Improved synthetic aperture radar micro-Doppler jamming method based on phase-switched screen

摘要

Target micro-motions such as rotation and vibration introduce phase modulation, termed as micro-Doppler (m-D) effect, onto synthetic aperture radar (SAR) signals. This causes ghost targets in the reconstructed SAR images. Inspired by this unique characteristic, a passive-jamming method based on m-D was developed for SAR. The m-D jamming method utilised a rotating reflector to intentionally generate ghost targets as jamming strips on the SAR image so as to protect certain areas. The m-D jamming method based on a single rotating reflector can only generate a long jamming strip along the azimuth direction but located in a finite number of range cells, which restricts the region of protected scene. In this study, an improved m-D jamming method based on phase-switched screen (PSS) is proposed, which combines the advantage induced by the PSS modulation and the usefulness of the m-D jamming. By controlling the modulating frequency and waveform of the PSS, the jamming strip is enlarged along the range direction. Theoretical analyses and simulation results verify the validity of the proposed method.