Sparse arrays can increase the array aperture and degrees of freedom through the construction of either sum or difference co-arrays or both. In order to exploit the advantages of sparse arrays while estimating directions of arrival (DOAs) of a mixture of circular and non-circular signals, in this paper, a gridless DOA estimation method is proposed by employing a recently introduced enhanced nested array, whose virtual arrays have no holes. The virtual signals derived from both sum and difference co-arrays are constructed based on atomic norm minimization. It is shown that the proposed method also works when the circular and non-circular signals come from the same set of directions. Simulation results are provided to demonstrate the performance of the proposed method.

稀疏阵列可以通过构建和或差协同阵列或两者来增加阵列孔径和自由度。为了利用稀疏阵列在估计圆形和非圆形混合信号的到达方向 (DOA) 时的优势，本文提出了一种无网格 DOA 估计方法，该方法采用最近引入的增强嵌套阵列，其虚拟数组没有孔。从和和差协同阵列导出的虚拟信号是基于原子范数最小化构建的。结果表明，当圆形和非圆形信号来自同一组方向时，所提出的方法也有效。提供了仿真结果来证明所提出方法的性能。