基于半波相消的旋转叶片微动回波时频分析

Time-frequency Analysis of Rotating Blades Micro-motion Echo Based on Half-wave Cancellation

在雷达探测场景中常见旋转引起的微多普勒效应,产生的微动特征与目标的几何和运动参数相关。文中从微动回波的线积分模型出发,基于半波相消的角度对旋转叶片微动回波时频特征形成机理进行了全面分析。首先在远场条件下,基于半波相消分析了旋转微动瞬时频率的形成机理,解释了其旋转微动时频特征的双端效应。进一步地,将半波相消分析扩展至近场条件,解释了近场条件下时频图双端区和镜面散射区凸显的效应。对于远场和近场条件,该文均给出了时频结果的定量解析计算方法。从图像形状和能量变化的角度对近、远场的时频特征进行分析,讨论了不同条件和参数对时频特征形状和细节的影响,基于半波相消分析将近场和远场分析统一起来,同时将线积分模型和局部散射模型联系起来。仿真实验验证了所提分析方法的正确性。

The rotation-induced micro-Doppler effect is common in radar detection scenarios,and the resulting micro-motion features are related to the geometric and kinematic parameters of the target.This paper comprehensively analyzes the formation mechanism of rotating blades micro-motion echo time-frequency features based on half-wave cancellation from the line integral model of micro-motion echo.Firstly,the formation mechanism of the instantaneous frequency of rotating micro-motion is analyzed under the far-field condition based on half-wave cancellation,which explains the double-end effect of the time-frequency characteristics of rotating micro-motion.Further,the half-wave cancellation analysis is extended to the near-field condition,and the effect of the double-ended region and the specular scattering region of the time-frequency diagram accentuated under near-field conditions is explained.Moreover,for both far-field and near-field conditions,this paper gives a quantitative analytical calculation method for the time-frequency results.This paper analyzes the time-frequency features of near-field and far-field from the perspectives of image shape and energy change,discusses the effects of different conditions and parameters on the shape and details of the time-frequency features,and unifies the near-field and far-field analyses based on the half-wave cancellation analysis,meanwhile,the line integral model and the local scattering model are linked.The simulation experiments verify the correctness of the proposed analytical methods.