PS-DInSAR技术在山区重复采动地表沉陷监测中的应用

摘要

基于高分辨率TerraSAR-X数据，利用DInSAR和PSI技术监测山区重复采动引起的地表沉陷。在 DInSAR数据处理过程中，分别利用SRTM、基于矿区大比例尺航测地形图生成的relief-DEM对外部DEM的影响进行分析评价。结果表明，由于研究区的地形复杂，SRTM无法充分补偿地形相位。随后，利用在矿区范围内布设的角反射器对基于不同外部DEM的地理编码进行检验，结果显示，基于relief-DEM的地理编码精度明显较优，其在X、Y方向的地理编码中误差分别为6.35 m和11.65 m。对于PSI技术，为了降低形变梯度过大对相位解缠的影响，基于时序DInSAR的处理结果，对识别出来的PS点进行掩模，使得只有位于沉陷边缘和稳定区域的PS点用于PSI分析处理。结果表明，PSI技术可以进一步优化时序DInSAR获取的地表形变边界信息。%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 inX direction and 11.65 m inY 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.