基于时序干涉SAR的地下核试验形变监测关键技术研究

For the potential safety issues brought by underground nuclear tests around China, theoretical research and experimental analysis are used to solve the key technologies for the underground nuclear test deformation monitoring based on the time-series synthetic aperture radar interferometry (TSInSAR). Aiming at the geographical environment characteristics of underground nuclear test sites such as mountainous area, vegetation coverage, and coastal area, the key technologies such as Joint-Scatterer processing, atmospheric correction based on atmospheric numerical model, and nuclear test parameter inversion model were developed. The work will focus on the scientific issues such as the goodness-of-fit test based on the statistical characteristics of joint scatterers, and the optimization of TSInSAR processing flow based on the WRF model, in order to solve the problem of the traditional TSInSAR technology to obtain a sufficient number of permanent scatterers under the complex geographical condition. The work will solve the technical difficulties in underground nuclear test deformation monitoring by TSInSAR based on the WRF model. Through the research of this topic, it is expected to propose a series of programs and procedures for TSInSAR in complex geographical conditions, so as to achieve the efficient and accurate assessment of surface deformation in underground nuclear tests areas and inversion of nuclear test parameters.

针对地下核试验对我国带来的潜在重大安全问题，通过理论研究和实验分析，解决基于时序干涉SAR监测地下核试验形变中的关键技术。针对地下核试验场山区、多植被覆盖、临海等地理环境特点，开展基于联合像素的预处理技术、基于大气数值模式的大气校正、核试验参数反演模型等关键技术研究。重点研究基于联合像素统计特性的拟合优度检验问题、基于WRF模式的时序干涉处理流程优化等科学问题。解决传统时序干涉SAR技术在该地理环境条件下难以得到数量足够的有效永久散射体的问题，基于WRF模式改进现有的时序干涉SAR处理流程，解决将时序干涉SAR技术应用于地下核试验形变监测的技术难点。通过本课题的研究可望提出一套适应于山区、植被覆盖、临海等复杂地理环境下的时序干涉SAR处理方案和流程，实现对地下核试验重点区域地表形变的高效正确评估及核试验参数反演。

本项目针对地下核试验场山区、植被覆盖、临海等复杂环境特点，对研究阶段中遇到的数据处理等环节的关键技术进行了研究，开展了时序InSAR预处理、大气校正、相位解缠、三维形变获取等方面的算法研究。首先，针对中低相干性山体形变监测问题，在传统的PSI技术基础上增加预处理的步骤，提出基于分布散射目标的联合像素时序干涉预处理技术，深入分析了三种基于联合像素的优化处理技术；然后，重点针对长波场数据（如ALOS的L波段数据）的电离层效应开展了研究；同时，对时间序列InSAR相位解缠技术进行了优化研究，对升降轨三维形变获取、形变解算效率提升等方面进行了探索；最后，利用研究区域获得的InSAR数据提取了朝鲜丰奚里核试验场不同时期的形变结果。通过项目的研究，深入分析了基于时序InSAR进行复杂区域形变监测中涉及到的关键技术，可以为核试验区域等复杂区域的地表形变高效准确监测提供技术支撑。