改进的宽带阵元延迟线恒定束宽波束形成算法

Improved broadband frequency invariant beamforming algorithm with sensor delay lines

针对时域宽带恒定束宽波束形成计算复杂度高、硬件实现复杂等问题,提出基于离散空间响应变化(SRV)约束的宽带阵元延迟线(SDL)恒定束宽波束形成算法。该算法首先建立SDL宽带阵列模型,然后分别在有无强干扰的情况下,采用约束优化的方式,在保证期望来向增益趋于单位响应的同时,对期望方向逼近精度、旁瓣增益、主瓣宽度、SRV等进行约束,使得可能的最大旁瓣均值最小,最后将其转化为二阶锥规划问题,并利用内点法进行求解。实验表明,该算法的频率不变性较好,收敛速度较快,计算复杂度较低。

The design of frequency invariant beamformer （FIB） with tapped delay lines always suffers from heavy hardware load and high computational complexity. To alleviate this problem, a novel FIB algorithm with sensor delay lines （SDL） is proposed. Based on the SDL wideband model, the FIB design utilizes the constrained optimizing with and without interfering signals. The optimizing criterion of the proposed algorithm is minimizing the designed sidelobe level utmost while keeping the look direction response close to the unity response and the constraints of the sidelobe level, mainlobe width, spatial response variation （SRV） and so on. The constrained optimizing formula can be solved with interior-point method after being reformed to the form of standard second order cone programming （SOCP）. The simulations illustrate that the beampattern with the frequency invariance in the whole field of view can be obtained, the convergence speed of the proposed method is faster and the computational complexity is lower.