非线性约束的自适应波束形成算法

提出基于非线性约束的自适应波束形成算法. 首先修改接收信号协方差矩阵信号子空间中的特征向量,使修改后的协方差矩阵基本不包含期望信号(SOI)成分而只包含干扰信号和噪声. 进而利用线性约束最小均方算法(LCMV)和修改后的波束空间求解方向图的权向量w. 为了提高算法的稳健性,采用非线性约束方法对w进行优化,w的优化解在形式上不同于可变对角加载类算法,且优化解中的待定参数容易准确求出. 新算法的输出信干比 (SINR)对导引向量随机误差具有稳健性, 并对期望信号的功率变化表现出不敏感的特性, 仿真证明了这一点.

The Adaptive Beamforming Algorithm with Nonlinear Constraint

An adaptive beamforming algorithm based on nonlinear constraint was presented.Firstly,the algorithm modified the eigenvectors corresponding to signal subspace of the covariance matrix of the receiving signals.SOI(signal of interest) was not contained in the modified covariance matrix but interference signal and noise were contained.Then LCMV(linearly constrained minimum covariance) method and the modified covariance matrix were adopted in the new approach to obtain weight vector of adaptive pattern.To improve the robust characteristics,nonlinear constraint method was used to optimize the weight vector of adaptive pattern.The final solution of weight vector was different from alterably diagonal loading and the unknown parameter in optimal solution can be obtained easily and accurately.The SINR(signal to interference plus noise ratio) of the new algorithm has robust characteristics for random steering vector errors and is not sensitive to power change of SOI.Simulation results prove the validity of the new algorithm.