Randomized stepped-frequency (RSF) radar, which transmits random-frequency pulses in a coherent processing interval (CPI), has an excellent electronic counter-countermeasures (ECCM) performance and the ability to synthesize wide-frequency band with a narrow bandwidth receiver. However, due to the use of different frequency pulses, RSF waveform is incompatible with the conventional moving-target-detection (MTD) technique, which makes clutter suppression a difficult problem for RSF radar and limits its application. In this article, the effect of clutter on the coherent processing for RSF radar is first analyzed. The result shows that coherent processing can improve the signal-to-clutter ratio on target Doppler channel by $N$ (number of pulses in one CPI) times, which suppresses weak clutter scatterers to a large extent whilst strong clutter scatterers would still be left influential. Focusing on dominant clutter scatterers, the adaptive range-Doppler clutter suppression algorithm, which is based on designing clutter suppression filters with two-dimensional property to obtain the clear high-range-resolution profile of moving target in clutter environment, is then proposed for RSF radar. The proposed algorithm, which takes into account clutter Doppler extension, can be used for RSF radar coherent processing in clutter environment.

中文翻译：

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随机步进频率雷达中的自适应杂波抑制

随机步进频率（RSF）雷达以相干处理间隔（CPI）发射随机频率脉冲，具有出色的电子对抗（ECCM）性能，并能够通过窄带宽接收器合成宽频带。但是，由于使用了不同的频率脉冲，RSF波形与常规的移动目标检测（MTD）技术不兼容，这使得杂波抑制成为RSF雷达的难题，并限制了其应用。在本文中，首先分析了杂波对RSF雷达相干处理的影响。结果表明，相干处理可以通过以下方法提高目标多普勒信道上的信杂比：$ N $（一个CPI中的脉冲数）倍，这在很大程度上抑制了弱杂波散射体，而强杂波散射体仍然具有影响力。针对主要的杂波散射体，提出了一种自适应距离多普勒杂波抑制算法，该算法基于二维特性的杂波抑制滤波器的设计，以获取清晰的杂波环境下运动目标的高分辨率分辨率轮廓图。雷达。该算法考虑了杂波多普勒扩展，可用于杂波环境下的RSF雷达相干处理。