InSAR Deformation Monitoring and Analysis of Mining Area Based on Quadtree Filtering

Due to factors such as loss of coherence between repeated SAR acquisitions, the interferograms are often very noisy. The quadtree filter can remove such discrete noise in unwrapped interferograms and obtain clean deformation results. A mining area in Yunnan is investigated, discussing how the minimum division window and the gross error threshold affect the performance of quadtree filtering. The surface deformation time series of the mining area is obtained using Sentinel-1 satellite data from 2019 to 2021. The results show that the mining area has significant surface deformation during our monitoring period, focusing mainly on three regions with both uplift and subsidence. The deformation time series present wave-like variations in the time domain. The maximum incremental subsidence and uplift are up to 67.3 and 79.4 mm in 12 days, respectively. The difference is $\pm 10.9\mathrm{m}\mathrm{m}$ between InSAR and 41 repeated observations from 32 ground-based total stations.