GRAVITY-FIELD OF THE SOUTHEAST CENTRAL PACIFIC FROM GEOSAT EXACT REPEAT MISSION DATA

Efficient techniques for mapping the marine gravity field with Geosat Exact Repeat Mission (ERM) data are demonstrated. Geosat has completed more than 52 17-day, global ERM repeat cycles and has collected roughly 50 million observations of geoid undulations or, more precisely, sea surface topography. Because the global ground track repeats every 17 days, the ERM observations are highly redundant. By averaging the repeat cycles, very precise profiles of alongtrack geoid undulations are obtained for a region of the southeast central Pacific. The operational Navy Astronautics Group orbits are shown to have systematic errors which may be as large as 10 m. -from Author