解到达角估计模糊的二次虚拟阵列变换

引入非均匀时延构造虚拟阵列变换的变换矩阵，提出一种基于二次虚拟阵列变换的到达角估计方法. 该方法利用非均匀时延间隔的随机性，每一次快拍下都等效于随机改变虚拟阵元的阵元间隔，突破了空域采样定理的限制，解决了在使用较大阵元间距条件下到达角估计的模糊问题. 同时增大的阵元间距也提高了估计的精度和分辨力. 进一步的实验表明，该方法是可行的、有效的，且能改善小信噪比条件下的估计精度.

Twice Virtual Array Transformation for Overcoming Direction-of-Arrival Estimation Ambiguity

A new approach is proposed for resolvingthe directionambiguity by using twice virtual array transformation, which makes use of the nonuniform time delay to generate virtual transformation matrix. Due to the random variation in time interval of nonuniform time delay, the transformation based on nonuniform time delay matrix is equivalent to altering the relative distance between sensors. This means that the plane wave impinges a virtual uniform linear array with a time-varying array element interval. Therefore, a larger array aperture is available without anglular ambiguity, which enhances resolution and accuracy of the direction-of-arrival (DOA) estimation. Simulation results show that the proposed algorithm is effective for DOA estimation, and capable of improving estimation performance at low SNR.