利用海底反射信号进行地声参数反演的方法

针对现有反演方法的缺点，提出了一种基于海底反射信号的地声参数高分辨反演方法.它利用短距离声源在不同深度上发射宽带线性调频信号，采用垂直阵进行接收，首先通过匹配滤波方法提取多径到达信息，然后利用海底反射损失曲线，反演海底表层的声速和密度，最后利用浅底层反射信号估计沉积层参数.由于海水中直达波受到内波的强烈影响，选择海底表面反射作为参考，用以可靠地计算浅底层反射的相对到达时间和幅度，从而估计出沉积层的厚度、速度和衰减系数.通过海上实验，验证了利用浅底层反射信号反演参数的有效性. 关键词： 海底参数 反演 浅底层反射信号

A geoacoustic inversion method based on bottom reflection signals

It is important for underwater acoustic modeling and passive localization to estimate the geoacoustic properties with high accuracy. A geoacoustic inversion scheme was presented, which uses a broadband source to generate the linear frequency-modulated signal at different ranges and depth. The signal was received by a vertical array. The bottom reflection loss was extracted by matched filtering and then used to estimate the sea-bottom density and sound speed. Meanwhile, an inversion method based on sub-bottom reflection was investigated using the experimental data. Because the direct arrivals in the water were influenced strongly by the internal waves, the first sea-bottom reflection was taken as the reference path to calculate the relative arrival time and amplitude of sub-bottom reflections. Firstly the sediment sound speed and thickness were estimated using different source depth and receiver depth. Then the sediment attenuation was estimated by assuming that it has linear frequency dependence. The estimated values of the sediment properties compared well with the core data, chirp sonar data, and the matched field inversion results.