In this article, an algorithm for accurately estimating the directions-of-arrival (DOAs) of mixed circular and noncircular signals with a nonuniform linear array is devised. Via applying coarray interpolation on the difference and sum coarrays, we first formulate two nuclear norm minimization problems to reconstruct an augmented covariance matrix and an augmented unconjugated covariance matrix, respectively. Based on the reconstructed matrices, we further build the extended covariance matrix in the coarray domain. Finally, we construct several spectral functions to successively estimate the DOAs of the nonstrictly noncircular, strictly noncircular, and circular signals. Unlike the existing schemes, the proposed algorithm can identify accurately circular, strictly noncircular, and nonstrictly noncircular signals. Numerical results demonstrate the superiority of the proposed algorithm over existing techniques.

中文翻译：

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使用非均匀线阵的混合圆形和非圆形源的 DOA 估计

在本文中，设计了一种算法，用于准确估计具有非均匀线性阵列的混合圆形和非圆形信号的到达方向 (DOA)。通过对差分和和分列应用分列插值，我们首先制定两个核范数最小化问题，分别重建增广协方差矩阵和增广非共轭协方差矩阵。基于重构的矩阵，我们进一步在coarray域中构建扩展协方差矩阵。最后，我们构建了几个谱函数来连续估计非严格非圆形、严格非圆形和圆形信号的 DOA。与现有方案不同，所提出的算法可以准确识别圆形、严格非圆形和非严格非圆形信号。