任意几何形状和阵元指向性的传感器阵列优化波束形成方法

针对常规波束运用到实际传感器阵列时旁瓣较高这一缺点,提出了适用于任意几何形状和阵元指向性的传感器阵列的两种旁瓣约束优化波束形成方法。一种是主瓣宽度约束条件下的最低旁瓣波束形成,另一种是在所能允许的最高旁瓣约束条件下的高增益波束形成。通过对加权向量范数进行约束,提高波束形成的稳健性。这两种优化波束形成问题都可以写成二阶锥(Second-OrderCone)约束优化的形式,然后利用已有的内点方法(Interior-PointMethods)求出其数值解。计算机仿真和湖上实验数据处理结果表明,该低旁瓣波束形成方法相比于常规波束和其它基于自适应波束形成的旁瓣控制方法,在同等主瓣宽度的情况下可以获得更低的旁瓣级;该高增益波束形成方法在同等旁瓣级约束条件下可以获得更高的阵增益,而且旁瓣级能够满足设定要求。

Beampattern optimization for sensor arrays of arbitrary geometry and element directivity

Two optimal beamforming approaches for sensor arrays of arbitrary geometry and element directivity are developed. The first one minimizes the sidelobe level while keeping the distortionless response in the direction of desired signal and maintaining the mainlobe width. This approach can obtain lower sidelobe level compared to other adaptive-based low-sidelobe beamforming algorithms while keeping the same beamwidth. The second approach maximizes the array gain while keeping mainlobe direction and controling the maximum sidelobe level which is strictly guaranteed to be lower than a prescribed value. The approach can obtain higher array gain compared to the adaptive-based low-sidelobe beamforming algorithms while keeping the same sidelobe level. Array weight norm constraint is used to increase the robustness of the two optimal beamforming against random errors. Both of the optimal beamforming problems are converted to a convex form as the so-called second-order cone programming and easily solved using well-developed interior-point methods.Resultsof computer simulation and lake-experiment for a circular array show superior performance of the proposed approaches developed in this paper in comparison to the existing adaptive-based algorithms.