中文摘要：

在阵元数目一定的情况下，为了扩大阵列的孔径，本文采用非均匀稀疏对称阵列，其阵元间距不受四分之一载波波长的限制．为了避免由此带来的角度模糊问题和复杂的二维搜索，本文基于降秩思想，提出了近场源波达方向（DOA，Direction Of Arrival）和距离的无模糊估计方法并且分析了角度估计的模糊性．此方法利用二阶统计量，只需进行一维搜索，且参数自动配对．因此，计算量大大地减少，且在阵元个数有限的情况下，大大地提高了空间分辨率．计算机仿真结果证实了此方法的有效性．

英文摘要：

In order to enlarge the array aperture in the case of having determinate number of sensors, this paper utilizes a sparse symmetric array which allows the inter-element spacing to exceed the quarter-wavelength upper limit. To avoid the direction- of- arrival （DOA） ambiguity and complicated 2- D search, a method based on rank reduction（RARE） has been presented for estimating the DOA and range of near-field soutces without ambiguity.And the ambiguity of DOA estimation is analyzed. The algorithm utilizes second-order statistics and only requires 1-D search,and all parameters are automatically matched. Therefore the computational burden is reduced and the spatial resolution is enhanced when the number of sensors is limited. Simulations are included to show the validity of this proposed method.