## 5 Conclusions  
This work studied the safety monitoring of the ELH Bridge by using the GB-RAR technology during the crossing of the shield tunnel of Wuhan Metro Line 11 underneath the bridge. A GB-RAR deformation information estimation method considering the influence of colored noise was proposed. The accurate settlement monitoring results of the ELH Bridge during the monitoring period are derived by using the proposed estimation method. The main results are as follows:  
1. [label=(0)]
2. White and colored noises were detected in the settlement deformation time series of the No. 7 and 8 piers after denoising by wavelet analysis algorithm, and the colored noise spectral index of each series was estimated to be approximately \(-1\) according to the settlement time series of the No. 7 and 8 piers. 3. The standard deviations of the settlement time series of the No. 7 and 8 piers of the ELH Bridge were 0.19 and 0.18 mm, respectively, indicating that the monitoring accuracy of ground-based interferometric radar was high. The leveling results were used to verify the settlement results obtained by the GB-RAR technology. The root mean square errors of the No. 7 and 8 piers were 0.20 and 0.27 mm, respectively. The results indicate that the GB-RAR technology can effectively and accurately realize the bridge safety monitoring. 4. Affected by various noises, the settlement changes of piers obtained based on the GB-RAR technology show nonlinear settlement. Based on the GB-RAR deformation information estimation method considering the influence of colored noise, the estimated settlement rates of the No. 7 and 8 piers were \(-0.0112\)\(\pm\)\(0.0026\) and \(-0.0046\)\(\pm\)\(0.0053\) mm/h, respectively. The corresponding cumulative settlements were \(-0.40\) mm and \(-0.16\) mm. The cumulative settlements of the No. 7 and 8 piers obtained by the leveling method were \(-0.39\) and \(-0.32\) mm, respectively. The results of the two methods were consistent and satisfied the requirements of safety assessment. During the shield tunneling machine crossing under the ELH Bridge, the cumulative settlement of piers must be less than 1 mm. The method proposed in this paper can be used not only for deformation monitoring and analysis of bridges, but also for deformation monitoring and analysis of other monitoring objects (e.g., super high-rise buildings, dam, and landslide). In the following research work, we will analyze the relationship between GB-RAR deformation time series noise and deformation information, study relevant filtering methods to weaken colored noise, and further improve the reliability of deformation results. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Method**} & \multirow{2}{*}{**Time Span**} & \multicolumn{2}{c}{**Settlement Rates and Uncertainties (mm/h)**} \\ \cline{3-4}  & & **No. 7 Pier** & **No. 8 Pier** \\ \hline GB-RAR Deformation Information & 2016.11.17 & \(-0.0315\pm 0.0053\) & \(-0.0210\pm 0.0085\) \\ Estimation Method Considering the & 2016.11.18 & \(-0.0145\pm 0.0059\) & \(-0.0000\pm 0.0125\) \\ Influence of Colored Noise & 2016.11.17–18 & \(-0.0112\pm 0.0026\) & \(-0.0046\pm 0.0053\) \\ \hline GB-RAR Deformation Information & 2016.11.17 & \(-0.0270\pm 0.0007\) & \(-0.0197\pm 0.0007\) \\ Estimation Method without Considering & 2016.11.18 & \(-0.0099\pm 0.0007\) & \(-0.0007\pm 0.0007\) \\ the Influence of Colored Noise & 2016.11.17–18 & \(-0.0145\pm\ll 10^{-4}\) & \(-0.0013\pm\ll 10^{-4}\) \\ \hline \multirow{2}{*}{Leveling} & 2016.11.17 & \(-0.0055\pm 0.0650\) & \(-0.0140\pm 0.0360\) \\  & 2016.11.18 & \(0.0108\pm 0.0755\) & \(0.0079\pm 0.0408\) \\ \cline{1-1}  & 2016.11.17–18 & \(-0.0107\pm 0.0110\) & \(-0.0089\pm 0.0641\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Settlement deformation rates and rate uncertainties of the piers estimated by the three methods. **Author Contributions:** All authors contributed to the manuscript. [PERSON] and [PERSON] proposed the idea of this work. [PERSON] processed and analyzed the GB-RAR data and contributed to the manuscript.