基于多分辨率复合阵列的未知信源数波达方向估计

Direction-of-Arrival Estimation for Multi-resolution Composite Arrays with Unknown Source Number

为解决信源数未知情况下的多分辨率复合阵列波达方向(DOA)估计问题,将未知信源数的相干信号DOA估计算法拓展到多分辨率复合阵列中。本文研究了基于子阵空间谱联合的DOA估计方法,首先构造各个子阵列的托普利兹矩阵,并进行未知信源数的相干信号DOA估计;然后利用多分辨率复合阵互质的特性,构建联合代价函数进行解模糊。针对全范围搜索计算量大的不足,文中提出了单个不模糊区搜索,反推全部模糊角度的改进方案。仿真结果验证了所提方法的有效性,相比于全空间搜索的MUSIC算法和Capon算法,该算法无需信源数先验信息,且在信噪比大于15 dB和快拍数大于300时,其DOA估计的均方根误差仅为传统方法的1/2。

In order to solve the direction-of-arrival(DOA)estimation problem when the source number is unknown,the DOA estimation algorithm of coherent signals with unknown source number is extended to multiresolution composite arrays.The DOA estimation method based on sub-array spatial spectrum combination is studied in this paper.First,the Toeplitz matrix of each sub-array is constructed,and the DOA estimation of the coherent signals with unknown source number is performed.Then,the coprime character of the multi-resolution composite matrix is used to construct a joint cost function and solve the angle ambiguities.In order to overcome the shortage of large-scale searching calculation,an improved algorithm of searching single unambiguous area and deriving all ambiguous angles is proposed.The simulation results verify the effectiveness of the proposed method.Compared with the multiple signal characterization(MUSIC)algorithm and the Capon algorithm for full-space search,the improved algorithm does not need the prior information of the source number.When the signal-to-noise ratio(SNR)is greater than 15 dB and the number of snapshots is larger than 300,the root mean square error(RMSE)of the DOA estimation is only half of that obtained by the traditional method.