强背景下的微弱高精度目标定位算法

强背景下的微弱高精度目标定位算法摘要：目前，基于阵列天线的微弱信号检测和参数估计方法正在被广泛的应用于雷达、通信、导航、声纳、射电天文、生物医学工程以及地震探测等诸多军事及国民经济领域。由于实际工作环境复杂，阵列接收数据中经常是强干扰与微弱信号并存，常规的经典波达方向(DOA,Direction of Arrival)估计方法，如多重信号分类法(MUSIC)和旋转不变子空间法(ESPRITE)法就无法准确检测出微弱信号，导致系统对微弱信号的波达方向估计精度受到很大影响：已有的针对强干扰背景下微弱信号DOA估计问题的算法则大都基于一维线阵，少有涉及二维其它阵型的讨论。针对这些问题，本文所做的主要工作如下：首先，将目前已有的解决强干扰背景下微弱信号D0A估计问题的方法做了总结和归纳，并在传统经典算法MUSIC算法的基础上提出了两种新方法一一基于Householder变换的干扰阻塞法和修正投影阻塞法。(I)基于Householder变换的干扰阻塞法的基本思想是在强干扰来波方向已知或可准确估计的情况下，通过Householder变换构建干扰阻塞矩阵来对接收阵列信号做预处理，从而阻塞干扰达到准确估计微弱信号的目的：(2)修正投影阻塞法的基本思想是对阵列接收数据协方差矩阵进行特征分解后，由子空间理论得出干扰子空间，再构造干扰子空间的正交投影矩阵作为干扰阻塞矩阵，对接收阵列信号做预处理，从而达到抑制干扰的目的。也就是说，两种方法的相同点在于都是通过构造干扰阻塞矩阵的思想阻塞掉干扰，不同点在于构建阻塞矩阵的方法不同，且修正投影阻塞法不要求强干扰来波方向已知或可准确估计。本文在Matlab7.0的环境下分别对这两种方法进行了仿真实验和结果分析。其次，为了进一步说明这两种方法各自的特点和适用范围，以便于在实际工程应用中根据复杂的环境条件进行选择，本文依据各项评价指标（不同干扰个数、不同阵列模型、不同阵元数、不同强弱信号相距角度、不同阵列幅相误差等方面)对提出的算法进行了性能的分析和对比，实验结果表明，这两种算法均能够很好的解决被强干扰淹没的微弱信号的D0A估计问题，阻塞矩阵构建形式固定，且一维二维均适用。基于Householder变换的干扰阻塞法无需预白化处理，因此具有计算复杂度低的特点；修正投影阻塞法在快速阻塞干扰的同时不损失自由度，多个干扰同时存在的条件下估计性能依然良好。关键词：强干扰/弱信号，DOA估计，修正投影，Householder变换The Research of Weak Signal DOAEstimation in The Presence of StrongInterferenceAbstract:At present,the weak signal detection and parameter estimation method of arrayantenna technology is widely used in territory of military or national economy suchas:radar,communication,navigation,sonar,radio astronomy,biomedicine engineering andearthquake detection and so on.While,as the complexity of actual work environment,datumreceived by array antenna simultaneous existence of the weak expected signals and stronginterference signals,which lead to the estimation of classic DOA(DOA,Direction ofArrival)method,such as multiple signal classification(MUSIC)and rotation invariant subspacemethod(ESPRITE)method can not accurately detect the weak signal,thus the weak signaldirection of arrival estimation accuracy of the system is greatly influenced.To solve theseproblems,this paper makes the research as follows:Firstly,the method to solve the estimation problem of weak signals DOA estimation thatin the presence of strong interference is summarized,then the paper puts forward twoalgorithms -one is jam jamming method based on Householder transform,the other iscorrected projection jam method which based on the traditional classical MUSICalgorithm.(1)The basic idea of Householder transform is use the known or can be accuratelyestimated wave direction information construct interference blocking matrix to pre-treat thereceiving array signal,so as to estimate the weak signal accurately.(2)The basic idea ofcorrected projection jam method is by constructing feature decomposition of the arraycovariance matrix,use the subspace theory to find the interference subspace,and makeorthogonal projection matrix interference subspace as interference blocking matrix,thenpre-treat the received array signal,so as to achieve the purpose of suppressinginterference.That is to say,two methods that are all constructed by means of interferenceblocking matrix to block interference;but