Research on Anti-Deception Forwarding Interference of Squint Azimuth Multichannel SAR.

The demand for high-resolution and wide-swath (HRWS) for squint azimuth multi-channel SAR (MSAR) platform is increasingly urgently. However, the existence of interference will seriously contaminate the squint MSAR imagery, especially the deceptive forwarding interference (DFI) produced by the digital radio frequency memory (DRFM) technology makes the SAR imagery confusing. For this point, the research on anti-DFI of squint MSAR is discussed in detail in this paper. The presence of the Doppler ambiguity of the signal increases the complexity and difficulty of the DFI suppression. To solve this problem, the difference in the space-time spectrum between the valid signal and the DFI is first analyzed, and the steering vectors of each component in the echo are mined as prior information. Based on the prior information, a two-step processing is performed: the first step is to suppress the main-lobe DFI by using subspace projection; and the second step is to suppress side-lobe DFI and complete signal spectrum reconstruction with the multiple Doppler direction linearly-constrained minimum variance (MDD-LCMV) beamformer. Finally, the two experiment results show that the excellent performance of the proposed method in squint MSAR for suppressing DFI.