弹丸在膛内运动的回波信号瞬时频率估计方法研究

摘要

微波干涉仪可获取含内弹道运动信息的多普勒回波信号,为有效地估计回波信号的瞬时频率,利用短时傅里叶变换、Wigner-Ville变换、多项式调频小波变换(PCT)等方法对含有不同噪声的模拟弹丸回波信号和真实的弹丸回波信号进行分析和对比.研究结果表明:多项式调频小波构造匹配变换核的PCT方法时频聚集性最好,瞬时频率估计精度最高,并具有一定的抗干扰能力,说明PCT方法适合于弹丸在膛内运动回波信号的瞬时频率估计.%The microwave interferometer can obtain the Doppler echo signal containing interior ballistic motion information.In order to estimate the instantaneous frequency of echo signal effectively,a mathematical model of motion curve of projectile in bore is established based on polynomial fitting.The methods of short-time Fourier transform,Wigner-Ville distribution,polynomial chirplet transform (PCT)are used to analyze the simulation echo signals of projectiles with different noise and experimental echo signals of projectiles,respectively.The results show that the PCT method which uses transform kernel based on polynomial frequency modulated wavelet has the best time-frequency concentration and accuracy of instantaneous frequency estimation (IFE) and good anti-interference ability compared with the other methods.The research results show that the PCT method is suitable for IFE of projectile's signals.