Iterative Detection and Correction of Unwrapping Errors in SAR Interferometry Based on Phase Closure

Interferometric Synthetic Aperture Radar (InSAR) is commonly used in Earth Sciences to map surface displacement and high-resolution topography. Phase unwrapping is a crucial step in the InSAR data processing. Although there are many methods for phase unwrapping, none of them can completely avoid unwrapping errors. This paper proposes an iterative algorithm to automatically detect and correct unwrapping errors based on interferometric phase closure. This algorithm mainly includes four steps: (i) Find the phase closed loops that all interferograms can form and calculate their closure residuals. (ii) Predict the area to be corrected in the unwrapped interferogram. (iii) The predicted error area is then judged and corrected again. (IV) The above process is repeated iteratively, until all the errors in the interferogram are corrected. This method has been verified in the SAR data and effectively corrects the unwrapping error.