Impacts of time-variance background ionosphere on L-band geosynchronous SAR imaging

Due to the long integration time of Geosynchronous Synthetic Aperture Radar (GEO SAR), the variance of ionosphere within integration time cannot be ignored, thus it is necessary to take the effects of ionosphere variance into consideration. In this paper, a model is applied to describe the total electron content (TEC) variance within integration time. Then, the effect of phase error introduced by time-variance ionopshere on GEO SAR imaging is analyzed based on this model. After that, the mathematics expression of GEO SAR image displacement and image defocus is obtained, the corresponding influence is simulated. Finally, the conclusion is drawn.