基于激光动态散斑的时频信号,建立了一套适用于角反射器阵列的微动参数反演算法。首先利用物理光学方法推导了角反射器及角反射器阵列激光散斑的实时强度公式,然后基于短时傅里叶变换研究了散斑功率谱形成机制及其数字特征,最后提出了频谱相关法及时频-相幅变换算法,并采用该方法提取了动态散斑时频谱线周期及振幅分布,反演了三种典型运动状态下目标的自旋周期及旋转轴指向。结果表明:基于几个周期的散斑强度序列,所提反演算法可以得到高精度的旋转周期及视线角,但对旋转轴方位角的反演精度相对较差,需要更多的观测数据才能得到满意的结果。

In this paper, a set of inversion algorithms for the micro-motion parameters in a retroreflector array was established based on the time-frequency signals of laser dynamic speckles. Firstly, the real-time intensitys formula of laser speckle from a retroreflector and a retroreflector array were derived by a physical optics method. Then, based on the short-time Fourier transform, the formation mechanism and digital characteristics of the speckle power spectrum were studied. Finally, the spectral correlation method and time-frequency to phase-amplitude transform algorithm were proposed, and the algorithm was used to extract the period and amplitude distribution of the time-frequency spectral lines of dynamic speckles. Besides, we made an inversion on the spin period and the direction of the rotation axis of a target in three typical motion states. The results show that the proposed inversion algorithm can obtain the rotation period and line-of-sight angle with high accuracy through speckle intensity signals in a few periods, but the inversion accuracy for the azimuth angle of the rotation axis is relatively poor. It follows that more observation data are required for satisfactory results.