摘要:
在理论上零均值高斯分布噪声的四阶累积量恒等于零,而实际噪声和混响的概率密度是影响四阶累积量波束形成技术性能的关键问题。本文针对海洋环境噪声与海底混响的瞬时幅度分布,分别推导了四阶累积量波束形成阵增益函数;建立了阵增益与阵元数、海洋环境噪声和海底混响统计特性的四阶矩和二阶矩及输入信噪比的关系;确定了与常规波束形成阵增益之间存在临界信噪比,高于临界信干比时四阶累积量波束形成可以获得比常规波束形成更高的阵增益与分辨率。实验数据处理结果验证了四阶累积量波束形成阵增益和分辨率理论结果的一致性。
Abstract:
The fourth-order cumulant of Gaussian distribution zero-mean noise has always been zero theoretically, yet the probability density of real noise and reverberation remains to be a key problem to performance of the fourthorder cumulant beam forming technique. In the present paper, aiming at the instantaneous amplitude distribution of the ambient sea noise and bottom reberberation, we, respectively, deduce the fourth-order cumulant beam forming array gain function; establish the relations between array gain and number of the array elements, ambient sea noise, fourth-order and second-order statistical property of the bottom reverberation as well as input signal-to-noise ratio; also confirm that, compared with conventional beam-forming with critical signal-to-noise ratio and super-critical signal-tointerference ratio, the fourth-order cumulant beam forming could obtain higher gain and better distinguishability than the conventional beam-forming. The results of experiment data processing demonstrate the consistency between theory and consequence of gain and distinguishability of the fourth-order cumulant beam forming.
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