抗导向矢量失配的零陷展宽波束形成算法

Null broadening beamforming against steering vector mismatch

摘要:

针对自适应波束形成器在干扰出现扰动或期望信号导向矢量失配时，性能急剧下降的问题，提出一种抗导向矢量失配的零陷展宽波束形成方法.首先通过投影变换技术对阵列接收数据进行投影预处理，构造一个新的协方差矩阵, 以扩展干扰入射角度，展宽零陷；再根据期望信号入射的大致方位，对波束主瓣进行幅度响应约束，在约束区域形成稳定的响应幅度，达到抗导向矢量失配的目的.该方法可以转化为松弛半正定规划问题进行求解.仿真结果表明：该方法能有效展宽波束的零陷宽度，加深零陷深度，同时具有良好的抗期望信号导向矢量失配的能力，提高了自适应波束形成器在复杂环境下的稳定性.

Abstract:

Since adaptive beamforming suffers from output performance degradation in the presence of interference nonstationarity or signal steering vector mismatch, a new robust null broadening technique is proposed. The proposed method can pre-process the array received data by projection transform technique to get a new covariance matrix, so the interference incident angle is extended and the null is broadened. Then, magnitude response constraints are applied on general location of the desired signal. The proposed method forms a stable magnitude response in the constraint region against the steering vector mismatch. The proposed method can be solved by converted it into a Semi-definite Relaxation programming. Simulation results show that the proposed method can effectively broaden the beam null width and enhance the null depth, which can suppress strong interference with fast motion and has high ability against steering vector mismatch. The robustness of beamformerhas been significantly improved due to the proposed method in complex situations.