对角加载对信号源数检测性能的改善

Performance Improvement of Source Number Detection Using Diagonal Loading

对角加载技术可抑制小特征值对自适应权值的影响来加速自适应波束形成器的收敛性以及抑制导向矢量误差的影响避免信号相消 ,该技术通常用于稳健的波束形成算法 .基于对角加载技术 ,本文提出了一种信号源数目判定的改进方法 ,通过对角加载数据协方差阵 ,可以平滑小快拍数和空间色噪声时的噪声特征值分散程度从而减轻其对信号源数目估计的影响 ,证明了该估计器的强一致性 ,分析了加载量对信号源数目估计的影响 .最后通过仿真以及实测数据比较了本文方法和已有方法的性能 。

Diagonal loading is generally used in robust beamforming to reduce the effects of small eigenvalues and the steering vector error so as to improve the convergence of adaptive beamformer and avoid signal cancellation. We prove that the effect of small eigenvalues on the estimation of source numbers can be reduced by diagonally loading the corresponding correlation matrix, and the performance of the methods for determining the number of sources impinging on a sensor array can be improved. Furthermore, the strong consistency of the associated estimator is proved, and the effect of the loading value on the estimator is analyzed. Computer simulation results and the available measured data confirmation show that the diagonal loading is effective to the performance improvement of the estimators.