Robust differential interferometric synthetic aperture radar deformation phase estimation method based on covariance matrix information of multiple pixels

Differential interferometric synthetic aperture radar (D-InSAR) is a powerful technique to detect ground deformation, and the deformation estimation accuracy is directly affected by the D-InSAR phase accuracy. Coregistration of synthetic aperture radar (SAR) images and/or interferograms is one of the key steps in the D-InSAR flowchart, and the coregistration errors inevitable between SAR images will greatly decrease the D-InSAR phase estimation accuracy. In this study, the authors propose a robust approach to estimate the deformation phase by using the central pixel and its neighbouring pixels simultaneously, which is coupled with the signal subspace fitting or the covariance matrix fitting. The method can accomplish image auto-coregistration and suppress the D-InSAR phase noise together. Furthermore, compared with the required coregistration accuracy (no less than 1/10 pixel) for the conventional D-InSAR processing, the required image and/or interferogram coregistration error of the proposed method can reach 1 pixel, which greatly releases the district limitation on coregistration in D-InSAR processing. The performance is investigated by using simulated data and real ENVISAT ASAR data.