从阵元域到模态域阵列信号处理

From element-space to modal array signal processing

阐述了模态域阵列信号处理技术。以球面阵为例,从阵元域信号处理基础出发,推导了对应的模态域阵列信号处理表达式,其中重点推导了模态域波束形成器与时域宽带波束形成器设计及其实现方法,设计实例验证了方法的有效性。结果表明模态域处理与经典的阵元域处理具有相似的形式,因此可以将比较成熟的阵元域算法推广到模态域。相比于阵元域处理,模态域处理对声场传播与信号处理的结合更紧密,模态域波束形成具有能将波束导向与波束图综合解耦处理,以及减少信号处理通道数等优点。但模态域阵列信号处理技术适用范围也有限,仅适用于能够将声场进行谐波分解的阵形,如球面阵和圆柱阵等。

Modal array signal processing technique, which is based on the principles of wave propagation and wave scattering, are presented in this paper. The derivations of modal array signal processing algorithms for both frequency- domain and time-domain broadband beamformer are discussed. Results of simulations show good performance of the modal array processing algorithms. Using the similar process technique, other modal array signal processing algo- rithms can also be derived. The modal beamforming approach is computationally more efficient compared to a classical element-space array processing because the number of signal processing channels is reduced and the look direction of the beamformer can be tactfully decoupled from its beampattern shape. However, the modal array processing technique can only be applicable to symmetrical arrays such as spherical arrays and cylindrical arrays.