时变运动在MIMO系统中时延和多普勒频移耦合模糊的研究

项目名称： 时变运动在MIMO系统中时延和多普勒频移耦合模糊的研究

项目编号： No.61271351

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 无线电电子学、电信技术

项目作者： 桂任舟

作者单位： 同济大学

项目金额： 70万元

中文摘要： MIMO可灵活布置天线，减少发射功率；载波聚合形成大带宽可提高距离分辨率。在MIMO中使用载波聚合后存在距离和速度耦合模糊。时变运动时该模糊尤其严重：距离和速度分辨率下降，旁瓣干扰变强。时变运动需快速精确获取MIMO天线阵中各天线单元相位偏移，用于数字波束形成，以便模糊分析，本项目采用基于负随机的Hopfield神经网络来避免局部最小值，快速求出最优天线相移矢量矩阵；在载波聚合中的各频段碎片内采用相位幅度非均匀分布的线性调频信号，该信号的相位幅度在给定方差范围内随机变化，在MIMO各通道之间实现准正交，获得最佳时变运动的距离和速度模糊图，从而提高分辨率、压低旁瓣、减少干扰。以高频地波雷达为应用对象，进行系统改进，通过多站雷达和机动雷达获得大量基于MIMO的实测数据，比较改进前后距离和速度模糊图。通过长期大量的地波雷达实测数据分析，对距离与速度模糊分析的正确性和所提方法的可行性进行有效验证。

中文关键词： 线性调频；非连续频谱；模糊函数；旁瓣压缩；多进多出

英文摘要： The arrangement of antennas can be arbitrary in the MIMO system, with the advantage of relatively lower transmitting power in each antenna, while the carrier aggregation can improve rang resolution by aggregating a wide band. There exists ambiguity on rang-velocity coupling, especially in time-varying moving targets: the rang and velocity resolutions get low, and the sidelobes get high. When forming the beam for time-varying movement, the phase shifting of each antenna in MIMO antenna array should be acquired quickly and accurately. The Hopfield neural network based on negative random is applied to avoid local minimum and rapidly find the optimal antenna array phase vector matrix. In each fragment of frequency segment, we apply the linear frequency modulation (LFM) signals whose initial phase and amplitude are alternated randomly with the given variance. In this way, the quasi-orthogonality of different channels' signals can be ensured. We carry on the research on rang-velocity ambiguity, and analyze the corresponding sidelobes. Using this way, the resolution can be improved, the sidelobes can be reduced, moreover the disturbances can be suppressed. With the application in high frequency surface wave radar, we improve the performances of the radar system. Based on the data of MIMO system in multistatic radar and

英文关键词： Linear Frequency Modulation；Discontinuous Spectra；Ambiguity Function；Sidelobe Suppression；MIMO