Filtering of the Atmospheric Phase Screen in InSAR Data Using the Nonequispaced Fast Fourier Transform

This work addresses the problem of estimating and filtering the Atmospheric Phase Screen from a stack of image phases, extracted from a sequence of SAR images using the PSInSAR approach. Leveraging the assumption that the atmospheric disturbance is a signal with a high spatial correlation and low temporal correlation, a Nonequispaced FFT is used to estimate the spatial spectrum of the input data, which are distributed spatially on a non-uniform grid, then perform a lowpass filter, followed by a highpass temporal filter. The obtained APS estimate is then removed from the input data. The performance of the proposed method is evaluated over Sentinel-1 SAR data to study mining-induced terrain deformations in the Polkovice area, Poland.