Beamforming is an effective way of resolving target direction and anti-jamming in short wave (SW) radar systems. In conventional beamforming (CBF) at a certain frequency, to get high resolution, the array aperture should be increased, and this is often not allowed in practical applications. A new narrow beam forming (NBF) method for beam sharpening based on the generalised oblique projection (GOP) filter with a flexible parameter is proposed. This method uses a GOP filter bank to form deep nulls in the undesired azimuth range on the pattern and utilises the logic product process to synthesise the GOP filters’ outputs and thus obtains a narrow beam. Compared to traditional beamforming methods, the result of NBF has the characteristics of narrower beam width and bigger side lobe suppression ratio (SLSR). Especially, a narrower beam can be obtained in the case of a small array aperture, which is valuable for practical applications. Experimental results of the range-Doppler spectrum of short wave radar show that this narrow beam forming method can achieve super resolution of targets within a wide beam and greatly suppress clutter. Therefore, NBF can improve the azimuth resolution and achieve interference suppression in a conventional beam.

中文翻译：

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基于灵活参数广义斜投影算子的短波雷达波束锐化方法

波束形成是短波（SW）雷达系统中解析目标方向和抗干扰的有效方法。在传统的波束形成（CBF）中，在一定频率下，为了获得高分辨率，需要增加阵列孔径，而这在实际应用中往往是不允许的。提出了一种基于具有灵活参数的广义倾斜投影（GOP）滤波器的新型窄波束形成（NBF）波束锐化方法。该方法使用GOP滤波器组在图案上不需要的方位角范围内形成深零点，并利用逻辑乘积过程来合成GOP滤波器的输出，从而获得窄波束。与传统的波束形成方法相比，NBF的结果具有波束宽度更窄、旁瓣抑制比（SLSR）更大的特点。特别是在阵列孔径较小的情况下可以获得较窄的光束，这对于实际应用具有重要价值。短波雷达距离-多普勒频谱实验结果表明，这种窄波束形成方法可以实现宽波束内目标的超分辨，并极大地抑制杂波。因此，NBF可以提高方位角分辨率并实现对常规波束的干扰抑制。