Geodetic SAR for Height System Unification and Sea Level Research—Results in the Baltic Sea Test Network

Coastal sea level is observed at tide gauge stations, which usually also serve as height reference stations for national networks. One of the main issues with using data research that only a few are connected to permanent GNSS needed correct vertical land motion. As new observation technique, absolute positioning by SAR off shelf active radar transponders can be installed instead. year 2020 collected 12 in Baltic Sea area, co-located gauges or stations. From data, 3D coordinates estimated and jointly analyzed records regional geoid estimates. The obtained results promising but exhibit some problems related electronic their performance. At ellipsoidal heights agree range between about 2 50 cm both systems. results, it identified that, most likely, variable systematic instrument delays reason, each transponder needs calibrated individually. Nevertheless, project provides valuable set, offers possibility enhancing methods procedures order develop geodetic technique towards operability.