## 3 Results
### Closure Error  
Analyzing the data on 1 March 2022, it can be seen that there are 226 inter-satellite station closure errors and 1710 three-satellite closure errors concerning 27 satellites. Some inter-satellite station closure errors and three-satellite closure errors are detailed in Table 3, and statistical results of all closure errors are itemized in Table 4.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Satellite**} & **Only SGL** & \multirow{2}{*}{**SGL+ISL Method**} & \multirow{2}{*}{**WNA Method**} & **Improvement Rate 1** & \multirow{2}{*}{\begin{tabular}{c} **Improvement Rate 2** \\ **(WNA Relative to** \\ **SGL+ISL)** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Improvement Rate 1** \\ **(WNA Relative to** \\ **SGL+ISL)** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Improvement Rate 2** \\ **(WNA Relative to** \\ **SGL+ISL)** \\ \end{tabular} } \\ \cline{1-1}  & **Method** & & & & **Only SGL** & **SGL+ISL** \\ \hline C38 & 0.60 & 0.49 & 0.29 & 51.67\% & 40.82\% \\ C39 & 0.40 & 0.40 & 0.28 & 30.00\% & 30.00\% \\ C40 & 0.48 & 0.43 & 0.19 & 60.42\% & 55.92\% \\ C25 & 0.67 & 0.51 & 0.27 & 59.70\% & 47.06\% \\ C26 & 0.48 & 0.37 & 0.27 & 43.75\% & 27.03\% \\ C27 & 0.77 & 0.57 & 0.24 & 68.83\% & 57.89\% \\ C28 & 0.54 & 0.46 & 0.15 & 72.22\% & 67.39\% \\ C29 & 0.68 & 0.50 & 0.26 & 61.76\% & 48\% \\ C30 & 1.12 & 0.91 & 0.23 & 79.46\% & 74.73\% \\ C19 & 0.80 & 0.68 & 0.23 & 71.25\% & 66.18\% \\ C20 & 0.60 & 0.48 & 0.22 & 63.33\% & 54.17\% \\ C21 & 0.59 & 0.51 & 0.26 & 55.93\% & 49.02\% \\ C22 & 0.68 & 0.48 & 0.29 & 57.35\% & 39.58\% \\ C23 & 0.87 & 0.63 & 0.33 & 62.07\% & 47.62\% \\ C24 & 0.50 & 0.49 & 0.23 & 54.00\% & 53.10\% \\ C32 & 0.76 & 0.65 & 0.28 & 63.16\% & 56.86\% \\ C33 & 0.84 & 0.96 & 0.34 & 59.52\% & 64.64\% \\ C34 & 1.25 & 0.49 & 0.20 & 84.00\% & 59.18\% \\ C35 & 0.33 & 0.32 & 0.19 & 42.42\% & 40.63\% \\ C36 & 0.66 & 0.73 & 0.26 & 60.61\% & 64.38\% \\ C37 & 0.91 & 0.51 & 0.22 & 75.82\% & 56.86\% \\ C41 & 0.49 & 0.42 & 0.20 & 59.18\% & 52.38\% \\ C42 & 0.45 & 0.33 & 0.21 & 53.33\% & 36.36\% \\ C43 & 0.57 & 0.59 & 0.21 & 63.16\% & 64.41\% \\ C44 & 1.66 & 0.98 & 0.43 & 74.10\% & 56.12\% \\ C45 & 0.69 & 0.45 & 0.22 & 68.12\% & 51.11\% \\ C46 & 0.97 & 0.32 & 0.17 & 82.47\% & 46.88\% \\ Mean & 0.72 & 0.54 & 0.25 & 62.13\% & 52.15\% \\ \hline \hline \end{tabular}
\end{table}
Table 2: RMS statistical results of prediction error (unit: ns).  
It can be seen from Tables 3 and 4, among 226 inter-satellite station closure errors and 1710 three-satellite closure errors, the closure error of inter-satellite station and three-satellite of \"one-hop\" reduction method are 0.69 ns and 0.23 ns, respectively. In addition, the closure error of the whole-network adjustment method is 1.34 \(\times\) 10\({}^{-10}\) and 5.54 \(\times\) 10\({}^{-11}\), respectively, which both approximate 0. The results show that the closure error of inter-satellite station is subject to SGL reduction, while the closure error of three-satellite is subject to ISL measurement only. Therefore, three-satellite closure error is superior to the inter-satellite closure error, indirectly indicating that the SGL measurement error is a limiting factor that improves in the system time synchronization accuracy.