基于斜投影算子的混合信号DOA估计算法

DOA Estimation Algorithm of Mixed Signals Based on Oblique Projection Operator

为了提高混合信号的波达方向(direction of arrival,DOA)估计精度并降低其阵列孔径损失,提出一种基于斜投影算子的高精度DOA估计算法.所提算法将混合信号中独立信号与相干信号分两个阶段进行估计,首先利用ESPRIT(estimating signal parameter via rotational invariance techniques)算法处理阵元接收数据的协方差矩阵,得到混合信号中独立信号的DOA估计值;而后利用斜投影算子去除混合信号中独立信号的信息,得到新的协方差矩阵;利用新得到的协方差矩阵的信号子空间进行去相干处理;最后结合ESPRIT算法计算得到相干信号的DOA估计值.仿真结果表明,相较传统的混合信号DOA估计算法,所提算法在低信噪比情况下以及信号入射间隔较小的情况下有较高精度,有效地降低了阵列孔径的损失.在不同的采样快拍数下,本文算法也表现出更强的鲁棒性.

In order to improve the DOA estimation accuracy of mixed signals and reduce array aperture loss,a high-precision DOA estimation algorithm based on oblique projection operator is proposed.The proposed algorithm estimates the independent and coherent signals of the mixed signals in two stages.Firstly,the covariance matrix of the data received by the array element is processed by the estimating signal parameter via rotational invariance techniques(ESPRIT),and the DOA estimates of the independent signals in the mixed signals are calculated.Then,the algorithm uses the oblique projection operator to remove the independent signal information in the mixed signals to obtain a new covariance matrix.The signal subspace of the newly obtained covariance matrix is used for decoherence processing.Finally,the ESPRIT algorithm is used to calculate the DOA estimates of the coherent signals.Simulation results show that the proposed algorithm has higher accuracy than traditional mixed signal DOA estimation algorithms in the case of low signal-to-noise ratio and small signal incidence interval,and effectively reduces array aperture loss.Under the condition of different sampling snapshot numbers,the proposed algorithm also shows stronger robustness.