Application of satellite altimeter data to orbit error correction and gravity model adjustment

Abstract

The full exploitation of the oceanographical information contained in altimeter height observations made during altimetry missions of the past (SEASAT), present (GEOSAT) and future (ERS-1, TOPEX/Poseidon), requires very accurate satellite orbits. Although the dynamic models involved in the orbit computation are of steadily increasing accuracy, the strived-for accuracy of 10 cm of the radial position component may not be achieved for all these missions in the near future.Several techniques have been devised to apply altimeter or cross-over data to satellite orbit correction and gravity model adjustment. This paper will address two methods which are currently being developed at Deift University of Technology (DUT). Using analytical theory, a gravity model may be adjusted with a limited number of laser range and cross-over difference observations by applying constraint matrices. This technique was successfully applied to tune the GEM-Ti model. With the same theory a new method of orbit error correction used by the so-called cross-over minimization technique for restricted areas has been devised, which allows the recovery of the eliminated orbit error, and the combination of these errors from several areas into a global error model.

The role of orbit errors in processing of satellite altimeter data

“…Function (6.11) is found by linearization of a Kepler ellipse as described by equation (4.24). Its physical justification is discussed by Colombo (1984b), Rummel (1985), Wagner (1985) and Zandbergen et al (1988). Function (6.12) is found by solving the special resonant case of the Hill equations, as is shown by equation (4.39).…”