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基于最大似然的单通道交叠激光微多普勒信号参数分离估计
引用本文:郭力仁,胡以华,王云鹏,徐世龙.基于最大似然的单通道交叠激光微多普勒信号参数分离估计[J].物理学报,2018,67(11):114202-114202.
作者姓名:郭力仁  胡以华  王云鹏  徐世龙
作者单位:1. 国防科技大学电子对抗学院, 脉冲功率激光技术国家重点实验室, 合肥 230037; 2. 国防科技大学电子对抗学院, 电子制约技术安徽省重点实验室, 合肥 230037
基金项目:国家自然科学基金(批准号:61271353)资助的课题.
摘    要:利用激光对目标微弱振动进行探测有利于获得明显的微多普勒效应,这为精确估计目标微动特征参数,实现对目标的分类和精细识别提供了可能.但对于多散射点或多目标激光探测,信号为单通道多分量微动混合的形式,而且补偿目标主体运动后,数值上相近的微动参数还会导致信号在时频域存在严重的交叠.为从这类混合信号中精确估计各分量的微动参数,本文提出了基于最大似然框架的参数分离估计方法.利用精细化扫描的奇异值比谱法从混合信号中获得目标微动频率,并得到各分量的幅值比信息.推导了微动参数最大似然估计的解析表达形式,根据激光微多普勒信号的特点从频谱能量分布的角度重新设计了似然函数,解决了传统似然函数在激光微动信号中出现的高度非线性问题,降低了初始化的要求,提高了抗噪性能,并采用马尔可夫-蒙特卡罗方法具体实现了参数的估计.在微动参数得到估计的基础上给出了信号的幅值和初相的估计方法.用本文方法对仿真和实验数据进行处理,得到了接近克拉美罗下界的估计结果,验证了方法的有效性.与传统非参数化估计方法的对比结果体现了所提方法对混合微动参数精确估计上的优势.

关 键 词:激光微多普勒  参数估计  最大似然估计  奇异值比谱
收稿时间:2017-12-12

Separate estimation of laser micro-Doppler parameters based on maximum likelihood schemes
Guo Li-Ren,Hu Yi-Hua,Wang Yun-Peng,Xu Shi-Long.Separate estimation of laser micro-Doppler parameters based on maximum likelihood schemes[J].Acta Physica Sinica,2018,67(11):114202-114202.
Authors:Guo Li-Ren  Hu Yi-Hua  Wang Yun-Peng  Xu Shi-Long
Affiliation:1. State Key Laboratory of Pulsed Power Laser Technology, College of Electronic Engineering, National University of Defense Technology, Hefei 230037, China; 2. Anhui Province Key Laboratory of Electronic Restriction Technology, College of Electronic Engineering, National University of Defense Technology, Hefei 230037, China
Abstract:Laser micro-Doppler (MD) effect is capable of obtaining obvious modulation in weak vibration detection. It helps to estimate target micro-motion parameters with high precision, which may extend the application field of MD to subtle identification and recognition. In laser detection, the multiple scattering points in the field of view will generate the single-channel multi-component (SCMC) signal. Moreover, the micro-Doppler features of each component will be overlapped in the time-frequency domain because of the similar micro-motion parameters. The overlapped SCMC signal makes the estimation of the MD parameters a very difficult problem, and there has been no good method so far. In this paper, a separate parameter estimator based on the maximum likelihood framework is proposed to deal with this underdetermined problem. First, the detailed period scanning method is presented to improve the estimation accuracy of micro-motion frequency from the singular value ratio (SVR) spectrum. Further, the amplitude ratio information of each component is extracted from the SVR spectrum. Then, the closed-form expressions of the maximum likelihood estimation (MLE) for the remaining micro-motion parameters are derived, where the mean likelihood estimation is used to approximate to the performance of MLE. The high nonlinearity and multi-peak distribution shape of the likelihood function (LF) in laser MD signal will lead to incorrect estimation result. To this end, a new LF based on the energy spectrum characteristics is designed. The new LF acts as a smoothing filter to the probability density function, through which the ideal PDF distribution form that has only one smooth peak is obtained. With this modification, the requirements for the initialization are reduced and the robustness in low SNR situation is increased. The Markov chain Monte Carlo sampling is employed to implement the MLE. The Gibbs method is chosen to solve the multi-dimensional parametric problems, and the detailed process is listed. In the end, the simulation results prove the feasibility and high efficiency of the proposed method. The accuracy of parameter estimation reaches the Cramer-Rao boundary. The inverse Radon transform is used as a comparison with the experiment, and the results show the precise estimation advantage of the presented method.
Keywords:index terms-laser micro-Doppler  parameter estimation  maximum likelihood estimation  singular value ratio spectrum
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