基于雷达极化理论的弹丸飞行姿态电磁散射特征

针对用线极化天线测速雷达测量弹丸飞行姿态问题,利用电磁理论推导并分析了底部刻槽弹丸的姿态特征参数。首先由雷达电轴与刻槽弹丸对称轴之间的关系,建立弹体散射矩阵,得到散射场的粗略表示,说明刻槽测量姿态的原理;其次,利用理想导体上无限长窄槽的表面等效磁流的近似表达式,详细推导了凹槽散射的远场表达式;再次,比较了刻槽后平行极化与垂直极化的远区散射场,用解析法和数值法仿真了不同飞行姿态下刻槽对弹丸散射回波的调制作用并与实测数据进行了比较,数值仿真了姿态特征参数的单调性;最后,对姿态特征参数的增强方法进行了简要的讨论和展望。仿真结果表明,在一定章动角范围内,该姿态特征参数能够表征弹丸的飞行姿态,具有相对稳健性和单调性。

Electromagnetic Scattering Signature on Attitude of Flying Projectiles Based on Polarization Theory

In regard to acquire the attitude of flying projectiles using velocity measurement radar with linear polarization antenna, a characteristic parameter was deduced and analyzed based on polarization theory by slotting at the bottom. First, according to the relation between electronic axis of radar and the axis of projectile, the scatter matrix that could express the field coarsely was deduced. Second, using the approximated expression of equivalent surface magnetic current of infinite long narrow slot on the perfect conductor, an analytic solution of finite long groove was achieved. Third, the far zone scatter fields of HH and VV polarization were compared. The amplitude modulation under different flying attitude was simulated by analytic and numerical method respectively. The monotonous characteristic was also simulated. At last, the methods to enhance the attitude signature were discussed. Through compared with simulation results and measurement data, it can conclude that the parameter can display the attitude of flying projectiles. The signature is steady and monotonous.