基于微多普勒的锥体目标进动和结构参数估计

Precession and structural parameter estimation of cone-shaped target based on the micro-Doppler

真假目标识别是弹道导弹防御的一大技术瓶颈,目标识别的正确与否在一定程度上决定了反导系统的成败.微动引起的雷达可观测量微多普勒特征包含了目标的运动、尺寸、形状等大量信息,因此微动特征是当前学术界公认的弹道中段目标识别的有效特征之一,对微动特征的提取为弹道导弹防御目标识别提供了新的解决手段.该文以旋转对称锥形目标为研究对象,根据散射中心理论以及攻防对抗条件,推导了目标两个等效散射中心的位置与回波模型,建立了基于滑动型散射中心的锥体目标进动模型.分析了目标的结构参数与雷达回波微多普勒参数的显式关系,推导出微多普勒随时间变化的解析表达式.结合弹道中段目标识别等应用背景,提出了基于TFDHough变换的联合参数估计的方法.该方法综合两个散射中心的微多普勒参数,联合求解二者的参数空间,对进动和结构参数进行估计.仿真结果表明目标回波的微多普勒时频曲线与解析微多普勒曲线吻合,所提联合参数估计方法可准确估计进动角、进动频率、锥体高度、锥底半径等进动和结构参数.

The discrimination of warhead and decoys is one of the main technological bottlenecks in ballistic missile defense system,which means the success or failure of the anti-missile system to some extent.Micro-motion is commonly referred to small mechanical vibrations or rotation in addition to mass translation which may induce additional frequency modulation on the received target echoed signal,called micro-Doppler effect.The characteristic of micro-motion is academically considered as one of the most effective characteristics in ballistic midcourse target recognition.The extraction of the micro-motion characteristics offers new measures for target recognition in ballistic missile defense.And in the many recognition methods,the one based on the micro-motion plays the most important part.Using target micro-motion characteristics for target detection and recognition is a hot topic in radar community recently.This paper obj ects at the midcourse rotational symmetrical cone-shaped target.In this paper,under the background of missile confrontation,the location and model of echo of the two scattering centers on the target are＆amp;nbsp;derived and the model of precession of cone-shaped target with sliding scattering center is constructed according to the scattering center theory.The explicit relationship among the structure parameters and the micro-Doppler parameters is analyzed and then the analytical expressions of micro-Doppler are derived.The time frequency distribution-Hough（TFD）transformation is a commonly used method for the parametric estimation of frequency modulated signal,its core being the accurate signal modeling and to design the algorithm of extracting the time-frequency curve according to the frequency changes of signal.In the paper,the parametric estimation method by using the tool of TFD-Hough transformation is studied.Then a joint parameter estimation method based on TFD-Hough Transform is proposed,under which precession and structural parameters are estimated according to the syn-thesized micro-Doppler parameters of two scattering centers and joint solutions of their parameter space.Simulation results show that the time-frequency curves of micro-Doppler echo coincide with the analytical expression.The joint parameter estimation method introduced can be referred to accurate estimation of precession and structural parameters such as precession angle,precession frequency,cone height,conical bottom radius,etc.