A Compensation Method of Nonlinear Atmospheric Phase Applied for GB-InSAR Images

When the Permanent Scatterer (PS) technique is utilized to compensate the Atmospheric Phase (AP) for Ground-Based Interferometric Synthetic Aperture Radar (GB-InSAR) images, a proper parametric model should be built to describe the AP. However, for some interferograms, the AP may nonlinearly vary with the PS range, and this cannot be effectively compensated via the conventional method. This paper proposes an improved method to compensate the nonlinear AP. Here, the conventional method is first used to compensate all the phase interferograms. By calculating the standard deviation of the phase sequence of every PS and setting a proper threshold, a large number of stable PSs are selected. Then these stable PSs are divided into a certain number of sub-regions, and some control points are determined. With the inverse distance weighting interpolation, the APs of all the PSs are estimated and compensated. To verify the effectiveness of the proposed method, 460 radar images are processed, and the results are made compared with those of the conventional method. The nonlinear AP could be better compensated with the proposed method to avoid misunderstanding of the motional area. Several reference PSs are selected to make quantitative comparisons, and measurement error up to 1 rad could be reduced.