## 2 Arc Synthetic Aperture Radar  
ArcSAR (Arc Synthetic Aperture Radar) is a radar system that utilizes arcuate motion to achieve high-resolution imaging. Its working principle is based on the fundamental concept of Synthetic Aperture Radar (SAR), which simulates the effect of a large physical antenna aperture to obtain high-resolution ground images using a smaller actual antenna size. The uniqueness of ArcSAR lies in its arcuate path of motion, where the radar employs a long rotating boom to swing, enabling the low-gain antenna at the end of the boom to move along an arcuate trajectory. By synthesizing high-resolution imaging beams along this arcuate trajectory, ArcSAR is able to cover a large monitoring area in a short period of time, thereby enhancing monitoring efficiency and flexibility.  
A picture of the field operation of the ArcSAR arcuate Synthetic Aperture Radar equipment is shown in Figure 1. The hardware performance parameters of the ArcSAR radar are shown in Table 1.  
The ArcSAR radar monitoring data display and interaction platform adopt a B/S (browser/Server) architecture, allowing users to access the application by simply opening a web browser and entering the website address. It is cross-platform compatible, meaning that users can access real-time monitoring data anytime, anywhere, using desktop computers, laptops, tablets, or mobile phones. This greatly enhances the convenience of using the  
\begin{table}
\begin{tabular}{c c} \hline
**Parameter Name** & **Parameter** \\ \hline spatial resolution reaching & \(\Delta\)R 0.3 m \(\times\)\(\Delta\)Az 5 mrad \\ monitoring distance exceeding & 5 km \\ deformation accuracy & 0.1 mm \\ coverage area & 360\({}^{\circ}\)\(\times\) 30\({}^{\circ}\) \\ length, width, and height & 1.33 m \(\times\) 0.42 m \(\times\) 0.63 m \\ \hline scanning period & 0.5 to 4 min (configurable) \\ \hline \end{tabular}
\end{table}
Table 1: Parameters of Arc Synthetic Aperture Radar equipment.  
Figure 1: Arc Synthetic Aperture Radar system (commercial product).  
radar product. The platform provides radar monitoring data scatter plots (intensity maps), which can be processed through interferometry to generate deformation maps. Users can quickly locate dangerous slope areas through the deformation maps.  
The software platform supports map import functionality, allowing the import of three-dimensional topographic maps of opencast mine slopes captured by drone aerial photography into the radar monitoring platform for three-dimensional registration, as shown in Figure 2. Additionally, observation points can be manually set on the topographic map, and the system will automatically calculate displacement change data, velocity change data, acceleration change data, and reciprocal velocity change data for each observation point. Compared to GNSS monitoring technology, ArcSAR radar monitoring technology offers advantages such as non-contact, high sampling rate, high precision, and overall regional monitoring. While ArcSAR radar monitoring technology offers numerous advantages, it is important to note its limitations, particularly in terms of the high cost, data processing complexity, and high maintenance difficulty involved in using the equipment.