Within the marine geodetic research center at the Technical University Hannover there is one project that deals with methods for precise marine positioning, including satellite Doppler techniques. In 1977 a Doppler measuring campaign of eight weeks was performed for the precise positioning of the German research rig FPN in the North Sea. The results of this campaign, including an antenna height variation study and the comparison with trans‐horizon electromagnetic distance measurements over sea, are presented and discussed. Height differences turn out to be reproduced by the Doppler solution within a few decimeters, and distance differences remain below 1 m. During the summer of 1978 a first experiment with Doppler positioning of a buoy near the research rig was carried out. Experiences and preliminary results of this experiment are presented.