For this research, the GPS based method will be used. The use of GPS will allow the position of points to be obtained directly and this is good especially when real time method of positioning is involved. In this study, method of RTK-GPS will be applied. Using RTK technique, final depth measurement can be calculated directly. This is because the tidal value already adds up in depth taken from echo sounder to seabed and height of GPS when using software such as HYDROpro.
Article title: " HYDROGRAPHIC SURVEY USING REAL TIME KINEMATIC METHOD FOR RIVER DEEPENING"
In bathymetric survey, it is a combination between GPS-RTK coordinates for a such reference datum in the measurement ship and connected to an Echo sounder to estimate the depth of the water related to the same datum. then you get a sheet of coordinates with bed levels.