An Improvement of Multiple-Aperture SAR Interferometry Performance in the Presence of Complex and Large Line-of-Sight Deformation

Synthetic Aperture Radar Interferometry (InSAR) provides one-dimensional measurements on ground displacement in the radar line-of-sight (LOS) direction. Multiple-Aperture Interferometry (MAI) technique has been successfully used to measure along-track ground displacement. However, the technique occasionally shows filtering boundary artifacts along the boundary of incoherent areas and a loss of MAI coherence in the presence of large and complex LOS deformation. In this study, we propose an efficient MAI processing method to mitigate them and improve computational efficiencies as well. We validated the performance of the proposed MAI method using ALOS PALSAR interferometric pair acquired from the ascending orbits on June 12, 2007 and August 2, 2009. The test pair includes large and complex LOS deformation signals accumulated from several dike intrusions and fissure eruptions. Through the proposed MAI processing method, we have generated the InSAR and MAI interferograms with the pixel spacing of about 45 and 40 m in ground range and azimuth directions, respectively. Close to surface rupture, we found that our proposed method improved the MAI coherence from 0.33 to 0.96 and reduced the filtering boundary artifacts from 0.068 to 0.040 rad. The results demonstrate the potential of the proposed method to measure along-track ground displacement in regions of decorrelation.