基于投影矩阵搜索的相干源DOA估计算法

在强相关或相干信号源环境下，基于子空间分解的高分辨方法无法准确估计信号到达角，而许多传统的解相干方法，如空间平滑法等，会减少阵列的有效孔径，且只适用于具有移不变性的阵列结构。针对相干信源DOA估计问题，提出了一种基于投影矩阵搜索的DOA估计算法。首先根据阵列流型构造噪声子空间的投影矩阵，并将阵列接收信号投影到噪声子空间；然后通过遍历搜索所有可能的投影矩阵获得空间谱，进而得到相干源的DOA估计。该算法能有效进行相干信源DOA估计，与传统的相干源DOA估计方法相比，该算法不会减小阵列的有效孔径，且适用于任意阵列结构，并具有良好的估计精度和超分辨能力，但计算复杂度较高。通过仿真实验，验证了该算法的有效性，比较了该算法与传统算法的性能。

DOA estimation algorithm for coherent signal sources based on projection matrix search

For strongly correlated or coherent signal sources, the high-resolution methods based on subspace decomposition can not accurately estimate signal direction of arrival. While most decorrelation algorithms, such as spatial smoothing, will reduce the efficient aperture, and is only suitable to the array structure with shift-invariance. A new DOA estimation algorithm based on projection matrix search is proposed for coherent sources. Firstly, the projection matrix of the noise subspace is constructed, which is based on the array manifold, and then the array received signal is projected into the noise subspace. Secondly, the spatial spectrum is calculated by searching all possible projection matrices, thus the DOA estimation of coherent sources is obtained. The proposed algorithm can effectively estimate the DOA of coherent sources. Compared with the conventional DOA estimation method for coherent sources, the proposed algorithm will not reduce array aperture, and can be applied to any arrays, and possesses better estimation accuracy and super-resolution capability, but the computational complexity of the proposed algorithm is higher. Simulation results show the effectiveness of the proposed algorithm and its superior performance over conventional algorithms.