# Earth Rotation Parameters Estimation Using GPS and SLR Measurements to Multiple LEO Satellites
## 3 ERP Estimation Based on the Single LEO Satellite
### ERP Estimation with Different LEO Satellites
These results illustrate that the accuracy of station coordinates are more sensitive to the \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Satellite**} & \multicolumn{2}{c}{**X Pole (ms)**} & \multicolumn{2}{c}{**Y Pole (ms)**} & \multicolumn{2}{c}{**LOD (ms)**} \\ \cline{2-7}  & **Mean** & **RMS** & **Mean** & **RMS** & **Mean** & **RMS** \\ \hline GRACE-C & \(-0.1694\) & \(2.0062\) & \(0.0043\) & \(1.8425\) & \(-0.0050\) & \(0.0650\) \\ \hline GRACE-D & \(-0.0622\) & \(2.3469\) & \(0.1280\) & \(1.8840\) & \(0.0018\) & \(00579\) \\ \hline SWARM-A & \(-0.0343\) & \(2.9698\) & \(-0.0413\) & \(2.1253\) & \(-0.0048\) & \(0.0770\) \\ \hline SWARM-B & \(-0.0492\) & \(1.9286\) & \(0.0619\) & \(1.6634\) & \(0.0039\) & \(0.0673\) \\ \hline SWARM-C & \(-0.0932\) & \(2.8565\) & \(-0.0519\) & \(1.9805\) & \(0.0139\) & \(0.0719\) \\ \hline SENTINEL-3A & \(0.0636\) & \(2.7018\) & \(-0.0757\) & \(2.1211\) & \(-0.0178\) & \(0.0675\) \\ \hline SENTINEL-3B & \(-0.0137\) & \(3.1221\) & \(-0.0012\) & \(2.1866\) & \(-0.0287\) & \(0.0829\) \\ \hline LAGEOS & \(-0.0475\) & \(1.0686\) & \(0.0871\) & \(0.9449\) & \(-0.0088\) & \(0.0424\) \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Mean biases and RMS values of pole coordinates and the length-of-day in seven single-LEO satellite solutions and LAGEOS satellite solution w.r.t the finals2000A_data series. Figure 4: Spectral analysis for GRACE-C, Sentinel-3A, LAGEOS (LAGEOS-1 and LAGEOS-2), Swarm-C and Swarm-B solutions. quality of the LEO orbit, under the condition that enough SLR observations to the LEO satellite can be obtained. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Station**} & \multirow{2}{*}{**Satellite**} & \multicolumn{2}{c}{**E (mm)**} & \multicolumn{2}{c}{**N (mm)**} & \multicolumn{2}{c}{**U (mm)**} \\ \cline{3-8}  & & **Median** & **IQR** & **Median** & **IQR** & **Median** & **IQR** \\ \hline \multirow{8}{*}{All stations} & GRACE-C & \(0.6\) & \(19.0\) & \(1.3\) & \(21.2\) & \(0.7\) & \(16.8\) \\ \cline{2-8}  & GRACE-D & \(-0.2\) & \(16.6\) & \(1.0\) & \(20.5\) & \(2.6\) & \(14.7\) \\ \cline{2-8}  & SWARM-A & \(0.6\) & \(17.3\) & \(0.9\) & \(26.7\) & \(4.8\) & \(19.8\) \\ \cline{2-8}  & SWARM-B & \(-2.4\) & \(29.4\) & \(-0.1\) & \(22.6\) & \(7.7\) & \(23.7\) \\ \cline{2-8}  & SWARM-C & \(-3.6\) & \(24.0\) & \(-0.3\) & \(28.9\) & \(4.6\) & \(21.1\) \\ \cline{2-8}  & SENTINEL-3A & \(7.1\) & \(21.8\) & \(-0.3\) & \(21.8\) & \(-3.0\) & \(14.1\) \\ \cline{2-8}  & SENTINEL-3B & \(10.5\) & \(32.4\) & \(-0.1\) & \(26.5\) & \(-0.2\) & \(21.8\) \\ \cline{2-8}  & LAGEOS & \(1.2\) & \(23.1\) & \(-4.9\) & \(25.6\) & \(-5.6\) & \(24.9\) \\ \hline \multirow{8}{*}{Core stations} & GRACE-C & \(0.4\) & \(14.2\) & \(0.5\) & \(21.1\) & \(-1.0\) & \(11.1\) \\ \cline{2-8}  & GRACE-D & \(-0.1\) & \(14.9\) & \(-0.6\) & \(19.6\) & \(-0.5\) & \(10.8\) \\ \cline{2-8}  & SWARM-A & \(-0.3\) & \(16.9\) & \(-0.8\) & \(23.9\) & \(5.1\) & \(16.7\) \\ \cline{2-8}  & SWARM-B & \(-1.5\) & \(24.8\) & \(-0.8\) & \(22.1\) & \(5.0\) & \(16.8\) \\ \cline{2-8}  & SWARM-C & \(-6.6\) & \(18.8\) & \(1.7\) & \(30.2\) & \(2.2\) & \(15.3\) \\ \cline{2-8}  & SENTINEL-3A & \(6.2\) & \(16.3\) & \(0.9\) & \(20.5\) & \(-3.9\) & \(10.7\) \\ \cline{2-8}  & SENTINEL-3B & \(9.0\) & \(27.4\) & \(2.2\) & \(27.3\) & \(-3.0\) & \(16.7\) \\ \cline{2-8}  & LAGEOS & \(0.2\) & \(14.4\) & \(-1.6\) & \(19.0\) & \(-4.3\) & \(14.5\) \\ \hline \end{tabular}
\end{table} 
Table 8: Differences in estimated SLR station coordinates w.r.t. SLRF2014 in seven single-LEO satellite solution and LAGEOS satellite solution decomposed into E, N, U components. Figure 5: Differences of all SLR station and core station coordinates w.r.t. SLRF2014. As shown in Table 8, the LAGEOS solution achieves a station coordinate with worse accuracy than some single-LEO solutions, such as GRACE-C, GRACE-D and Sentinel-3A solutions, when considering all the SLR stations.