高信噪比下的信号波达方向估计方法

自适应调零天线被应用于卫星通信和卫星导航领域，对于强干扰情况，方向图在干扰信号方向形成零陷，从而实现干扰抑制。利用自适应调零天线采用的功率倒置LMS自适应滤波算法，可以实现对信号的波达方向估计。新方法利用自适应调零天线实现过程中求得的权矢量，计算方向图，并把该方向图倒数定义为空间谱函数，该空间谱谱峰对应信号波达方向。观察空间谱图并对算法中的步长和信噪比进行分析，结果显示该方法可高分辨率地估计出DOA，并且步长越小，信噪比越大，估计误差越小。相对于已有的MUSIC谱估计方法，该算法无需进行信源个数估计，也无需进行信号协方差矩阵特征分解，实现更为简单。 

DOA Estimation Method of Signal in the Environment of High SNR

To achieve DOA estimation in the background of strong interferences, there was a novel methodology based on using the technology of adaptive nulling antenna. In the new methodology, the weight vector was obtained by LMS algorithm and power inversion standard firstly as what the nulling antenna did. Then the reciprocal of the antenna pattern was defined as the special spectrum, whose peak value was corresponding to the estimated DOA. Through observation of spectrum and data analysis of step sizes and SNRs in algorithm, the results showed that it could achieve DOA estimation, what’s more, the estimated error would be smaller when the step size was shorter and the SNR was larger.Compared with the existing MUSIC spectrum estimation method, the new strategy has less compute load, since it does not need to do the estimation for the number of signal and eigenvalue decomposition of covariance matrix.