一种基于改进压缩感知的低信噪比ISAR高分辨成像方法

针对低信噪比下基于压缩感知(CS)的ISAR成像方法性能下降甚至失效的问题,该文提出了一种改进CS的成像方法,即用能量门限分离含目标的距离单元和噪声单元,同时在方位向上用相干投影来提高观测数据的信噪比,利用迭代加权的1-范数优化以增强真实散射点能量并且压制噪声. 改进CS算法适用于强噪声的环境下的ISAR成像,并可利用很少脉冲数获得高分辨的目标像.实测数据处理验证了该方法可以有效克服强噪声与杂波.同时,仅用16个回波脉冲就可得到高分辨ISAR图像,验证了该方法在非常有限脉冲条件下的稳健性.

A New Method of High Resolution ISAR Imaging under Low SNR Based on Improved Compressive Sensing

In consideration of the the issue of the weakness performance of Compressive Sensing (CS) ISAR imaging under low SNR condition, an improved CS method is proposed in this paper. Energy based threshold is proposed to identify range cells containing only noise, a coherent projection in cross-range to improve the SNR of measurements then a iterative re-weighting norm optimization is applied to enhance the signal recovery while reject noise. Moreover, an advantage of this robustness is the ability to produce a high quality image and is suitable for ISAR imaging by using very limited echoes under strong noise and clutter. Experimental result of real data processing verifies the proposed method’s capability of depressing noise or clutter and extracting strong scatterers to construct high resolution image. In the experiment, high quality image can be generated by using only 16 pulses and its robustness is confirmed too.