在阵列测向问题中应用高阶累积量除了信息利用更充分和抑制高斯噪声等优点之外还具有阵列扩展的功能.本文推导了基于四阶累积量的阵列扩展方法,研究了虚拟阵的结构.放宽了协方差方法对信源数目的限制.但该方法在窄带多信号方向估计应用中存在局限.本文还推导了四阶相干问题和阵列扩展的限制条件.最后给出了实验举例. The application of high-order cumulants in array direction finding has the function of array expansion in addition to the advantages of more complete use of information and suppression of Gaussian noise, etc. In this paper, the method of array expansion based on fourth-order cumulants is deduced and the structure of virtual array The restriction of the covariance method on the number of sources is relaxed, but the method has some limitations in the application of narrowband multi - signal direction estimation.The fourth order coherence problem and the limitation of array expansion are also deduced.The experimental examples are given finally.