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Elevation transfer of offshore islands based on GNSS leveling fitting method

In order to solve the problem of lack of elevation datum for offshore unmanned islands, a GNSS level fitting method is proposed to establish the elevation datum of "Dongdanzhi island" and "Sheshan island" of Zhoushan unmanned island. Through the analysis and Research on the special terrain distribution of the survey area, the fitting model is selected as quadratic curve fitting. The experimental results show that the internal coincidence accuracy of GNSS leveling fitting method is within ± 2 mm, and the external coincidence accuracy compared with trigonometric leveling method is ± 4.5 mm. The quality of cross sea elevation transmission is qualified and reliable, which realizes a new method of offshore cross sea elevation transmission and provides a reference for Island elevation fitting.