## 3 Results
### Performance of Multi-System PPP with Precise Products from Different Analysis Centers
#### 3.4.2 Static Position Solutions
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**System Combination**} & \multicolumn{3}{c}{**Convergence Time (min)**} & \multicolumn{3}{c}{**Positioning Accuracy (cm)**} \\ \cline{2-6}  & **East** & **North** & **Up** & **East** & **North** & **Up** \\ \hline G-PPP & 24.1 & 15.2 & 26.1 & 2.7 & 2.2 & 4.4 \\ R-PPP & 61.3 & 42.6 & 69.9 & 5.1 & 3.4 & 7.1 \\ E-PPP & 17.7 & 13.1 & 33.5 & 4.1 & 2.8 & 6.0 \\ C-PPP & 32.1 & 17.5 & 33.2 & 2.9 & 2.1 & 5.7 \\ GR-PPP & 11.3 & 6.2 & 11.4 & 1.4 & 1.2 & 3.2 \\ GE-PPP & 11.3 & 6.1 & 14.3 & 1.4 & 1.2 & 3.1 \\ GC-PPP & 10.8 & 6.2 & 12.1 & 1.2 & 1.0 & 2.8 \\ GJ-PPP & 22.0 & 14.9 & 25.5 & 2.2 & 1.9 & 3.7 \\ GRECJ-PPP & 8.0 & 4.0 & 8.1 & 1.0 & 0.8 & 2.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 14: Kinematic positioning accuracy and convergence time of post-processed PPP (long-term performance of PPP based on daily observations) with GFZ products for different system combinations using the datasets from 29 stations spanning a week. the east, north and up directions, respectively, while the corresponding errors of real-time kinematic GREC-PPP have a varying range of 3, 3 and 5 cm in the three directions, respectively. Table 16 illustrates the statistical kinematic positioning accuracy and convergence time of real-time PPP with CNES products for different system combinations. It should be noted that all the following statistics are only valid for the long-term performance of PPP. Both the real-time kinematic positioning accuracy and convergence time can benefit from the multi-system combination. The convergence time improvement is 78%/86%/82% for GR-PPP over R-PPP, 39%/59%/55% for GE-PPP over E-PPP, 73%/72%/73% for GC-PPP over C-PPP, and 42%/49%/43% for GREC-PPP over G-PPP in the east/north/up directions, respectively, while the corresponding improvement on the positioning accuracy is 64%/50%/54%, 61%/55%/49%, 60%/59%/52%, and 48%/38%/31% in the three directions, respectively. The real-time kinematic GREC-PPP can achieve a convergence time of 11.5/6.9/13.0 min, and a positioning accuracy of 1.7/1.6/3.6 cm in the three directions, respectively. The real-time kinematic PPP even has slightly better positioning performance compared with some cases of post-processed kinematic PPP results shown in Tables 13-15, including the convergence time of G-PPP with WHU and GFZ products, of E-PPP with WHU products in east and up directions, and of GE-PPP with WHU products in east direction, as well as the positioning accuracy of G-PPP and E-PPP with WHU products in east direction. Similar to the static PPP, the performance degradation is obvious for real-time kinematic R-PPP and C-PPP over the post-processed kinematic ones. Compared with the post-processed kinematic R-PPP, the convergence time of real-time kinematic R-PPP is lengthened by 9.9-21.4, 15.6-25.7 and 15.7-28.1 min in the east, north and up directions, respectively, while the corresponding positioning accuracy is decreased by 2.2-2.7, 0.9-1.3 and 2.7 cm in the three directions, respectively. As for C-PPP, the degradation is 20.6-22.8, 14.7-17.6 and 26.2-27.6 min on the convergence time, and 2.7-3.0, 2.1-2.3 and 3.0-3.7 cm on the positioning accuracy in the three directions, respectively. Regarding the other combination cases, the performance degradation is confined to 8.6 min and 1.8 cm in terms of the convergence time and positioning accuracy, respectively. The post-processed kinematic GREC-PPP shortens the convergence time by 2.9-4.7, 2.9-3.6 and 4.9-5.2 min (25-41%, 42-52% and 38-40%), and improves the positioning accuracy by 0.6-0.7, 0.8 and 1.0-1.1 cm (35-41%, 50% and 28-31%) in comparison with the real-time kinematic GREC-PPP in the three directions, respectively. The real-time kinematic PPP increases the position errors and convergence time by a factor of 2.7 times on average over the real-time static PPP (see Table 12). Figure 13: Epoch-wise position errors of kinematic PPP using CNES real-time precise products at station KIR0 on 17 May 2020.