Refinement Analysis of Real Dihedral and Trihedral CR-InSAR Based on TerraSAR-X and Sentinel-1A Images

This study creatively invented a new type of turnbuckle adjustable corner reflector (CR), which greatly enhances the flexible adjustment ability of CR in both vertical and horizontal directions through a unique positive and negative screw structure design, significantly improving the convenience of on-site deployment. Based on the performance of dihedral CR and trihedral CR installed in the South-to-North Water Diversion Channel using back-to-back design on TerraSAR-X and Sentinel-1A images, the performance of different structures of CR in complex environments, especially under heavy precipitation conditions, was deeply analyzed. The experimental results show that the trihedral CR can still maintain stable monitoring efficiency when encountering extreme weather conditions with precipitation exceeding 10 mm. The monitoring effect of traditional dihedral CR drops sharply and is almost ineffective in such environments. At the same time, the combination of theoretical radar cross section (RCS) and measured RCS values confirms the decisive impact of CR geometry and deployment strategy on improving monitoring stability and accuracy. Further precise comparison between CR-InSAR monitoring results and the second-order leveling measurement results shows that the system's average error is controlled within the range of 2–3 mm using trihedral CR. Compared with the results of dihedral CR and InSAR without CR, a significant improvement in accuracy has been achieved. This study provides strong theoretical support and practical guidance for the optimization design and practical application of CR systems, and has important scientific value and application prospects.