Detection, Parameters Estimation and Imaging of Moving Targets based on Extended Post-Doppler STAP in Multi-channel WasSAR-GMTI

As a new observation mode, wide-angle staring synthetic aperture radar ground moving target indication (WasSAR-GMTI) which can observe the fixed area for a long time and achieve moving target tracking has attracted a lot of interest. However, with increasingly complex flight trajectories and application scenarios, the performance of traditional method tends to degrade. In this paper, a novel approach based on post-Doppler space-time adaptive processing (PD-STAP) and imaging method is proposed. Firstly, selecting and extending training data from repeat-pass data can obtain accuracy estimated clutter covariance matrix (CCM). Moreover, the relationship between extended quantity of training data and clutter suppression performance is further analyzed in this paper. And then, the joint-pixel PD-STAP (JP PD-STAP) which utilizing auxiliary units under test cell along range direction is performed to overcome the effect of residual range curvature after keystone transform (KT). Finally, after clutter suppression, the parameters and imaging method based on WasSAR system is proposed. The multidimensional parameter is simplified as 1-D line search problem which has high efficiency. Considering the curvilinear trajectory, the Back-Projection (BP) is adopted to processed. Inserting parameters into BP can be seen as coarse motion compensation (MOCO), the further spectrum compression (SC) method and phase gradient autofocus (PGA) is performed to obtain refocus and relocate imaging of moving target. The real-measured WasSAR data processing results demonstrated the effectiveness and practicability of the proposed algorithm.