傅立叶-勒让德级数展开的宽带聚焦

Broadband focusing using Fourier expansion

提出了一种新的直线阵的宽带聚焦变换矩阵的设计方法。该方法把直线阵的阵列流型用以勒让德多项式为基的傅立叶级数展开形式表示,并将高阶项截断,同时对聚焦矩阵加以约束从而保证无聚焦损失。由此解得的聚焦矩阵不受阵列尺寸和阵元间距的限制,无需预估波达方向(DOA)或预置目标所在扇区,而且对不等间距的直线阵同样适用,海上试验证明聚焦算法的实用性和有效性。

A new method of broadband focusing matrix design for linear array is proposed in this paper. In the method, the array manifold is expanded in the form of sum of an infinite series, which is based on Fourier-Legendre polynomial expansion. The high terms of the series are truncated, and the focusing matrices are banded to ensure that the loss of the focusing is none. The resolution from the new method can be performed without the limitation of the array size and sensors＇ interspaces. Furthermore, there is no need to get the preliminary DOA estimations or preset some sectors within which the targets are assumed to lie. The method can be used in the unequally spaced linear arrays process, and has been proved the effectiveness in the sea trials.