海洋声学环境下水中声源的时延估计法定位精度分析

水中声源的定位精度受到海洋声学环境的重要影响。结合海上试验的实际应用,分析了水下观测平台采用时延估计法对声源的定位精度问题。根据理论分析,计算了时延估计误差、海洋中声速不均匀、平台非稳性、及声传播起伏等因素引起的俯仰角和方位角误差。利用误差传递公式,获得了上述因素引起的不同平台深度下,不同距离声源的定位误差。比较了采用平面阵与立体阵、是否补偿声线弯曲效应等条件下定位误差的变化,并通过海上试验结果进行了部分验证。研究结果表明,海洋声速不均匀对定位误差的贡献最大。采用立体阵代替平面阵、测量海洋声速剖面并补偿声线弯曲引起的定位误差,在1000m距离上可使定位相对误差从最大30%降低到约10%,有效提高了较远距离上的定位精度。研究结果对于采取措施提高水中声源的定位精度有指导意义。 

Precision analysis for underwater sound source localization in ocean acoustic environment with time delay estimation method

The localization precision of underwater sound source is influenced significantly by the ocean acoustic environment. Aiming at the engineering applications at sea, we analyze the problem of localization precision on an underwater platform with time delay estimation method. We first compute the estimation errors of the pitch and azimuth angle introduced by such factors as the time delay estimation error, the inhomogeneous ocean media, the instability of the platform, and the fluctuation of sound transmission based on theoretical analysis. Then we obtain the localization error with varying depth of platform and varying range of sound source by using the error transmission formula. We also compare the localization error of a planar array with a 3-demensional array, and in conditions of compensating the sound ray reflection effect or not. The results are partially verified with the data recorded in sea trials, which show that the inhomogeneous ocean media contributes most to the total localization errors. When employing a 3-demensional array instead of a planar array, and measuring the ocean sound speed profile to compensate the sound ray refraction, the relative localization error would reduce from the maximum of 30% to 10%. The above results give a guidance for taking effective measures to improve the localization precision of the underwater sound source.