聚焦的子空间正交性测试宽带DOA估计方法

Focused Test of Orthogonality of Projected Subspaces for Wideband DOA Estimation

投影子空间正交性测试法(Test of Orthogonality of Projected Subspaces,TOPS)是利用宽带信号多个频点的子空间的正交性完成波达方向(Direction of Arrival,DOA)估计。该方法依赖参考频率点的选择,易产生伪峰,且在低信噪比时性能差。针对该问题,提出一种聚焦的FTOPS算法。首先利用RCM(Reduced Covariance Matrix)法消除了噪声,然后将各个频点的信号子空间(Signal Subspace)聚焦到任意参考频点的Signal Subspace,利用该参考频点的Signal Subspace与阵列方向矢量的正交投影矩阵之间的正交性完成DOA估计。仿真结果表明,该方法不依赖于参考频点的选择,能有效消除伪峰,在低信噪比条件下性能优于传统TOPS算法。

The test of orthogonality of projected subspaces （TOPS） utilized the orthogonality of subspace of multiple fre- quency points of wideband signal to complete the directions of arrival （DOA） estimation. The performance of TOPS was poor at low signal-to-noise ratio, and depended on the choice of reference frequency point. Besides the TOPS often exhibi- ted pseudo-peak. This paper proposed a modification （FTOPS） based on the idea of focus to overcome the shortcomings of TOPS. Firstly, the method of reduced covariance matrix （RCM） was utilized to eliminate the noise. And then the signal subspace at each frequency point was focused on the signal subspace of any reference frequency. Finally, the DOA estima- tion was completed using the orthogonality between the signal subspace of the reference frequency and the orthogonal projec- tion matrix of the array direction vector. The simulation results show that the FLOPS does not depend on the selection of ref- erence frequency, and can effectively eliminate the pseudo peak, and the performance of FTOPS is superior to the tradition- al TOPS algorithm at low SNR.