Sentinel POD based on DORIS, GPS and SLR and subsequent reference frame determination based on DORIS-only

The absolute positional accuracy of altimetry satellites is one key aspect for subsequent analyses in Earth observation. To determine the position of a satellite with highest accuracy, various observation techniques are obtainable. Recent satellites like the Copernicus Sentinel-3A/3B and 6A Michael Freilich (MF) satellites are equipped with multiple observation techniques onboard. We use the techniques Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS), Global Positioning System (GPS) and Satellite Laser Ranging (SLR) to generate orbits based on DORIS-only, on the combination of DORIS and SLR, and on GPS-only. To examine the accuracy of the orbits, we compare them inter-technique-wise and with an external combined orbit solution, which is assumed to have superior absolute accuracy and minimal residual systematic errors. Subsequently, we strive to generate reference frame realizations for the DORIS technique in order to be able to contribute an additional solution to the International DORIS Service (IDS) in the future. Therefore, we use the DORIS only-orbit solutions, and generate weekly local reference frames for each of the three satellites and in combination. We evaluate these based on the reference frame defining parameters, i.e. origin, scale and orientation.