基于经验小波变换的目标加速度估计算法

加速度会使目标回波信号的频谱展宽甚至偏移,使传统脉冲雷达测速方法不能准确估计信号的多普勒频率.为了克服目标的加速度对脉冲雷达测速的影响,提出了一种基于经验小波变换(EWT)的径向加速度估计算法.对回波信号进行EWT变换和能量型频率主成分提取方法得到回波信号瞬时频率,并利用抗差最小二乘拟合得到相位高阶系数,进而估计目标径向加速度.利用估计的加速度对信号频谱进行补偿就能准确估计信号的多普勒频率.仿真表明EWT方法是一种高精度快速算法,且估计误差最接近待估参数的C-R下界.实测高速飞行器脉冲雷达I/Q数据验证表明,EWT算法估计的加速度精度优于0.4 m/s2.该算法可应用于脉冲雷达实时加速度估计.

Estimation of target's acceleration based on empirical wavelet transform

Target's accelerations lead to spectrum shift and broadening of target's echo signal, resulting in the inaccuracy estimation of target's Doppler frequency with traditional pulse radar velocity measurement method. To overcome the effect of acceleration on pulse radar velocity measurement, an empirical wavelet transform (EWT) based radial acceleration estimation method was proposed. The instantaneous frequency of the echo signal can be extracted through EWT and energy-oriented principal frequency components extraction method. The high order coefficients of the phase were obtained through robust least square fitting on the instantaneous frequency, which correspond to the radial velocity and radial acceleration respectively. After compensating the echo signal with estimated accelerations, the Doppler frequency of echo signal can be accurately estimated. Simulations show that the EWT method is a fast algorithm with high estimation accuracy, and the estimation error is close to Cramer-Rao lower bound. Applying EWT method on measured pulse radar data of high speed vehicle, the estimated acceleration error is smaller than 0.4 m/s². EWT method is applicable in real time pulse radar acceleration estimation.