3D automatic detection and correction for phase unwrapping errors in time series SAR interferometry

Phase unwrapping (PhU) is one of the most critical steps in synthetic aperture radar interferometry (InSAR) technology. However, the current phase unwrapping methods cannot completely avoid the PhU errors, particularly in complex environments with low coherence. Here, we show that the PhU errors can be corrected well with the time series interferograms. We propose a three-dimensional automatic detection and correction (3D-ADAC) method based on phase closure for time-series InSAR PhU errors to improve the quality of the interferograms, especially for the regions with the same errors in different interferograms which cancel each other out in phase closure. The 3D-ADAC algorithm was evaluated with 26 Sentinel-1 SAR images and 72 phase closure loops over the Tianjin region, China, and compared with the popular MintPy and CorPhU methods. Our results demonstrate that the number of new arcs with model coherence coefficient greater than 0.7 achieved by the proposed method is 2.36 times that by the method used in the MintPy software and 3.07 times that by the CorPhU method. The corrected and improved interferograms will be helpful for accurately mapping the ground deformations or Earth topographies via InSAR technology. Codes and data are available at https://github.com/Lylionaurora/code3d-ADCD.