复杂极端天气预报中雷达基数据不均匀杂波感知系统设计

Design of radar based data non-uniform clutter perception system for complex extreme weather forecasting

摘要:

在C/S波段相控阵天气雷达于复杂强水汽梯度环境下执行扫描时,易因非线性相控阵波束赋形畸变而产生杂波峰值。若此时采用固定频率的宽脉冲信号进行探测,并对接收到的包含均匀/非均匀杂波的原始回波进行直接采样与量化,则系统将难以准确修正多普勒频率估计值,导致杂波能量在空间域分布宽散、聚焦性差,最终表现为目标反射杂波与背景反射杂波无法有效区分,且与真实杂波分布之间存在显著空间偏差。为此,设计复杂极端天气预报中雷达基数据不均匀杂波感知系统。系统硬件采用TRM-220C相控阵天线与RMA-100S抛物面天线异构融合架构,结合TISN65LVDS95+BCM54680多协议接口芯片、P500双模授时模块以及STM32H743ZI高保真控制器,实现杂波特征的高保真捕获与时序协同。软件部分提出联合脉冲压缩与动态衰减补偿的核心处理算法。利用TRM-220C相控阵天线硬件系统获取回波,结合全局同步时序对信号进行距离-多普勒二维离散化表征。采用线性调频信号发射策略,经匹配滤波脉冲压缩处理,实现雷达原始数据中非均匀杂波信号的离散化表达。通过置信度修正、加权相位补偿与协方差矩阵迭代重构,动态校正因目标干扰和环境时变导致的谱估计偏差,实现对不均匀杂波多维度精准感知。降雪与强对流场景下的实验结果表明,该方法感知的杂波能量集中在空间频率[?0.1,0.1]、多普勒频率[?0.4,0.4]区间,空间聚焦范围收窄,聚焦性强,能够区分目标反射杂波与背景反射杂波,且与真实杂波分布偏差仅为10m,从而验证了所提方法在杂波聚焦性与区域区分能力上的优势。

Abstract:

When the C/S band phased array weather radar performs scanning in a complex and strong water vapor gradient environment, it is prone to generating clutter peaks due to the beamforming distortion of the nonlinear phased array. If a wide-pulse signal of a fixed frequency is used for detection at this time, and the original echoes containing uniform/non-uniform noise are directly sampled and quantized, the system will find it difficult to accurately correct the Doppler frequency estimate, resulting in a wide and scattered distribution of noise energy in the spatial domain and poor focusing. Ultimately, it is manifested as the inability to effectively distinguish the target reflection noise from the background reflection noise. And there is a significant spatial deviation from the actual clutter distribution. For this purpose, a radar base data non-uniform clutter perception system is designed for complex extreme weather forecasting. The system hardware adopts a heterogeneous fusion architecture of TRM-220C phased array antenna and RMA-100S parabolic antenna, combined with TISN65LVDS95+BCM54680 multi-protocol interface chip, P500 dual-mode timing module and STM32H743ZI high-fidelity controller, to achieve high-fidelity capture and timing coordination of clutter characteristics. The software part proposes a core processing algorithm that combines pulse compression and dynamic attenuation compensation. The echo is obtained by using the TRM-220C phased array antenna hardware system, and the signal is characterized by distance-Doppler two-dimensional discretization in combination with the global synchronous timing sequence. By adopting a linear frequency modulation signal transmission strategy and undergoing matched filtering and pulse compression processing, the discretization expression of non-uniform clutter signals in the original radar data is achieved. Through confidence correction, weighted phase compensation and iterative reconstruction of the covariance matrix, the spectral estimation deviation caused by target interference and environmental time-varying is dynamically corrected to achieve multi-dimensional precise perception of non-uniform clutter. The experimental results in the scenarios of snowfall and strong convection show that the clutter energy perceived by this method is concentrated in the intervals of spatial frequency [-0.1,0.1] and Doppler frequency [-0.4,0.4]. The spatial focusing range is narrowed, the focusing ability is strong, it can distinguish the target reflected clutter from the background reflected clutter, and the deviation from the real clutter distribution is only 10m. This verified the advantages of the proposed method in terms of clutter focusing and regional discrimination ability.