Ambiguities Suppression for Azimuth Multichannel SAR Based on ${L_{2,q}}$ Regularization With Application to Gaofen-3 Ultra-Fine Stripmap Mode

The azimuth multichannel synthetic aperture radar (SAR) technology is capable of overcoming the minimum antenna area constraint and achieving high-resolution wideswath (HRWS) imaging. Generally speaking, pulse repetition frequency (PRF) spaceborne SAR systems should satisfy azimuthal uniform sampling condition, but it sometimes impossible due to limitation system timing conditions, which often referred as “coverage diagram.” For Gaofen-3 system, PRF each channel at some beam positions slightly less than that in dual-channel mode, leading nonuniform undersampling, hence, resulting ambiguities recovered images. Although ambiguous energy images not high general, still noticeable amid surrounding weak clutters strong targets. In this article, a novel imaging method for undersampling based on L 2,q regularization (0 <; q ≤ 1) proposed. By analyzing reasons model established with emphasizing difference from conventional single-channel SAR. Then, we combine data processing operators group sparsity property construct method. modeled by 2, q-norm, problem can be solved via sparse thresholding function. It shown proposed efficiently suppress caused undersampling. Simulations real experiments are exploited verify effectiveness