## 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{4}{c}{**Convergence Time (min)**} & \multicolumn{4}{c}{**Positioning Accuracy (cm)**} \\ \cline{2-7}  & **East** & **North** & **Up** & **East** & **North** & **Up** \\ \hline G-PPP & 11.8 & 5.7 & 15.6 & 0.6 & 0.3 & 1.2 \\ R-PPP & 18.1 & 9.1 & 19.3 & 0.6 & 0.4 & 1.5 \\ E-PPP & 11.4 & 6.7 & 18.0 & 0.6 & 0.5 & 1.3 \\ C-PPP & 15.3 & 9.1 & 16.4 & 0.7 & 0.4 & 1.3 \\ GR-PPP & 9.4 & 4.6 & 10.3 & 0.4 & 0.3 & 1.2 \\ GE-PPP & 8.2 & 4.4 & 10.5 & 0.4 & 0.4 & 1.1 \\ GC-PPP & 8.5 & 4.3 & 10.0 & 0.4 & 0.3 & 1.1 \\ GJ-PPP & 11.4 & 5.7 & 15.5 & 0.5 & 0.3 & 1.2 \\ GRECJ-PPP & 6.9 & 3.1 & 7.1 & 0.3 & 0.3 & 1.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Static 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. Figure 10: Epoch-wise position errors of static PPP using ESA final precise products at station KIR0 on 17 May 2020. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**System Combination**} & \multicolumn{4}{c}{**Convergence Time (min)**} & \multicolumn{4}{c}{**Positioning Accuracy (cm)**} \\ \cline{2-7}  & **East** & **North** & **Up** & **East** & **North** & **Up** \\ \hline G-PPP & 15.1 & 6.0 & 15.3 & 0.4 & 0.2 & 1.1 \\ R-PPP & 17.5 & 9.4 & 18.2 & 0.6 & 0.4 & 1.5 \\ E-PPP & 12.6 & 8.6 & 22.9 & 0.6 & 0.4 & 1.2 \\ C-PPP & 14.9 & 9.7 & 16.7 & 0.7 & 0.4 & 1.2 \\ GR-PPP & 8.3 & 4.0 & 8.6 & 0.3 & 0.2 & 1.2 \\ GE-PPP & 9.8 & 4.6 & 12.2 & 0.3 & 0.2 & 1.1 \\ GC-PPP & 8.8 & 4.1 & 10.3 & 0.4 & 0.2 & 1.0 \\ G1-PPP & 14.8 & 6.0 & 15.1 & 0.4 & 0.2 & 1.1 \\ GRECJ-PPP & 6.2 & 3.1 & 6.8 & 0.3 & 0.2 & 1.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Static positioning accuracy and convergence time of post-processed PPP (long-term performance of PPP based on daily observations) with W/HU products for different system combinations using the datasets from 29 stations spanning a week. As the number of available QZSS satellites is limited, the convergence time improvement of GJ-PPP over G-PPP is marginal, which is confined to tens of seconds. GRECJ-PPP achieves the shortest convergence time, the numerical value of which is 6.2/3.1/6.8, 6.9/3.1/7.1 and 5.9/2.6/6.3 min for the cases with WHU, GFZ and ESA products in the east/north/up directions, respectively. GRECJ-PPP shortens the convergence time by 59%/48%/56%, 42%/46%/54% and 43%/52%/57% over G-PPP for the three different precise products in the three directions, respectively. As for the effect of employed precise products on the convergence time, it is ignorable for C-PPP, GR-PPP, GC-PPP and GRECJ-PPP, and the difference is smaller than 1.7 min when adopting the precise products from different ACs. The convergence time of G-PPP with WHU products in the east direction is longer than that using the other two post-processed products by several minutes, and it is also the case for R-PPP with ESA products in the east direction, for E-PPP with WHU products in the east and up directions, and for GJ-PPP with WHU products in the east direction. The post-processed positioning accuracy of static PPP with the precise products from different ACs is found to be at a similar level, and the accuracy difference among each other is smaller than 0.3 cm. Figure 11 exhibits the epoch-wise position errors of static PPP using CNES real-time precise products for the four single-system cases and GREC-PPP at station KIR0 on 17 May 2020. It is seen that the positioning performance of E-PPP, C-PPP and R-PPP within the first five hours is significantly worse than G-PPP. The real-time static R-PPP has the longest convergence time, while the GREC-PPP only needs several minutes to obtain a centimeter-level position accuracy.