基于杂波对消-自聚焦的多通道SAR-GMTI

对超高频(UHF)波段多通道合成孔径雷达(SAR)动目标检测技术进行研究,解决了长相干积累时间导致动目标在方位向散焦严重的问题。采用分块自聚焦技术对多通道SAR地面移动目标指示(GMTI)系统自适应杂波抑制后的SAR图像进行处理,改善杂波抑制后的SAR图像中动目标的聚焦情况,增强动目标与周围剩余杂波的对比度,进而提高恒虚警率(CFAR)检测的性能。与传统杂波抑制后直接进行CFAR检测方法相比较,该方法降低了检测虚警概率。实测数据处理结果显示动目标的信杂比明显提高,动目标方位向聚焦成功,证明了该方法的有效性。

Multichannel SAR-GMTI based on clutter cancellation and autofocus

The signal process technique of ultra-high frequency (UHF) band multichannel synthetic aperture radar (SAR) moving target detection is studied. The problem of moving target blurring caused by long coherence time in azimuth is solved. The sub-block image autofocus technique is proposed to process the clutter suppressed image of the multichannel SAR ground moving target indication (GMTI) system. The depth of the moving target focusing is increased after autofocus. The contrast between the moving target and the surrounding clutter is increased. The detecting performance of the constant false alarm ratio (CFAR) detector is improved. Compared with traditional method which is implemented by directly using CFAR detector after the clutter suppression, the detecting false alarm probability of the proposed method is lower. Processing results of the real collection data show that the signal to clutter ratio of the moving target increases significantly. Moving targets are well focused in azimuth after the processing of autofocus. The effectiveness and feasibility of the method are demonstrated by the processing results of the real collection data.