基于时频分析的多目标盲波束形成算法  

A blind beamforming algorithm for multitarget signals based on time-frequency analysis

作　　者：刘亚奇[1] 刘成城[1] 赵拥军[1] 朱健东 

机构地区：[1]解放军信息工程大学,导航与空天目标工程学院,郑州450001 [2]63880部队,洛阳471003

出　　处：《物理学报》2015年第11期245-255,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61401469)资助的课题~~

摘　　要：针对现有盲波束形成算法适用范围较窄,多目标信号分离级联模式结构复杂、并联模式稳定性较差等问题,提出一种基于时频分析的多目标盲波束形成算法.该算法首先利用时频分析技术给出信号导向矢量的不确定集,然后优化求解导向矢量的最优估计,最后利用Capon方法实现多目标信号的并行输出.理论分析及仿真结果表明,该算法对信号特性没有特殊要求,适用性较广,性能稳定,且输出信干噪比高于其他盲波束形成算法,接近于最优Capon波束形成器.The existing blind beamforming methods are effective only under the condition that the source signals have some special statistical or structural characteristics. Additionally, the structure of cascade model is complicated and the stability of parallel model is poor when dealing with multi-target signals. To address these problems, a novel blind beamforming algorithm for multi-target signals based on time-frequency （TF） analysis is proposed in this paper. The received array signals are first transformed into time-frequency domain by using quadratic time-frequency distributions （TFDs）. Then, the single-source auto-term TF points which show energy concentration at a single signal are extracted through three operations： （i） removing noise points by setting a reasonable threshold, （ii） separating auto-term TF points from cross-term points, and （iii） selecting the single-source auto-term TF points from the auto-term ones. Moreover, these single-source auto-term TF points are classified by the principal eigenvector of their spatial time-frequency distribution matrixes. For each class of TF points, the uncertain set of signal steering vector is given, whose radius is defined as the ultimate range between the center and the elements in the class. Within the uncertain set, an optimization algorithm is provided to get the optimal estimation of the signal steering vector. Finally, the blind beamforming for multi-target signals is achieved based on the Capon method, which can enhance the desired signals and suppress the noise and interference signals. In addition, the influence of parameters selection, the clustering method of unknown source number, and the computational complexity of the proposed algorithm are analyzed. The proposed algorithm can achieve parallel output of multi-target signals under the condition that the array manifold and the direction of arrival （DOA） are unknown. Also, the complex iterative solving processing may be avoided and special limitations on signal characteristics are

关 键 词：时频分析 盲波束形成 导向矢量最优估计 

分 类 号：TN911.7[电子电信—通信与信息系统]