Integrating Agile Waveforms With DBF for HRWS SAR Imagery and Adaptive Jamming Suppression

Range ambiguity resolving and deceptive jamming suppression are both challenges for high-resolution wide-swath SAR imagery. With the accommodation of the digital beamforming (DBF) techniques, agile waveforms are of potential to tackle the ambiguity-resolving and antijamming tasks simultaneously. In this article, an algorithm blending agile waveforms and elevation DBF is proposed for wide-swath SAR imagery and adaptive jamming suppression. A shift-stepped Costas DFC (SSC-DFC) waveform is developed with optimal shifted orthogonality. Compared with the orthogonal waveform with smeared ambiguous energy, SSC-DFC can provide precise ambiguity energy position for the spatial filter construction. Meanwhile, cyclic shifts coherence of the agile waveforms minimizes the azimuth ambiguity residual after the Doppler filtering. A serial DBF is designed for adaptive false target extraction and jammer location estimation. The jammer direction notch is only added in the false target area while executing the wide image deblurring. The subregion DBF avoids the dark strip in the final wide-swath image effectively. Extensive simulation has been presented to verify the practicability of the proposed scheme.