 This paper examines the land subsidence in Beijing, China, caused by excessive groundwater extraction over the last three decades. To do so, they use time series in SAR data collected by Gaofan, three SAR satellites. They compare their findings with those obtained using Sentinel-1 SAR data, which was also used to evaluate the accuracy of Gaofan, three data. Their results show that the subsidence rate has decreased since 2020, but it still remains significant. Additionally, they found that the subsidence rate is higher in areas where there is more groundwater extraction. Furthermore, they identified the main factors that affect the quality of the interferograms produced by Gaofan, three SAR data, such as the long perpendicular baseline and errors in the orbit information. By refining and removing these artifacts, they were able to improve the quality of the interferograms. This article was authored by Yakan Han, Tao Li, Karen Dai, and others.