融合SMI和BSS的天气雷达CINRAD接收机旁瓣干扰抑制系统设计

Design of Side lobe Interference Suppression System for CINRAD Receiver of Weather Radar Integrating SMI and BSS

摘要:

在天气雷达CINRAD复杂电磁环境中,其接收机动态范围受限,当近程存在强杂波时,因幅度超出线性处理范围引发限幅效应,此效应破坏信号完整性,致使后续自适应旁瓣相消等抗干扰算法性能劣化,难以有效抑制旁瓣干扰,导致气象探测精度下降。为提高该雷达在旁瓣干扰下的抑制能力,设计了一种融合采样矩阵求逆(SMI)与盲源分离(BSS)的接收机干扰抑制系统。该系统采用能量削减与信号分离两级架构,实现从物理层到信号层的全方位干扰抑制。采用BSS技术盲源分离目标信号与干扰信号,有效剥离限幅效应引入的非线性干扰成分,提升旁瓣干扰抑制深度与鲁棒性,并采用滑动窗平均方法动态更新并平滑干扰协方差矩阵的估计求逆计算自适应权重,在干扰方向形成精准零陷,实现对旁瓣干扰能量的定向、量化衰减,同时保全目标信号能量。面向真实场景的系统验证结果表明,该系统能够使X2实部波形振幅抑制为0,将4-10μs时间段的X3实部波形振幅精准控制在[-0.1,0.1]范围内。而且,残留伪回波信号强度集中在15Hz–25Hz低能段,显著降低了对有效信号的掩蔽效应,提升了雷达在复杂电磁环境中的干扰抑制性能。

Abstract:

In the complex electromagnetic environment of the weather radar CINRAD, the dynamic range of its receiver is limited. When there is strong clutter in the short range, the amplitude is beyond the linear processing range, resulting in the limiting effect, which destroys the signal integrity, resulting in the performance degradation of the subsequent anti-jamming algorithms such as adaptive sidelobe cancellation, which is difficult to effectively suppress the sidelobe interference, resulting in the decline of meteorological detection accuracy. In order to improve the suppression ability of the radar under side lobe jamming, a receiver jamming suppression system combining sampling matrix inversion and blind source separation is designed. The system adopts a two-level architecture of energy reduction and signal separation to achieve omni-directional interference suppression from the physical layer to the signal layer. BSS technology is used to blind source separate the target signal and interference signal, effectively peel off the nonlinear interference components introduced by the limiting effect, improve the depth and robustness of sidelobe interference suppression, and the sliding window average method is used to dynamically update and smooth the estimation and inversion of the interference covariance matrix to calculate the adaptive weight, so as to form a precise null in the interference direction, realize the directional and quantitative attenuation of the sidelobe interference energy, and preserve the target signal energy. The system validation results for real-world scenarios show that the system can suppress the amplitude of the X2 real part waveform to 0 and accurately control the amplitude of the X3 real part waveform in the 4-10 μ s time period within the range of [-0.1, 0.1]. Moreover, the residual pseudo echo signal strength is concentrated in the low energy range of 15Hz-25Hz, significantly reducing the masking effect on the effective signal and improving the interference suppression performance of the radar in complex electromagnetic environments.