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基阵的信噪比增益与噪声场空间特性密切联系, 海洋环境噪声空间特性建模始终是水声学研究的热门问题. 声纳功能不同, 其工作频段和带宽通常也不相同, 因此, 任意频带噪声场的空间相关系数对声纳系统设计具有重要参考价值. 依据海洋环境噪声场的产生过程, 在高频近似条件下, 本文提出一种噪声场时域建模方法, 给出了水平分层介质中表面噪声时域声压和质点振速的积分表示, 为噪声矢量场宽带模型的建立奠定了基础. 根据风成噪声谱结构, 数值计算了不同频带、不同谱斜率的噪声场空间相关系数, 揭示了带宽、谱结构对风成噪声空间特性的影响规律. 随着阵元间距和带宽增大, 噪声矢量场各分量的空间相关系数的振荡周期数逐渐减少, 振荡幅度逐渐减小, 这是由于噪声场相关系数频域平均的结果. 当谱斜率小于零时, 宽频带噪声场的空间相关半径大于窄带噪声场的相关半径, 这是由于低频段噪声起主要贡献的结果, 实测海洋环境噪声声压场竖直方向空间相关特性变化规律与理论结果一致. 本文模型对换能器成阵技术研究以及环境参数反演具有潜在应用前景.The signal-to-noise ratio gain of the array is closely related to the spatial characteristics of the noise field. The modeling of the spatial characteristics of marine environmental noise is always a hot spot. For sonar with different functions, the working frequency band and bandwidth are usually different. Therefore, the spatial correlation coefficient of the noise field in arbitrary frequency band has important reference value for designing sonar systems. According to the process of generating the marine environmental noise field under the high frequency approximation condition, a noise field time-domain modeling method is proposed, and the integral expression of the time-domain sound pressure and particle vibration velocity of marine environmental noise in a horizontally layered medium is given. This lays the foundation for establishing a broadband model of the noise vector field. In particular, the analytical expression of the spatial correlation coefficient of the broadband white noise vector field in the vertical direction under specific condition is also given. Following the spectral structure of wind-generated noise, the spatial correlation coefficients of noise fields with different frequency bands and different spectral slopes are numerically calculated, revealing the influence of bandwidth and spectral structure on the spatial characteristics of marine environmental noise, and the principle behind the result is explained through theoretical derivation. With the increase of the array element spacing and bandwidth, the number of oscillation periods and the oscillation amplitude of the spatial correlation coefficient of each component of the noise vector field gradually decrease, which is caused by the frequency domain average of the noise field correlation coefficient. When the spectral slope is less than zero, the low-frequency noise plays a major role, causing the spatial correlation radius of the broadband noise field to be larger than that of the narrowband noise field. The result of the experiment conducted in South China Sea shows that the measured vertical spatial correlation coefficient of the sound pressure field of marine environmental noise is in good agreement with the theoretical result. The model has potential application prospects for the research of transducer array technology and the inversion of environmental parameters.
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