Multiple Aperture InSAR (MAI) Processor: ALOS, Envisat and ERS implementation; Potential Implications for InSAR Time Series

MAI is an interferometric technique for extraction of along-track displacements from InSAR measurements. MAI results are less susceptible to different error sources compared to InSAR or pixel-offsets. Its implementation requires 'deskewing' the SAR images (SLC's), but deskewing is not available in widely used academic InSAR processors. (By 'deskew' we refer to the process of referencing the SAR signal to zero-Doppler). We implemented a deskew capability to ROI_PAC's SAR processor, and used the new feature to build a ROI_PAC-based MAI processor. We present here the MAI processing steps, and demonstrate the new processor with ALOS, ERS and Enivsat data. We discuss precision and coherence using MAI pairs with zero expected along-track deformation for each satellite's data. Some InSAR time-series applications require deskewed SLC's for optimal performance. The deskewed SLC's are referenced to the point of closest approach (perpendicular to the orbit), and the images have the same pixel shapes regardless of Doppler centroid used for processing. In addition to the MAI processor, we integrated the new deskew feature into the ROI_PAC InSAR processor.