长江口外远距离海上平台垂直基准体系的建立

Establishing of vertical datum system for offshore platform outside Yangtze River Estuary

为了解决复杂水文条件和远距离等因素给垂直基准传递带来的精度低、可靠性无法验证的难题,提出并研究了长江口外远距离海上平台垂直基准体系的建立方法。首先,建立了覆盖平台水域的GNSS控制网;然后,给出了联合似大地水准面精化模型、平均海平面及海面地形的1985国家高程计算方法、平均海平面和深度基准面综合确定方法;最后,形成了平台垂直基准远距离传递的完整方案。借助于上述方法开展了长江口外远距离海上平台垂直基准传递研究,获得了互差为2 mm的平台1985国家高程以及精度优于3 cm和5 cm的平台平均海平面和深度基准面,在此基础上,建立了长江口外远距离海上平台的垂直基准体系。

For solving the low accuracy and low reliability of vertical datum transmission caused by complex hydrological conditions and long distance, this paper proposed a method of establishing vertical datum for long-distance offshore platforms outside the Yangtze River Estuary.Firstly, the GNSS control network was established in the water area.Subsequently, combined with the quasi-geoid refinement model, the mean sea level and sea surface topography, a method for determining 1985 national elevation was given, based on which the comprehensive method for determining the mean sea level and chart datum was given.Finally, a completed scheme for the long-distance transmission of vertical datum was formed.To verify the validity of the proposed method, this paper had determined the vertical datum of the offshore platform by the proposed method.The results showed that the mutual difference of determining the 1985 national elevation was 2 mm and the standard deviations of determining the mean sea level and the depth datum L of the platform were 3 cm and 5 cm respectively.