Target masking due to high sidelobes in the range-Doppler domain is a common problem in radar signal processing. Masking occurs when there is large variation in targets’ signal-to-noise-ratio levels, caused by differences in either range or radar cross section. In this letter, we consider the design of a waveform to reduce the masking of far range targets caused by near range targets. Our method is based on a time-frequency concatenation of a Costas sequence with shifted parts of itself. It allows the user to design a low sidelobe region in the range-Doppler domain. Moreover, it approximately preserves the desirable uniform sidelobe level and thumbtack behavior of the Costas ambiguity function. We demonstrate a 20 dB sidelobe level reduction within the desired region compared to a normal Costas code with the same bandwidth and pulse length.

中文翻译：

---

用于局部距离多普勒旁瓣电平降低的基于Costas的波形

在雷达信号处理中，由于距离多普勒域中的高旁瓣导致的目标掩蔽是一个普遍的问题。当目标的信噪比水平因范围或雷达横截面的差异而有很大变化时，就会发生掩蔽。在这封信中，我们考虑了减少近距离目标引起的远距离目标掩盖的波形设计。我们的方法是基于带有偏移部分的Costas序列的时频串联。它允许用户在范围多普勒域中设计一个低旁瓣区域。此外，它大致保留了Costas模糊度函数所需的均匀旁瓣电平和图钉行为。与具有相同带宽和脉冲长度的普通Costas码相比，我们证明了所需区域内的旁瓣电平降低了20 dB。