Space-time Two-dimensional Clutter Suppression Method Based on Subarray Beam Pattern Design
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摘要: 机载雷达接收端采用子阵处理时面临栅瓣杂波导致的复杂空时耦合分布,使主瓣波束方向存在多个由栅瓣杂波导致的检测性能凹口,目标检测性能恶化严重。针对此问题,该文首先分析了子阵处理中栅瓣杂波空时谱分布特性,并在此基础上提出了基于接收子阵波束设计的空时二维杂波抑制方法。该方法采用重叠子阵构型方案,通过子阵方向图设计形成在子阵间栅瓣区域处的宽凹口,实现对子阵间栅瓣区域杂波的预滤波。进一步构建子阵级空时处理器,由于栅瓣杂波已经在子阵内完成预滤波,避免了栅瓣杂波在空时二维平面上的耦合扩散,从而提高了杂波抑制和动目标检测性能。仿真结果表明,所提方法显著改善了栅瓣杂波区的输出信杂噪比损失性能。Abstract: Airborne radar receivers that utilize subarray processing face challenges owing to the complex space-time coupling distribution caused by grating-lobe clutter. This results in multiple performance notches in the main beam, which severely affects target detection performance. To address this issue, we analyze the characteristics of grating-lobe clutter distribution in subarray processing and propose an approach for space-time clutter suppression based on the design of a receiving subarray beam pattern. Our approach leverages an overlapping subarray scheme to form wide nulls in the regions between subarrays where grating-lobe clutter is prevalent through beam pattern design. This design facilitates grating-lobe clutter pre-filtering between subarrays. Furthermore, we develop a subarray-level space-time processor that avoids the grating-lobe clutter coupling diffusion in the space-time two-dimensional plane by performing clutter pre-filtering within each subarray. This strategy enhances clutter suppression and moving-target-detection capabilities. Simulation results verify that the proposed method can remarkably improve the output signal to clutter plus noise ratio loss performance in grating-lobe clutter regions.
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表 1 雷达系统仿真参数
Table 1. Simulation parameters of radar system
参数 数值 参数 数值 阵元总数 52 子阵数 10 子阵内阵元数 16 重叠阵元数 12 脉冲数 16 工作载频 1.2 GHz 波长 0.25 m 脉冲重频 2 kHz 信号带宽 5 MHz 平台高度 10 km 平台速度 125 m/s 目标方位角 82.79° 目标俯仰角 4.99° 目标斜距 115 km 空间频率展宽 0.1 多普勒滤波器带宽 0.06 幅度误差 0.03 相位误差 3° 信噪比 –5 dB 杂噪比 50 dB -
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