Analysis of the Spatial-variation Features of Scintillation Phase Error in Spaceborne Synthetic Aperture Radar Images

The amplitude and phase scintillation effect imposed by ionospheric irregularities result in low frequency spaceborne synthetic aperture radar (SAR) azimuth-imaging defocus. Different from the motion phase error and tropospheric phase error, the scintillation phase error (SPE) shows spatial-variation features for distinct targets in scene. This paper constructs the ionospheric propagation geometry of spaceborne SAR for spatial distinct targets, and analyzes the spatial variation features of SPE along azimuth, range and anisotropic extending projection direction. The simulation results demonstrate that the SPE is overlapped along the azimuth direction and has similar characteristics along the anisotropic extending projection direction. Besides, the SPE changes slowly along the distance direction under isotropy, but has the characteristics of staggering under anisotropy. These features will be further applied in estimating and compensating SPE.