研究了冲击噪声环境下相干信源波达方向(DOA)估计问题。在对称α稳定分布冲击噪声假设下,基于共变和分数低阶矩的MUSIC(即ROC—MUSIC和FLOM—MUSIC)方法不能用于相干信源DOA估计。本文首次将空间平滑思想应用于共变系数矩阵和分数低阶矩矩阵中,定义了新的前后向平滑共变系数矩阵和前后向平滑分数低阶矩矩阵,提出了两种新的适用于冲击噪声环境的相干信源DOA估计方法:基于前后向平滑共变系数矩阵的空间平滑(ROC—SS)算法和基于前后向平滑分数低阶矩矩阵的空间平滑(FLOM—SS)算法。理论分析表明,可以通过前后向平滑共变系数矩阵和前后向平滑分数低阶矩矩阵的特征分解来估计噪声子空间,从而实现对相干信源的DOA估计。论文还对提出的ROC—SS算法和FLOM—SS算法进行了性能对比分析。计算机仿真结果证明了ROC—SS算法和FLOM-SS算法的有效性和正确性。
This paper is concerned with the direction of arrival (DOA) estimation of coherent sources in impulse noise fields modeled as symmetric α stable (SαS) distribution. Robust eovariation (ROC) based MUSIC and Frational lower moment (FLOM) based MUSIC cannot be used to estimate the DOA under these conditions. New forward-backward smoothing (FBS) -eovariation matrices and FBS-FLOM matrices are first defined by applying the spatial smooting idea to eovaria tion matrices and FLOM matrices. Two new algorithms based on FBS-eovariation matrices and FBS-FLOM matrices are presented in the meantime. Theoretical analysis shows that noise subspaee can be estimated by the eigen-decomposition of FBS eovariation matrices and FBS-FLOM matrices so as to estimate the DOA of coherent sources in impulse noise. Moreover, performanee of two new algorithms is analyzed by comparison. Computer simulation results verify the correctness and effectiveness of the proposed methods.