## 4 Results and Discussion
### TS-InSAR Deformation Monitoring Results
#### 4.3.3 Comparative Analysis of TS-InSAR Results: \"Fucheng-1\", \"Shenqi\", and Sentinel-1A  
Figure 14 demonstrates that the Tianyi Institute's dual-star constellation, with its shorter revisiting period and higher-spatial-resolution imagery, captures larger deformation magnitudes and higher monitoring point density in the five mining areas compared to Sentinel-1A while maintaining consistent deformation trends, which can enable a more detailed understanding of subsidence in mining areas. During the early observation task, due to the limitations of C-band satellites in rapid deformation monitoring, the \"Fucheng-1\" and \"Shenqi\" satellites had a revisiting period of 11 days, with most of the imagery captured solely by \"Fucheng-1\". After 20 February 2025, the observation density of \"Shenqi\" was increased in this region, leading to deformation trends in the P3 and P4 areas that were consistent with the Sentinel-1A results. P4 is located in the West No. 2 Mining Area of Longshou Mine, which is used for the pillarless sublevel caving mining method [34]. Under the influence of large-scale goat areas and ground pressure, the roof develops cracks and fails, leading to a significant increase in surface  
Figure 12: Local magnification of time-series PS-InSAR and DS-InSAR deformation velocity in the Jinchuan mining area. The left image represents PS-InSAR (**a**), and the right image represents DS-InSAR (**b**). Figure 13: **(a)** Time-series PS-InSAR line-of-sight deformation monitoring results for the Jinchuan mining area based on \"Fucheng-1\" and \"Shenqi\". (**b**) Histogram of the cumulative distribution of time-series PS-InSAR deformation monitoring results. subsidence. In the P4 central mining area, intensive mining activities caused significant deformation, with dense deformation fringes in the interferogram, resulting in an obvious decorrelation. As a result, there were no monitoring points in the internal regions of the mining area, except for the outer part of the mining area. In the P3 mining area, phase unwrapping errors also occurred, but for the P1 and P2 mining areas, the calculation results showed a relatively noticeable improvement compared to the Sentinel-1A time-series results. Backfill mining is employed at P1 and P2 [35,36]. The backfill bears the surrounding rock pressure, and its settlement primarily results from the compression of the backfill and the absence of contact between the backfill and the roof. The deformation magnitude is relatively smaller compared to that for P4. P3 has a mining history spanning several decades and a mining depth exceeding 300 m. The monitoring results are affected by recent intensive underground mining activities, high slope gradients, and severe surface collapse phenomena, specifically in the P2 mining center area, where the Sentinel-1A results exhibit severe decorrelation, resulting in the absence of monitor points and the presence of unwrapping errors. However, based on the \"Fucheng-1\" and \"Shenqi\" satellite data, the maximum deformation rate in the center of this area reached \(-\)115.28 mm/yr, indicating a more accurate and detailed deformation measurement compared to Sentinel-1A. This demonstrates the advantage of using higher spatial resolution datasets from multiple satellites, particularly in regions with moderately intense mining activities where deformation is more significant. The increased observation frequency and the combination of data from different satellites enable better monitoring and more precise deformation rate estimation, especially in challenging areas with phase unwrapping issues. Figure 15 and Table 4 presents the cumulative deformation analysis for the five mining areas P1-P5; the central areas of P3 and P4 are excluded due to decorrelation or phase-unwrapping errors, necessitating the use of the peripheral points G3 and G4 for these regions, while points G1, G2 and G5 are selected in P1, P2 and P5, respectively, based on maximum subsidence rates.