In-field Sound Speed Profile (SSP) measurement is still indispensable for achieving centimeter-level-precision Global Navigation Satellite System (GNSS)-Acoustic (GNSS-A) positioning in current state of the art. However, in-field SSP measurement on the one hand causes a huge cost and on the other hand prevents GNSS-A from global seafloor geodesy especially for real-time applications. We propose an Empirical Sound Speed Profile (ESSP) model with three unknown temperature parameters jointly estimated with the seafloor geodetic station coordinates, which is called the 1st-level optimization. Furthermore, regarding the sound speed variations of ESSP we propose a so-called 2nd-level optimization to achieve the centimeter-level-precision positioning for monitoring the seafloor tectonic movement. Long-term seafloor geodetic data analysis shows that, the proposed two-level optimization approach can achieve almost the same positioning result with that based on the in-field SSP. The influence of substituting the in-field SSP with ESSP on the horizontal coordinates is less than 3 mm, while that on the vertical coordinate is only 2–3 cm in the standard deviation sense.

中文翻译：

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具有自构造经验声速廓线的厘米级精度海底大地测量定位模型

在当前技术水平下，现场声速剖面（SSP）测量对于实现厘米级精度的全球导航卫星系统（GNSS）声学（GNSS-A）定位仍然是不可或缺的。然而，现场SSP测量一方面导致巨大的成本，另一方面阻碍GNSS-A进行全球海底大地测量，特别是对于实时应用。我们提出了一种经验声速剖面（ESSP）模型，其中三个未知温度参数与海底大地测量站坐标联合估计，称为第一级优化。此外，针对ESSP的声速变化，我们提出了所谓的二级优化，以实现厘米级精度的定位来监测海底构造运动。长期海底大地测量数据分析表明，所提出的两级优化方法可以达到与现场SSP几乎相同的定位结果。用ESSP代替现场SSP对水平坐标的影响小于3毫米，而对垂直坐标的影响在标准偏差意义上仅为2-3厘米。