【作者】 杜晓玉；

【导师】 刘先省；

【作者基本信息】 河南大学 ， 应用数学， 2006， 硕士

【摘要】 在雷达信道中,不可避免地存在着噪声和干扰,它们通过天线方向图的边波束或主波束进入接收系统,从而降低系统的接收信噪比。随着天线技术的发展,自适应天线应运而生。自适应天线能自动地对干扰信号做出反应,将天线波束零点对准干扰方向,同时保持信号方向的接收能力。线形阵列和圆形阵列是自适应天线中最常见的两种阵列。线阵只能有180°的扫描范围,而圆形阵列能够提供360°方位角,通过循环移动阵列激励,简单而灵活地操纵波束的方位,能够在方位上产生没有方向性方向图,而在俯仰方向上也有一个理想的方向特性。本文分析了圆形阵列的性能,在此基础上应用了不同的算法;利用模式转换将圆形阵列转化成为虚拟的线阵,并且分析了共形天线的方向图函数。本文主要完成的工作:1.推导圆形阵列和线形阵列方向图综合函数,根据仿真结果分析并比较了圆阵和线阵的性能和特点,并在此基础上分析了幅相量化在阵列信号处理中产生的影响。2.对采样协方差阵求逆(SMI)算法进行了分析和研究,并将算法应用到圆阵的信号处理中。根据仿真结果比较了SMI算法和G-S算法的特点。3.利用Gerschgorin圆盘定理,估计出干扰的信号源数。并在此基础上,应用G-S算法,减少了漏警的可能性。4.利用模式空间变换将均匀圆形阵列转化成虚拟的均匀线阵,解决了圆形阵列副瓣电平较高(相对于主瓣)、零点深度相对较浅的问题。并在此基础上,应用G-S正交化算法、SMI算法和自适应旁瓣对消,计算并仿真了这几种算法的阵列方向图。5.用向量法严格分析了以相控阵为基础的共形天线的综合方向图函数,并推导出面阵天线、圆柱天线和圆锥天线的具体的方向图函数。更多还原

【Abstract】 Noise and interference are inevitable in radar channel. They enter the received system through side or main beams, and reduce the system’s receiving signal-to-noise ratio (SNR). With the development of the technology of antenna, adaptive antenna emerges as time requires. Adaptive antenna can react to interfering signal automatically, form the beam zero points at interference and keep the signal receptions in right directions.Linear array and circular array are the two commonest types in adaptive antenna arrays. Linear array can only provide an azimuth scan ranging from 0 to 180 degree, while circular array from 0 to 360. By means of recurring moving array excitation, circular array controls the beams’orientation simply and neatly, creating a perfect pattern in azimuth and an ideal pattern in pitch. This thesis analyzes circle array’s performance and employs different arithmetic accordingly; transforms circle arrays to line arrays by mode transform; analyzes the space geometry antenna’s pattern function. The main tasks finished in this paper include:1. This thesis deduces circular arrays and line arrays pattern’s synthesis function and compares their performance and characteristics according to simulation results. Also the influence of amplitude and phase quantification is analyzed in array signal.2. SMI algorithm is analyzed and researched when being applied in array signal processing. Characteristic comparisons between SMI algorithm and GS algorithm are compared according to the simulation results.3. Estimation about the number of the disturbances is done by means of Gerschgorin disk theorem, which is also employed to reduce the G-S algorithm false dismissal possibility basing on the former estimation results.4. Problem of circular array’s high side-lobe (relative to main-lobe) and the lower depth of zeros is resolved using mode space transform, which changing uniform更多还原