基于主模式抑制的主动稳健自适应波束形成方法

A Robust Adaptive Beamforming Method for Active Sonar Based on Dominant Mode Rejection

针对主动声纳发射信号持续时间短、信道复杂多变引起的自适应处理效果较差问题,通过声场空-时特性研究,提出基于主模式抑制的主动稳健自适应波束形成方法(Steered Dominant Mode Rejection,ST-DMR)。首先,该方法利用主动信号宽带频率相干性对协方差矩阵作预导向处理,提高收敛速度;然后,实施矩阵特征分解,确定出主模式子空间及其特征值;其次,以保护因子作信号方位失配保护处理,修正权值计算,从而得到波束形成的时域输出和空间谱估计结果。数值仿真与海上试验数据分析表明,ST-DMR保护能力。

Due to the short duration of active signal in complex multivariate acoustic channel, the performance of adaptive beamforming on active sonar is deteriorated. A robust adaptive beamforming method based on dominant mode rejection (ST-DMR) is proposed by utilizing the space-time characteristic on acoustic field. Firstly, in this method, the covariance matrix is pre-guided by the broadband frequency coherence on active signal, and the convergence speed is improved. Then, with covariance matrix eigen decomposition, its dominant mode subspace and eigen-value is obtained. Lastly, a protection factor is used to angle mismatch protect, and then the weight vector is modified to achieve the adaptive beamforming process. Simulation and experimental data analysis show that ST-DMR method achieves high resolution and low sidelobe level, convergence quickly, process robust and mismatch protect.