Quantitative Analysis of SAR Image Geometric Distortion and Its Application in Deformation Rate Fusion Mapping

Interferometry synthetic aperture radar (InSAR) technology has emerged as a powerful tool for the early identification and monitoring of geological hazards in the Loess Plateau. Since the SAR satellite adopts the range-azimuth two-dimensional side-looking imaging mode, the corresponding field area of the pixel will change with slope, aspect, and incident angle, especially in areas with severe changes in terrain and landforms, which causes serious area distortion, leading to abnormal deformation rate mapping. Considering the SAR imaging geometry, terrain slope and aspect conditions, this article proposes a quantitative analysis method for accurate geometric distortion (GD) based on pixel area and corresponding field area and constructs a weighted fusion method based on distortion values for InSAR deformation rate maps in overlapping regions of adjacent tracks. Taking Lingtai County, Gansu Province as the research area and sentinel-1 data as the research data, we utilize the SBAS method to process the sentinel-1 data and estimate the deformation rate, and then use the GD value as a weight factor to estimate the fusion rate of the overlapping area of adjacent tracks. The results demonstrate that the weighted fusion method based on distortion values can achieve a high-quality mosaic effect of deformation rate maps of adjacent tracks, effectively improve the GD influence in deformation rate mapping, and the identification of geological hazards.