高速旋转弹丸进动周期提取

对高速旋转弹丸的雷达回波进行处理,可以提取弹丸的进动周期.进动是弹丸平动之外的微动,弹轴围绕质心速度方向旋转对雷达回波产生微多普勒频率调制.对进动引起的微多普勒建模分析表明,散射点的径向速度是质心径向速度与进动引起的微动速度之和.利用短时傅里叶变换计算含有微动信息的散射点径向速度,然后采用分段多项式拟合获取质心径向速度.散射点径向速度减去质心径向速度可以得到微动速度.对微动速度进行时域滑窗自相关处理,可以提取弹丸进动周期.仿真分析和对弹丸实际测量数据处理表明:该方法可以有效提取高速旋转弹丸的进动周期.

Precession period extraction of high-rate rotating projectile

Precession is conical motion that projectile axes rotate around the projectile velocity direction in flight. Precession is one of micro-motions in addition to the translation. Precession produces frequency modulation on the returned radar signal and induces additional Doppler shifts to the Doppler frequency shift caused by translation, called micro-Doppler effect. The mathematics of micro-Doppler signatures shows that the reflector radial velocity is the sum of the mass center radial velocity and the micro velocity. The reflector radial velocity contains the information about precession, which can be obtained by using the short time Fourier transform(STFT). The mass center radial velocity can be derived from polynomial expressions. The velocity subtracted from the reflector radial velocity gives the micro velocity.Time-domain and frequency-domain analyses were jointly adopted. The sliding window autocorrelation of the micro velocity was also used to measure precession period. Both computer simulation and the experimental results demonstrate the validity.