An Improved Method for Topography-Related Tropospheric Delay Modeling Using Adaptive Window

An improved synthetic aperture radar interferometry (InSAR)-based method for modeling and mitigating the topography-related tropospheric delay by adaptively selecting appropriate window is proposed in this article. It adopts a coarse search and then a refined binary search to determine the optimal window size for each pixel. Moreover, the correlation between stratified delay and topography is estimated within the local window centered on the target pixel, the size of which is the determined optimal value. Compared with the traditional approaches (i.e., the predefined windows and sliding windows with fixed sizes), the novelty of the proposed method lies in three aspects: 1) the optimal window for each pixel can be adaptively determined based on the elevation gradient through a coarse-to-refined search, 2) reliable correlation information between neighboring pixels is fully exploit without imposing artificial spatial boundaries, and 3) the correlation between topography-related tropospheric delay and elevation estimated from neighboring sub-windows is spatially consistent. The effectiveness of the proposed method is validated through a series of simulated datasets and real Sentinel-1A experiments over the Hawaii region. The results indicate that our approach enables to better correct the topography-related tropospheric delay in interferograms and improve the accuracy of InSAR-based deformation monitoring.