传统宽带自适应波束形成算法在信号带宽较宽时硬件实现困难且形成零陷较窄.针对此问题,利用传感器延迟线阵列结构替代传统的时域抽头延迟线结构,在此基础上提出基于空间响应偏差约束的宽带零陷展宽波束形成方案.对参考频率干扰信号方向邻域的波束响应进行最大值约束,然后利用SRV约束将零陷展宽,通过凸优化工具求得最优加权向量.仿真结果表明,该算法可在保证波束宽度的同时实现宽带零陷展宽.在零陷宽度设定为10°、零陷深度为-30 dB的条件下,零陷宽度实测值可以达到14.7°,且具有较高的输出信干噪比.
Traditional adaptive wideband beamforming is difficult to be implemented with hardware, and has narrow null width in direction of interference. To deal with the problem, a novel null broadening wideband beamforming algorithm based on spatial response variation (SRV) constraint is proposed. Tapped delay-lines based systems are replaced with a structure based on sensor delay-lines (SDL). At the reference frequency, the beam response in the direction of interference is limited by using a maximum constraint. An SRV constraint based algorithm is used to broaden the region of nulls. An optimal weight vector is obtained using a convex optimization tool. Simulation results show that, with the proposed algorithm, null broadening and constant beam width can be realized at the same time of wideband beamforming. When null width is set to 10° and null depth is -30 dB, a measured null width of 14.7° can be obtained, and the system has a high output signal to interference and noise ratio (SINR).
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