基于加权子空间投影的谱估计器分辨力研究

针对常规子空间类算法在低信噪比、小快拍数情况下分辨力差的问题,分别对信号和噪声子空间提出加权投影算法来加以改善。对于信号子空间,采用主特征值与噪声功率之差的倒数对其特征向量加权；对于噪声子空间,将导向矢量在噪声子空间正交基各元素上的投影值作为权值,对正交基各元素加权。仿真实验表明,这两种算法能有效降低信源分辨的信噪比和快拍数门限,在低信噪比与小快拍条件下具有较好的分辨力和测量精度。

Improving Resolution Ability of Spectral Estimator by Weighted Subspace Projection

In order to improve the decreasing resolution ability under the environments like low signal noise ratio and small number of snapshots,two weighted projection methods were proposed respectively to signal subspace and noise subspace.The weighted values of signal subspace are reciprocal of margins between principle eigenvalues and noise power,and respective eigenvectors are weighted with them.To noise subspace,the elements of orthonormal basis are weighted with projection values which are gained by projecting integral value of steering vector in field of view to each element of orthonormal basis.Simulation results show that the proposed methods can decrease signal noise ratio threshold and snapshots threshold,so they have better resolution ability and higher precision in deficient snapshot and low signal noise ratio scenario.