空间锥体目标微多普勒提取与参数估计

发布时间：2018-08-28 08:42

【摘要】：微动是指目标或目标构件除质心平动以外的振动、转动和加速运动等微小运动,微动会对雷达回波产生多普勒调制效果,这种调制效果被称为微多普勒调制。而微多普勒特征能够反映目标的电磁散射特性、几何结构和运动特性,近几年来已经成为弹道导弹类目标分类识别的重要特征。本文主要研究了空间光滑锥体目标的微多普勒提取以及参数估计问题,从微动对回波的微多普勒调制、回波的微多普勒提取和进动目标的运动及结构参数估计三个方面展开并进行相关研究。论文的主要内容可以概括为如下三点:1、分析了光滑锥体目标的散射特性以及遮挡效应,建立了光滑锥体目标的等效散射点模型。以发射线性调频(LFM)信号为例,分析了进动和章动两种微动形式对目标雷达回波的多普勒调制作用,详细推导了其瞬时微多普勒频率的数学形式。最后通过仿真实验验证了理论分析的正确性。2、针对表面光滑的空间锥体目标,提出了一种线性调频信号参数估计结合随机抽样一致性(RANSAC)算法的微多普勒频率提取方法。该方法不直接对微动特性预先建模,而将回波分段后的信号近似为若干散射点对应的线性调频信号分量的叠加,通过估计出各个线性调频信号的调频率以及初始频率,然后利用随机抽样一致性进行模型拟合获得不同散射点的微多普勒频率曲线。通过仿真实验验证了此算法的有效性和稳健性。3、对于空间进动锥体目标的参数估计问题,介绍了一种估计目标进动参数和结构参数的方法。分析了不同雷达视线角下锥顶与锥底散射点瞬时微多普勒频率的变化关系,依据这种变化关系通过解方程的方法估计雷达视线角,然后估计目标的运动参数和结构参数,实现了目标高度、底面圆半径、旋转中心到底面的距离和进动角的估计,仿真结果表明了此算法的有效性。
[Abstract]:Fretting refers to the vibration, rotation and acceleration motion of the target or its components except the translational motion of the center of mass. The micro-motion will produce Doppler modulation effect on the radar echo, and this modulation effect is called micro-Doppler modulation. However, the micro-Doppler features can reflect the electromagnetic scattering characteristics, geometric structure and motion characteristics of the target, which has become an important feature of ballistic missile target classification and recognition in recent years. In this paper, the problem of micro-Doppler extraction and parameter estimation of spatial smooth conical target is studied. The micro-Doppler modulation of echo from fretting is studied. The micro-Doppler extraction of echo and the estimation of moving and structural parameters of the precession target are studied in this paper. The main contents of this paper can be summarized as follows: 1. The scattering characteristics and occlusion effect of smooth cone target are analyzed and the equivalent scattering point model of smooth cone target is established. Taking the linear frequency modulated (LFM) signal as an example, the Doppler modulation effect of precession and nutation on target radar echo is analyzed, and the mathematical form of instantaneous micro-Doppler frequency is deduced in detail. Finally, the correctness of the theoretical analysis is verified by simulation experiments. For the spatial conical object with smooth surface, a method of extracting micro-Doppler frequency based on linear frequency modulation (LFM) signal parameter estimation combined with random sampling consistent (RANSAC) algorithm is proposed. This method does not directly pre-model the fretting characteristics, but approximates the echo segmented signal as the superposition of the LFM signal components corresponding to several scattering points, and estimates the modulation frequency and the initial frequency of each LFM signal. Then the random sampling consistency is used to fit the model to obtain the microDoppler frequency curves of different scattering points. The effectiveness and robustness of the algorithm are verified by simulation experiments. A method for estimating the precession parameters and structural parameters of a spatial precession cone target is introduced. The variation of instantaneous micro-Doppler frequency between the conical top and the cone-bottom scattering point under different radar line-of-sight angles is analyzed. The radar line-of-sight angle is estimated by solving the equation according to this variation relationship, and then the motion parameters and structural parameters of the target are estimated. The target height, the radius of the bottom surface, the distance between the center of the rotation and the precession angle are estimated. The simulation results show the effectiveness of the proposed algorithm.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：E927;TN957.51

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