一种改进的空间平滑算法

空间平滑是一种有效的解相干算法。但是当相干信源相距很近时，传统的空间平滑算法性能明显下降。该文提出一种改进的空间平滑算法。该算法首先将子阵输出的自相关矩阵进行互相关，然后将前后向互相关矩阵平均后的协方差矩阵作为修正后的空间平滑矩阵进行空间谱估计。文中给出了该算法的表达式，分析了算法的性能。仿真结果证明该算法与传统算法及利用子阵协方差算法相比具有更高的分辨能力和更低的信噪比门限。

An Improved Spatial Smoothing Technique

Spatial smoothing techniques are effective to estimate the directions of coherent arrivals. The performance of these techniques deteriorates rapidly as the coherent arrivals become closely spaced. In this correspondence, an improved spatial smoothing technique is proposed. The algorithm makes cross-correlation of all auto-correlation matrixes of subarray output, and then takes the spatial spectrum estimation to the equivalent spatial smoothing matrix after the forward and backward correlation matrixes averaged. The formula for the algorithm is derived, and the performance of the algorithm is also analyzed. Simulation results demonstrate that the improved algorithm possesses a better resolving ability and a lower SNR threshold than conventional SS technique and subarray-covariance SS technique for DOA estimation of coherent signals.