A Fast False Large-Scene Images Generation Method Against SAR Based on Two-Dimensional CZT and Multitransmitter Cooperation

In this article, a fast method for generating false large scenes against synthetic aperture radar based on the cooperative multitransmitter is proposed. First, we give an improved range frequency-shifting modulation (IRFSM) method utilizing the template chirp-Z transform (CZT) in range, which can help the transmitter accomplish the jamming modulation quickly. Then, with the derivation of formulas in the azimuthal Doppler domain, an azimuthal convolution and IRFSM jamming (ACIRFSMJ) method built on the two-dimensional CZT of the template is proposed. This ACIRFSMJ method can decouple the azimuthal and range directions to reduce the difficulties in the false large-scene signal generation process. The IRFSM ensures that the transmitter can quickly modulate the intercepted signal, while the azimuthal convolution modulation expands the coverage width of the false scene generated by a single transmitter in azimuth and avoids the distortion caused by ghosting and high sidelobes. However, when only using a single transmitter to generate false scenes, the azimuthal coverage width is still limited, and the jamming signal of most false scattering points is incomplete. Therefore, this article further proposes using multiple transmitters distributed along the azimuthal direction to address the shortcomings of a single transmitter. Theoretical analysis and experimental simulations verify the effectiveness of the proposed method.