进动圆锥弹头双基地微多普勒特性分析

Bistatic Micro-Doppler Feature of the Precessing Cone-shaped Warhead

微动特征是弹道中段目标雷达识别的有效特征之一。该文首先利用由几何绕射理论推导的圆锥弹头散射中心模型确定了3个散射中心分别是锥顶及双基地角平分线在锥底平面上的投影与底面边缘的2个交点;然后建立了进动圆锥弹头双基地微多普勒模型,经化简可知双基地微多普勒模型与双基地角平分线上单基地雷达微多普勒模型相似,且双基地微多普勒幅值为单基地微多普勒幅值的半双基地角的余弦倍,这与单双站散射等效定理吻合;再通过分析3个散射中心的微多普勒模型得出了可用于进动和结构参数估计的3种相关性;最后利用电磁计算软件FEKO计算了圆锥弹头模型的双基地雷达截面积(RCS),通过对RCS序列的时频分析,验证了该文理论分析的正确性。

Micro-motion feature is one of the effective features used for radar target recognition in the middle section of the ballistic curve.Using the scattering centers of the cone-shaped warhead analyzed by the Geometrical Theory of Diffraction（GTD）,it is concluded that the cone-shaped warhead has three scattering centers,one is at the conical point,and the other two are the points where the projection of the bistatic bisector on the conical bottom intersects the edge of the conical bottom,firstly.Then the micro-Doppler（m-D） models of the scattering center at the conical point and two slip-type scattering centers on the edge are derived.They are similar with the monostatic m-D models of the scattering centers when the radar locates on the bistatic bisector,and the amplitude ratio of the m-D in the bistatic radar and monostatic radar is the cosine of the half of the bistatic angle.It coincides with the monostatic-bistatic equivalence theorem.Three correlations of the m-D of the three scattering centers are founded by analyzing their m-D expressions.Finally,the bistatic Radar Cross Section（RCS） of the cone-shaped warhead model are calculated by using FEKO.The theoretic analysis of the m-D expressions is verified from the time-frequency analysis on the bistatic scattering coefficients.