This paper reports the investigation on the micromotion characteristics of chaff dipoles and a chaff cloud. Micromotion models of chaff dipoles and steady-state chaff clouds are discussed. Fourier transform method and time-frequency method are used to study the micromotion features of chaff dipoles, in the energy domain and time-frequency domain, respectively. Based on the characteristic parameters in these two domains, the simulation results show that there are micro-Doppler frequency components in the echo signals from chaff dipoles, and these frequency components vary periodically. Then, the micro-Doppler frequencies of chaff cloud are obtained based on the method of multipoint synthesis. Finally, the experimental results of chaff dipoles dispersion verify the micromotion characteristics of chaff dipoles and chaff cloud obtained by using the empirical mode decomposition method and the short-time Fourier transform method.

本文报道了谷壳偶极子和谷壳云的微运动特征的研究。讨论了谷壳偶极子和稳态谷壳云的微运动模型。利用傅里叶变换法和时频法研究了谷壳偶极子在能量域和时频域的微运动特征。基于这两个域的特征参数，仿真结果表明，谷壳偶极子回波信号中存在微多普勒频率分量，并且这些频率分量周期性变化。然后，基于多点合成方法，获得了谷壳云的微多普勒频率。最后，