一种改进的可变对角加载自适应波束形成算法

A Modified Diagonal Loading Adaptive Beamforming Method

由于观测方向误差的存在,使得实际获得的方向向量与其理论值产生偏差,进而对各类自适应波束形成算法性能造成较大影响。为此提出一种有效的对角加载自适应波束形成算法,首先利用目标信号的方向向量在噪声子空间中投影最小的原理,对带有误差的方向向量进行校正,然后再使用可变对角加载原理求得对角加载因子,对实际获得的自相关矩阵进行对角加载后,形成自适应波束,从而很好地消除了方向向量误差造成的影响。算法能够有效克服目标信号对消现象,并具有良好的保形能力和快速收敛的特点。计算机仿真结果验证了这些优点。

The existing of look direction errors causes the real steering vector apart from the theoretical one, which leads to serious performance degradation in adaptive beamforming algorithms. In this paper, an efficient diagonal loading method is proposed for eliminating the steering vector error. At first, the theory, that the projection of the steering vector in the noise space is the minimum one, was used to calibrate the steering vector error. Then the covarlance matrix was diagonally loaded by the varying value for adaptive beamforming. The proposed method can not only avoid the target signal cancellation, but also preserve the beam pattern. Fast convergence is guaranteed as well. These advantages were investigated through a series of computer simulations.