分布式滑坡形变PSI（永久散射体干涉雷达）监测模型及技术

Landslide is one of distributed objects which are characterized by complex ground features. The point-target based Persistent Scatterer Interferometry (PSI) technique is not applicable to its deformation monitoring. The main objective of this proposal is to develop the state-of-the-art Distributed Persistent Scatterer Interferometry (D-PSI) methodology for an effective landslide deformation monitoring using long-term multi-temporal high resolution SAR data. (1) The issue of distributed landslide object recognition will be firstly addressed from the point of view of physical backscattering mechanism of distribute landslide object. The statistical analysis and fuzzy clustering analysis will be conducted to improve the tempo-spatial interferometric coherent and the signal to noise ratio of the distributed targets in the stack of radar images; (2) The core theory and technology will be studied to develop the Distributed landslide deformation monitoring PSI model (D-PSI) using long time series high resolution SAR images. The precise differential phase caused by deformation will be effectively extracted by means of the integration of point-target and distributed-target based PSI technology which produces more reliable ground scatterers; (3) Finally, cross-validation on D-PSI model based on massive landslide case studies. Iterative work flow will be developed to improve the D-PSI model and attain long term accurate engineering monitoring on landslide deformation.

滑坡是一种具有复杂地表特征的典型分布式目标，基于点目标的永久散射体干涉雷达技术（PSI）对其形变监测存在根本局限性。本项研究着眼于目前国际研究前沿，采用高精度、多时相的雷达数据进行分布式滑坡形变PSI模型（D-PSI）的关键理论和技术研究。主要研究内容和解决的关键科学问题包括： （1）从分布式滑坡目标的雷达散射物理机理出发，采用数理统计和模糊集聚类结合的方法，提高其时空相干信息特征与信噪比, 解决分布式滑坡散射特征分析及目标提取的关键问题；（2）利用长时间序列的高精度SAR数据集，进行分布式滑坡形变PSI模型（D-PSI）核心理论和方法研究，建立分布式目标干涉模型和相位模型, 采用分布式散射目标与点散射目标相结合的技术进行精确相位值的分离，提取高密度的分布式滑坡目标形变信息，有效提高滑坡形变监测的精度；（3）通过大量案例研究和交叉验证，切实改进D-PSI模型，实现工程级滑坡监测。

本项目紧密围绕构建分布式滑坡形变PSI（永久散射体干涉雷达）监测模型的若干关键科学和技术问题，综合利用理论推导和实例分析等手段开展研究，主要在以下四个方面的研究内容上取得了研究成果：1）完成了分布式滑坡目标后向雷达散射特征分析，获取了分布式滑坡目标区别于点目标和失相干目标的后向雷达散射特征，为提出分布式滑坡目标的提取方法提供了依据；2）基于AD（Anderson-Darling）检验方法识别了分布式目标的同质区域，进而提出了分布式滑坡目标识别与提取方法，为分布式滑坡形变信息反演提供了基础；3）利用最大似然法，分析同质区像元特征，得到每个分布式目标上形变和高程的最优解，实现了分布式滑坡PSI 形变解算模型（D-PSI）的构建；4）将构建的分布式滑坡形变PSI模型应用到了川藏联网工程等多处滑坡形变监测和灾害风险评估中，实现了工程级滑坡监测的案例应用。本项目按照既定计划实施执行，并完成了既定研究目标。