In addition to the tide gauges, sea level research nowadays is based on a number of measurement systems, which all have their own characteristics and deliver different type of observations. In order to analyze all observations they need to be available in a common reference frame.

The goals of the project are: (1) Connecting the tide gauge markers with the GNSS network geometrically in order to determine the relative vertical motion and to correct the tide gauge readings. Geodetic SAR (Sentinel 1) is used for connecting tide gauges to the GNSS network. (2) Determine a GOCE based high resolution geoid at tide gauge stations in order to deliver absolute heights of tide gauges with respect to a global equipotential surface as reference. (3) Joint analysis of geometrical and physical reference frames to make them compatible, and to determine corrections to be applied for combined analysis of geometric and physical heights.