基于误差分布的鲁棒性差分波束形成设计

Robust Design of Differential Beamforming Based on Error Distribution

差分波束形成算法由于具有小尺寸、高指向性、宽带恒定束宽等优点受到了广泛关注。传统的基于零点约束的差分波束形成算法在工程上实现简单,但受限于白噪声增益放大特性,在低频处鲁棒性性能较弱。针对此问题,提出了一种基于误差概率密度函数零点能量最小化的差分波束形成算法,通过引入导向矢量误差分布的先验信息,对零点能量的期望值进行最优化。仿真结果表明,在低频处改进算法的白噪声增益性能明显改善,进一步提升抗干扰性能,并且在波束方向的频响更平坦。

Differential beamforming has been paid much attention due to its advantages such as small size,high directivity factor,and frequency-invariant directivity patterns.The traditional design of differential beamforming based on null-constrained method is simple and easy to implement.However,this method is not enough robust especially at low frequencies because of the drawback of white noise amplification.To overcome this problem,an improved solution is proposed based on error probability density function and null energy minimum.With the knowledge of steering vector error probability density function,the expectation of the null energy is optimized.The simulation results show that compared with traditional methods,the proposed approach has high white noise gain,the robustness is improved at low frequencies,and the frequency response at the direction of beamforming is more flat.