用于水声通信的宽带波束形成结构

New Wideband Beamforming Method Used in Underwater Communication System

提出一种用于水声通信中的基于复数系数有限冲激响应(FIR)滤波器的宽带恒定束宽波束形成结构。其中,各阵元接收信号首先通过时间延迟线补偿整数倍采样间隔时延,接着通过频带搬移得到接收信号的复包络,最后采用复数系数FIR滤波器实现对不同频率信号复包络的加权,复数系数FIR滤波器的系数由最优化方法设计得到。仿真结果表明:采用基于复数系数FIR滤波器的宽带恒定束宽波束形成结构,在通信带宽与载波频率的比值约为0.85时,设计得到的宽带波束与期望值间的最大误差小于0.3 dB.

A novel wideband beam forming structure with constant width based on finite impulse response（FIR） digital filter with complex coefficients used in underwater acoustic communication is proposed.First,the complex envelopes of the received signal are calculated by using frequency shift method.Then,they are weighted by FIR digital filters with complex coefficients.The coefficients of these filters are obtained by using second order optimization method.The simulation results show that,in the communication band,the maximum difference between the wideband beams obtained by the proposed beam forming structure and the expected value is less than 0.3dB when the ratio of communication band to the carrier frequency is 0.85.