一种基于CGCS2000框架的单椭球七参数转换法

A senven-parameter model based on single ellipsoid of CGCS2000 frame

针对RTK三维水深测量技术中GPS大地高需拟合成正(常)高的问题,该文在常规七参数转换法的基础上提出一种基于CGCS2000框架的单椭球七参数转换方法,有效弥补了二次曲面法在外推拟合GPS高程时精度衰减的不足。该文重点阐述了单椭球七参数转换法的构造原理、流程及其特点,最后通过椒江出海口水下地形测量项目实例证明:该文算法在拟合精度的内插方面不低于经典的二次曲面法;外推方面,在椒江口向东海外推超过20km时,仍能保证厘米级的拟合精度,且相比二次曲面法精度高出一个数量级。

Aiming at the problem that it is necessary to fit the GPS geodetic height to normal height in RTK 3D water depth measurement technology, this paper proposed a senven-parameter model based on single ellipsoid of CGCS2000 frame according to the senven-parameter, effectively make up for the lack of precision attenuation of the method of quadric surface fitting in the extrapolative fitting of GPS elevation. The principle, process and characteristic of this method were elaborated in this paper. At last this method and the method of quadric surface in fitting the GPS elevation in the underwater topographic survey of Jiaojiang River were compared. The result proved that the method of this paper was super than the method of quadric surface, when the extrapolated range exceeded 20 kilometers, it could still guarantee the precision of centimeter level which was one order of magnitude super than the method of quadric surface.