| In multibeam bathymetry, the vertical datum is variable and instantaneous, influenced by tides. In traditional multibeam bathymetry, we should set up one or more tide stations in the survey area, to synchronously observe the water level, and reduce the water depth to the chart datum. Due to the complexity of vertical datum conversion in multibeam bathymetry, we propose a vertical datum conversion model for multibeam non-tidal sounding, by building the quasi-geoid model with interpolation method in the survey area, with the EGM and the GNSS/leveling data. This method can directly obtain the bathymetric value of depth datum and meet the demand of offshore multibeam bathymetry. In terms of error, this method can effectively eliminate the effects of tides, dynamic draft, surging waves or other factors, which improve work efficiency. |
