用PSInSAR技术监测地面沉降研究

MONITORING GROUND SUBSIDENCE WITH PERMANENT SCATTERERS INTERFEROMETRY

永久散射体差分干涉测量技术为提高形变监测精度展示了很好的应用前景。根据ERS1/2卫星提供的InSAR数据,采用三重阈值PS自动探测算法,获取了1992—2002年上海试验区的地表沉降,上海试验区的总体平均沉降速率为9.3mm/a,与精密水准测量结果具有较高的一致性。

PSInSAR makes it possible to overcome both phase decorrelations and atmospheric delays, and shows a properous future for improving the accuracy of monitoring crustal movement. However, the key steps for the data processing are not well developed such as PS detection, network construction and model estimation. Therefore, a three-thresholding algorithm i. e. , a method to serially execute correlation-coefficient thresholding, amplitude dispersion index thresholding and amplitude index thresholding is proposed and implemented to improve the quality of PS detection. In addition, a method with tree-structure is proposed to estimate the PS absolute terrain error and linear velocity of deformation. Finally, a case study in Shanghai experimental area is finished. The InSAR data sets from ERS1/2 and the new method proposed are utilized to successfully dectect the PS points and obtain the subsidence during the period from 1992 to 2002, that the regionally average value of the subsidence is 9.3 mm/a. The new results are basically in accordance with that from the levelling.