地基大视场SAR形变监测的非均匀大气相位校正方法

大气变化是地基干涉合成孔径雷达(GB-InSAR)形变监测的主要干扰因素。由于监测环境的地形复杂，水汽、湿度和温度的空间异质性，基于均匀大气介质假设的校正方法可能导致大气校正精度较低。该文提出了一种两阶段半经验模型，用于估计和校正复杂大气条件下特大滑坡GB-InSAR监测过程中出现的大气相位误差。该方法兼顾线性大气相位和非线性大气相位，首先根据测区的范围和高程对观测到的大气相位进行建模，校正与地形相关的线性大气相位。然后，考虑复杂大气条件和方位向大视场角度场景下出现的空间域非均匀大气情况，选取稳定永久散射体(PS)通过插值的方式获取所有PS点的大气相位，校正非线性大气相位。采用该方法对三峡库区新铺和藕塘特大滑坡的地基大视场雷达图像进行处理，相比于常规方法减小大气相位误差最大约2 mm。能有效校正特大滑坡监测场景下出现的非均匀大气相位，满足特大滑坡广域范围监测需求。 

A Non-homogenous Atmospheric Compensation Method for Deformation Monitoring of Wide-field Ground-based SAR

Atmospheric influence is the main interference factor in Ground-Based Interferometric Synthetic Aperture Radar (GB-InSAR) deformation monitoring. Due to the complex terrain and various environmental factors, the correction method based on the assumption of a uniform atmospheric influence may lead to low atmospheric correction accuracy. In this paper, a two-stage semi-empirical model is proposed to correct the atmospheric phase screen during the GB-InSAR monitoring of a super large slope under complex atmospheric conditions. First, the observed atmospheric phase is modeled according to the height and range of the terrain structure to correct the linear atmospheric phase. Then, considering the complex atmospheric conditions and the spatially nonuniform atmosphere with a large azimuth field of view, stable Persistent Scatterers (PS) are selected to obtain the atmospheric phase of all PS by interpolation to correct the nonlinear atmospheric phase. This method is used to process a large field of view radar image of the foundation of the Xinpu and Outang landslides in the Three Gorges Reservoir area. Compared with the conventional method, the atmospheric phase error is reduced by approximately 2 mm. This method effectively corrects the nonuniform atmospheric phase under the landslide monitoring scene and meets the wide-area monitoring needs of the landslide.