RTK (real-time dynamic) carrier phase difference technology is a difference method for real-time processing of carrier phase observation values of two measuring stations. The carrier phase collected by the reference station is sent to the user receiver for difference and coordinate calculation. This is a new commonly used satellite positioning measurement method, which greatly improves the work efficiency.

The elevation value obtained by RTK elevation measurement is calculated under certain assumptions, such as the assumption that the earth is an ideal ellipsoid or that a specific geoid is the horizon. Therefore, the elevation value obtained by RTK elevation measurement is not necessarily 85 elevation or other specific leveling surface elevation.

In addition, the elevation measured by RTK is not necessarily 85 elevation, because the elevation value measured by RTK elevation is calculated under certain assumptions, while 85 elevation is calculated according to specific leveling data, and there are certain differences between them.

Therefore, if more accurate elevation values are needed, more accurate measurement and calculation are needed.