Method to suppress moving targets in SAR images

In the high-resolution wide-swath (HRWS) SAR system, the moving targets are usually smeared and imaged at incorrect positions in the resulting SAR image by utilizing the traditional stationary scene imaging processing. Moreover, these defocused moving targets may cover the stationary scene. The number of spatial degrees of freedom required for suppressing moving targets by the traditional space-time adaptive processing framework is equal to the number of the moving targets in the SAR scene multiplied by the PRF undersampling number. This requirement is hard to meet in practice. In order to overcome the above problem, a new space-time adaptive processing framework based on azimuth Deramp processing is proposed in this paper. Firstly, the moving targets are coarsely focused in the space-time plane through the azimuth Deramp processing. In this case, only one spatial degree of freedom is needed for suppressing one moving target. If there are multiple targets, it can effectively reduce the required degrees of freedom by utilizing the dynamic steering vector concept. Last, simulation results are provided to show the validity of the proposed method.