An Effective Minimum Entropy Deconvolution and Zero-Phase Filter Algorithm for Blanket Jamming Suppression on Carrier-Free Ultra-Wideband SAR

Synthetic aperture radar (SAR) is a high-resolution microwave imaging radar. Compared to conventional SARs, the ultra-wideband (UWB) SAR exhibits a larger bandwidth and offers enhanced range resolution and image acquisition capabilities. However, the performance of UWB SARs can be compromised in electromagnetic interference environments, which leads to the production of inaccurate images. In this article, to address the blanket interference problem of UWB radar, we first establish the echo model of SAR under interference, then realize the detection and extraction of radar echo signal by the feature extraction method of minimum entropy deconvolution (MED), and recover the phase delay of the signal by filtering the noise with zero-phase filter. Finally, the time-domain inverse projection algorithm is used to image the distance target with high resolution and obtain the SAR image after suppressing the interference. The effectiveness of the proposed algorithm is demonstrated by simulated and measured data, and the performance evaluation criteria, such as root-mean-square error (RMSE), are used. When the SNR is lower than -30 dB, the RMSE between the original signal and the reconstructed signal of the experimental target can still be maintained at about 0.15.