ABSTRACT

Persistent scatterer interferometry (PSI) has been proved to be an advanced Interferometric Synthetic Aperture Radar (InSAR) technique used to measure and monitor terrain deformation. Two of the critical problems with InSAR have been the effect of the refractive atmosphere and decorrelation on the interferometric phases due to long spatial-temporal baseline. The low density of persistent scatterers (PS) in non-urban areas affected by spatial-temporal decoherence more seriously has inspired the development of alternative approaches. Sentinel-1 (S1) has improved the data acquisition throughout, and compared to previous sensors, increased considerably the differential interferometric SAR (DInSAR) and PSI deformation monitoring potential. This paper describes an innovative methodology to process S1 SAR data. Different with PSI, its most original part includes two key processing stages: high and low frequency splitting from wrapped phases, prior to atmospheric filtering, and final direct integration to generate the complete deformation with time series containing linear and nonlinear components. The proposed method has two fundamental advantages compared with traditional PSI approach: the final monitoring results with excellent coverage of coherent points and the generation of active maps even for the areas with serious deformation in short term to break through the inherent limitation of PSI. The effectiveness of the proposed tools is illustrated using a case study located in Catalonia (Spain). This methodology has supposed a definitive step towards the implementation of DInSAR based techniques to support decision makers against geohazards. In this work, the deformation procedures happened in three different areas of the Catalonia (Spain) are presented and analysed. The maximum accumulated subsidence of over – 60 cm induced by mining activity can be detected by proposed methodology with nice coverage from January 2017 to January 2019. These reported cases illustrate how DInSAR based techniques can provide detailed terrain deformation for geohazard activity with complex topographical conditions. The active deformation areas map can be generated in fast aimed at geohazard risk early warning and management.

摘要

持久散射体干涉测量 (PSI) 已被证明是一种先进的干涉合成孔径雷达 (InSAR) 技术，用于测量和监测地形变形。InSAR 的两个关键问题是折射大气和去相关对干涉相位的影响，这是由于长时空基线造成的。受时空退相干影响更严重的非城市地区持久性散射体 (PS) 的低密度激发了替代方法的发展。Sentinel-1 (S1) 改进了整个数据采集，与以前的传感器相比，显着增加了差分干涉 SAR (DInSAR) 和 PSI 变形监测潜力。本文描述了一种处理 S1 SAR 数据的创新方法。与PSI不同，它最原始的部分包括两个关键处理阶段：在大气滤波之前从包裹相位分离高频和低频，以及最终直接积分以生成包含线性和非线性分量的时间序列的完整变形。与传统PSI方法相比，所提出的方法具有两个根本优势：最终监测结果具有良好的相干点覆盖和即使是短期内变形严重的区域也能生成活动图，突破了PSI的固有局限性。使用位于加泰罗尼亚（西班牙）的案例研究说明了所提议工具的有效性。这种方法被认为是实现基于 DInSAR 的技术以支持决策者应对地质灾害的决定性步骤。在这项工作中，介绍和分析了加泰罗尼亚（西班牙）三个不同地区发生的变形过程。从 2017 年 1 月到 2019 年 1 月，通过具有良好覆盖范围的拟议方法可以检测到采矿活动引起的超过 – 60 厘米的最大累积沉降。这些报告的案例说明了基于 DInSAR 的技术如何为具有复杂地形条件的地质灾害活动提供详细的地形变形。可快速生成活动变形区图，用于地质灾害风险预警和管理。这些报告的案例说明了基于 DInSAR 的技术如何为具有复杂地形条件的地质灾害活动提供详细的地形变形。可快速生成活动变形区图，用于地质灾害风险预警和管理。这些报告的案例说明了基于 DInSAR 的技术如何为具有复杂地形条件的地质灾害活动提供详细的地形变形。可快速生成活动变形区图，用于地质灾害风险预警和管理。