基于空间二次投影的测向算法

DOA algorithm based on spatial secondary projection

在传统波达角估计(DOA)算法中,子空间拟合类算法由于具有分辨率高、测向精度高等特点而被广泛应用。但该类算法在测向时需要预知准确的信源数量,否则将严重影响算法性能。针对在信源数量未知条件下的高精度测向问题,提出了一种基于空间二次投影的测向算法。该算法首先通过向量到空间的投影关系构造一次投影空间谱,再利用空间完备基对空间内向量描述的唯一性进行第二次投影,排除可能出现的伪方位角谱峰,完成波达角估计。计算机仿真结果表明,基于空间二次投影的测向算法无需预知信源数量即可实现对相干信源方位角的准确测算,且该算法在小孔径、少快拍条件下仍然具有较高的空间分辨率及算法稳定性。

In conventional DOA methods, the subspace fitting algorithms have been widely used for its high resolution and high estimation accuracy. However, when subspace algorithm works, it needs to predict the exact number of sources, otherwise the performance of the algorithm will be seriously affected. In the view of the problem of high precision direction-finding under conditions where the number of signals is unknown, a DOA algorithm based on spatial secondary projection is proposed. Firstly, this algorithm constructs the primary-projection spatial spectrum by the relationship between vector and its spatial projection. Secondly, it takes a secondary-projection to removes the possible pseudo-peaks by taking the advantage of the uniqueness of the vector representation by complete spatial vector basis. The computer simulation results show that the spatial secondary projection algorithm can realize the accurate measurement of the coherent signals’ DOA without predicting the number of signal sources, and this algorithm has high spatial resolution and algorithm stability under the conditions of small aperture and limited number of snapshots.