerated the convergence. The convergence time improved by at least 5.6% compared to in the MS period. Of course, at the 68% level the convergence times were equal in the vertical component.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Scheme**} & \multicolumn{4}{c}{**Kinematic SF PPP (min)**} & \multicolumn{4}{c}{**Static SF PPP (min)**} \\ \cline{2-9}  & **H (95\%)** & **H (68\%)** & **V (95\%)** & **V (68\%)** & **H (95\%)** & **H (68\%)** & **V (95\%)** & **V (68\%)** \\ \hline TIC1\_MS & 72.5 & 36.5 & 71.0 & 0.0 & 29.0 & 21.0 & 36.0 & 0.0 \\ TIC2\_MS & 68.5 & 33.0 & 47.0 & 0.5 & 28.0 & 21.0 & 24.5 & 0.5 \\ TIC1\_NMS & 43.0 & 23.5 & 64.5 & 0.0 & 23.0 & 15.5 & 34.0 & 0.0 \\ \hline \hline \end{tabular}
\end{table}
Table 6: The convergence times of GPS static and kinematic SF PPP in MS and NMS of TIC1 or TIC2.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Scheme**} & \multicolumn{4}{c}{**Kinematic SF PPP (min)**} & \multicolumn{4}{c}{**Static SF PPP (min)**} \\ \cline{2-9}  & **H (95\%)** & **H (68\%)** & **V (95\%)** & **V (68\%)** & **H (95\%)** & **H (68\%)** & **V (95\%)** & **V (68\%)** \\ \hline TIC1\_MS & – & 104.5 & – & 15.0 & 90.5 & 50.0 & 65.0 & 15.0 \\ TIC2\_MS & – & 97.0 & – & 0.0 & 83.0 & 48.5 & 44.0 & 0.0 \\ TIC1\_NMS & – & 85.0 & – & 10.0 & 72.5 & 44.5 & 54.5 & 11.0 \\ \hline \hline \end{tabular}
\end{table}
Table 4: The convergence times of GPS static and kinematic SF PPP in MS and NMS of TIC1 or TIC2.  
\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 & 0.587 & 0.235 & 0.534 & 0.114 & 0.262 & 0.103 & 0.201 & 0.044 \\ TIC2\_MS & 0.567 & 0.231 & 0.505 & 0.127 & 0.257 & 0.101 & 0.138 & 0.055 \\ TIC1\_NMS & 0.508 & 0.216 & 0.505 & 0.110 & 0.243 & 0.094 & 0.189 & 0.044 \\ \hline \hline \end{tabular}
\end{table}
Table 5: The RMS of GPS static and kinematic SF PPP in MS and NMS of TIC1 or TIC2.  
The laws in Tables 6 and 7 are similar, except that the RMS values of TIC1 during the MS period and the NMS period became smaller. In the middle latitudes, influence of the ionosphere was moderate  
Figure 8: The GPS kinematic SF PPP convergence performance in different constraint schemes during the MS and NMS periods.  
Figure 9: The GPS static SF PPP convergence performance in different constraint schemes during the MS and NMS periods.  
or low, which was comparable to the low-latitude region, so the difference in positioning results was small in both environments.