## 4 Results and Discussion
### Analysis of Differential Interferometric Effects  
In Figure 8, the time-series differential interferograms for the \"Fucheng-1\" and \"Shenqi\" satellites, derived from the stacked intensity images, are compared with the Sentinel-1A differential interferograms. Due to its higher resolution, the interferometric performance of the \"Fucheng-1\" and \"Shenqi\" dual-star constellations is exceptional, with the differential interferograms exhibiting smooth and continuous phase variations. Except for the mining areas, where phase changes are more pronounced, the phase variations remain stable, and the interferometric capability is consistent over a long temporal baseline. Using the \"Fucheng-1\" image from 22 January 2025 as the reference master image and the \"Shenqi\" image from 21 November 2024, with a 62-day temporal baseline, we conducted detailed monitoring for five mining areas in the Jinchuan mining district, taking advantage of the satellite's high resolution. Figure 9 presents the differential interferometric effects from the dual-satellite constellation. The interferometric fringes are visible in the mining areas, and the deformation patterns are evident in the differential interferograms. Upon analyzing the interferometric fringes, it can be observed that the deformation in the P1, P2, and P5 mining areas is relatively small, while the P3 and P4 areas show significant  
Figure 7: (**a**–**c**) Coherence coefficient distribution of “Fucheng-1”/”ShenQi” using the same master image, 2025012, and different slave images: (**a**) 20250111, (**b**) 20250311, and (**c**) 20241026. (**d**–**f**) Coherence coefficient distribution of Sentinel-1A using the same master image, 20250118, and different slave images: (**d**) 20250106, (**e**) 20250307, and (**f**) 20241026.  
deformation. In particular, the P4 mining area exhibits dense interferometric fringes over a 2-month span, suggesting a deformation of over 10 cm. Subsequently. TS-InSAR technology will be used for deformation monitoring and the analysis of mining activities in areas P1 to P5. Beyond the visual assessment of differential interferograms, in this paper, we implement two quantitative evaluation metrics--SPD and PSD--to objectively compare the interferometric performance between the dual-star constellation and Sentinel-1A. The SPD  
Figure 8: (**a**–**c**) Interferogram behavior of “Fucheng-1”/”ShenQi” using the same master image, 20250122, and different slave images: (**a**) 20250111, (**b**) 20250311, and (**c**) 20241026. (**d**–**f**) Interferogram behavior of Sentinel-1A using the same master image, 20250118, and different slave images: (**d**) 20250106, (**e**) 20250307, and (**f**) 20241026. For clearer viewing, the Sentinel-1A interferogram has been processed using multi-look 4:1 (range: azimuth) and the dual-star constellation has been processed using multi-look 4:4. Figure 9: (**a**) Differential interferogram of the “Fucheng-1” and “Shenqi” dual-star constellation over the mining area, showing five mining sites (P1–P5); more fringes indicate a more intensive deformation magnitude, and the P4 center area suffers from decorrelation due to excessive deformation. (**b**) Google Earth image of the Jinchuan mining area in Jinchang. quantifies the phase deviation between central pixels and their eight neighbors [32], while PSD measures phase smoothness across local regions or entire images [33]. In theory, lower SPD and PSD values indicate better phase smoothness, and as shown in Figure 10, account for resolution differences between the Sentinel-1A and \"Fucheng-1\"/\"ShenQi\" systems, even when the overlapping study area covers 172.01 km\({}^{2}\), leading to significant differences in interferogram dimensions. Consequently, in this study, we employed the mean values for both the SPD and PSD metrics to comparatively evaluate the quality of interferograms generated by the dual-satellite constellation and Sentinel-1A.