## 5 Conclusions  
From the perspective of ISAC, this paper has explored the feasibility of detecting ground millimeter-level deformation using CBSs based on D-InSAR technology for the first time, including conducting outdoor experiments to validate this method. The experimental results demonstrate that the phase of the echo signal exhibits significant changes with each movement of the corner reflector, allowing for the precise calculation of the corresponding LOS deformation values based on these phase changes. The LOS deformation trends detected by the CBS closely align with the actual trends, with a maximum error of only 0.3437 mm, thereby confirming the feasibility and accuracy of CBSs in millimeter-level deformation detection. This study has validated the feasibility of utilizing CBSs in conjunction with D-InSAR technology for ground deformation detection, but this novel detection approach still encounters several practical challenges. Firstly, CBSs are susceptible to wind-induced vibrations, which can significantly impact deformation detection accuracy; therefore, the development of corresponding calibration algorithms is necessary. Secondly, in long-term deformation monitoring tasks, atmospheric effects cannot be overlooked, making accurate atmospheric phase correction an essential future task. Lastly, the limited observational range of CBSs necessitates the exploration of multi-CBSs cooperative observation techniques to facilitate larger-scale deformation monitoring efforts. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Characteristic** & **CBSs** & **Satellite SAR Platforms** & **GB-SAR Platforms** \\ \hline
**Cost** & Low & Extreme & High \\ \hline
**Flexibility** & High & Low & Medium \\ \hline
**Scalability** & High & Low & Medium \\ \hline
**Temporal Sampling Rate** & Extreme & Low & High \\ \hline
**Temporal Decorrelation** & Slight & Severe & Moderate \\ \hline
**Observation Range** & Moderate & Extensive & Moderate \\ \hline
**Accuracy** & High & Moderate & High \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison of CBSs, satellite SAR platforms, and GB-SAR platforms. In the future, as the deep integration of CBSs and D-InSAR technology, this method is expected to be applied in areas such as monitoring the subsidence of urban buildings, assessing the health of roads and bridges, and managing traffic in smart cities. Furthermore, this technology can be integrated with currently popular artificial intelligence and big data techniques, thereby enhancing data processing capabilities and establishing a multidimensional perception system. Simultaneously, with the proliferation of 5G or 6 th-Generation (6G) communication networks and the increasing density of CBSs, CBSs are anticipated to become a vital component of urban sensing networks as GB-SAR platforms. In conclusion, this study lays the groundwork for the application of CBSs in ground deformation monitoring and highlights the vast potential of ISAC technology for future developments. As technology continues to advance and applications deepen, CBSs are poised to become a vital tool for efficient, real-time deformation monitoring, contributing positively to societal sustainability and safety. Conceptualization, J.T. ; methodology, J.X., Z.S. and J.T. ; validation, J.X. and Z.S. ; formal analysis, Z.S. ; investigation, J.X. ; writing--original draft preparation, J.X. ; writing--review and editing, Z.S. ; and project administration, Z.S. All authors have read and agreed to the published version of the manuscript. This research received no external funding. The data presented in this study are available on request from the corresponding author due to privacy. Special thanks to Huawei Technologies Co., Ltd. for providing us with valuable experimental resources and conditions, which enabled this experiment to proceed smoothly. At the same time, we would like to express our special thanks to [PERSON] from Huawei Technologies Co., Ltd., who has provided us with great assistance in experimental design and data analysis.