Generalized BP-InSAR Processing With High-Squint Geometry

Most of the interferometric synthetic aperture radars (InSARs) operate in zero-squint or low-squint geometry. A spatial phase ramp in focused squint SAR images leads to a higher demand for coregistration, which limits the application of InSAR. This letter investigates InSAR processing with a high squint angle. The spatial phase ramp is here directly used for the construction of the digital elevation model (DEM). The method based on back projection algorithm (BPA) is analyzed first. Then the form of the interferometric phase for BPA is derived with the existence of squint, proved to share the same form as conventional InSARs. The restriction that relates to coherence is also discussed. A processing flow without coregistration is finally presented. Simulated two-channel SAR data validates the proposed method.