Influence of GW Filter Parameters on the Accuracy of Landslide Displacement Measurements by SAR Interferograms : A Comparative Study with GNSS Positionings around Kounai Area, Sobetsu Town, Hokkaido

Abstract

  The Goldstein-Werner (GW) filter is widely utilized to mitigate phase noise in interferometric synthetic aperture radar (InSAR)-based measurements of landslide displacement. In this study, we investigate the relationship between the parameter settings of the GW filter and the measurement accuracy of SAR interferograms, based on a comparative analysis with GNSS positioning data. The results reveal that inadequate optimization of both the moving window size and the spectral exponent can lead to systematic underestimation of landslide displacements. Furthermore, we empirically demonstrate that the Baran filter, an enhanced version of the GW filter, effectively reduces the number of parameters requiring calibration to the moving window size alone. These results highlight the importance of optimizing filter parameters for phase noise reduction.