Evaluation of PS-DInSAR technology for subsidence monitoring caused by repeated mining in mountainous area

The high resolution TerraSAR-X dataset was employed with DInSAR and persistent scatterer interferometry (PSI) technique for subsidence monitoring in a mountainous area. For DInSAR technique, the generally used SRTM and relief-DEM, which was derived from aerial topographic map, were used to evaluate the influence of external DEM. The results show that SRTM could not fully compensate the complex topography of the research area. The corner reflectors installed during the acquisition of SAR dataset were used to estimate the accuracy of geocoding. The terrain corrected geocoding results based on relief-DEM were much better than using SRTM, with the root mean square error (RMSE) being 6.35 m in X direction and 11.65 m in Y direction (both in UTM projection), around one pixel of the multilooked intensity image to be geocoded. For PSI technique, the results from time-series analysis of multi-baseline differential interferograms were integrated to restrict only persistent scatterer candidates near the boundary of subsiding area for regression analysis. The results demonstrate that PSI can refine the boundary of subsidence, which could then be used to derive some angular parameters to help people to learn the law of subsidence caused by repeated excavation in this area.