超低频天线设计中的运动感应噪声研究

为进一步改善超低频天线收信性能，建立了磁场天线的理想振动模型，分析了天线灵敏度设计对运动感应噪声的影响，详细推导了均匀灵敏度天线的运动感应噪声功率谱，并在相同条件下与抛物线型灵敏度天线作对比，对比结果表明，2种天线在不同频率和天线长度下诱发的噪声强度不同，但均匀灵敏度型天线诱发的噪声始终要多于抛物线型灵敏度天线。通过优化配置线圈的电磁结构，给出了实际天线灵敏度的设计方法。针对运动感应噪声功率谱影响较大的横向力分布谱密度，通过多项式拟合和指数拟合的方式设计了新的表达式，利用该表达式进行仿真实验，并在不同天线长度和潜艇航速下，与目前主流的横向力分布谱密度函数进行对比分析。仿真结果表明，数据拟合得到的运动感应噪声谱密度随着天线长度的增加而降低，随着潜艇航速的加快而增大；指数拟合方式诱发的运动感应噪声强度与主流表达式诱发的强度基本一致，多项式拟合方式诱发的运动感应噪声相对较低。

Research on motion-induced noise in the design of ultra low frequency antenna

To improve the receiving performance of the ULF antenna, the ideal lateral vibration model of H-field antenna is established, the influence of antenna sensitivity design on motion-induced noise is analyzed, and the power spectrum of the motion-induced noise with uniform-sensitivity antenna is deduced in detail and compared with parabolic-sensitivity antenna under the same condition. The comparison shows that the above antennas induce different noise intensity at different frequency and antenna length, but the former is always more than the latter. By optimizing the electromagnetic structure of the coil, the fact design method of antenna sensitivity profile is given. In terms of cross-spectral density of force which has great influence on power spectral density of motion-induced noise, the new expression is designed by means of polynomial fitting and exponential fitting. The simulation experiment is carried out compared with the current mainstream expression by using this expression under different antenna length and submarine speed. The simulation shows that spectral density of the motion-induced noise obtained by the proposed expression decreases with the increase of the antenna length and increases with the speed of the submarine; the intensity of the motion-induced noise by exponential fitting is basically consistent with the mainstream expression, and the intensity by polynomial fitting is relatively low.