Robust Sea Clutter Suppression Method for Multichannel Airborne Radar
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摘要: 在机载预警雷达对海洋背景运动目标的探测过程中,雷达平台的高速运动状态使得海杂波多普勒谱发生严重展宽现象,影响目标的检测性能。针对此问题,空-时自适应处理是一种有效的杂波抑制技术,该技术利用杂波的空-时2维耦合特性进行杂波抑制。但相对于陆地杂波而言,海杂波的内部复杂运动特性使得杂波空-时谱发生展宽现象,导致杂波多普勒频率与空间锥角不再保持一一对应关系,从而影响杂波抑制效果。针对海杂波的运动特性,该文提出一种稳健的基于子空间投影的杂波抑制处理算法,所提算法通过滤波凹口自适应展宽技术和先滑窗滤波后自适应处理技术来提高杂波抑制的稳健性。最后通过仿真的海杂波数据和实测海杂波数据验证了所提算法的有效性。Abstract: During the marine moving target detection for airborne early warning radar, the high-speed movement of the radar platform causes the serious broadening of the sea clutter Doppler spectrum, which affects the target detection performance. To solve this problem, a clutter suppression method called Space-Time Adaptive Processing (STAP) is effective, which exploits the space-time coupling characteristics of clutter. However, compared with the land clutter, the motion characteristics of sea clutter lead to the broadening of the clutter space-time spectrum, resulting in the clutter Doppler frequency and the spatial cone angle no longer maintaining a one-to-one correspondence; thus the clutter suppression performance significantly degrades. According to the motion characteristics of sea clutter, a robust subspace projection method is proposed in this paper. This method improves the robustness of clutter suppression by using the adaptive notch broadening technique and the filter then adapt technique. Finally, the effectiveness of this method is verified through the simulation results and the real-measured sea clutter data.
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表 1 系统仿真参数
参数 值 平台高度 4000 m 平台运动速度 100 m/s 雷达频率 9.6 GHz 信号带宽 30 MHz 采样频率 36 MHz 接收机噪声带宽 36 MHz 脉冲重复频率 3000 Hz 脉冲数 90 波束中心下视角 60° 波束中心方位角 90° 方位通道数 8 天线方位维长度 1.000 m 天线俯仰维长度 0.125 m 发射增益 42.1 dB 接收增益 42.1 dB 发射天线方位和距离向加权 –13 dB/–13 dB(等幅加权) 接收天线方位和距离向加权 –40 dB/–20 dB(切比雪夫加权) 系统噪声 2 dB 系统损耗 11 dB 表 2 实测数据系统参数
参数 值 平台高度 3100 m 平台运动速度 80 m/s 雷达频率 9.6 GHz 脉冲重复频率 4000 Hz -
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