中文说明：
“完全可增强”稀疏线阵入射多个不相关平面波的波达角方向(DOA)估计问题。在估计阶段之前确定了现有信号源(M)的数目，研究了在最大似然意义下DOA估计精度有效的条件。
English Description：
Direction of arrival (DOA) estimation of multiple uncorrelated plane waves incident on a "fully enhanced" sparse linear array. Before the estimation stage, the number of existing sources (m) is determined, and the condition of DOA estimation accuracy efficiency in the sense of maximum likelihood is studied.