Precise orbit determination for the Jason series of missions and TOPEX/Poseidon in support of a long-term and consistent altimeter record
- (NASA Goddard Space Flight Center)
The precision, stability and quality of the satellite orbit is a critical issue for altimeter missions such as Jason-2 (OSTM) and Jason-3, since the orbits provide the central reference frame within which to analyze and interpret the altimeter data. The long-term (20-25 year) record of altimeter data can now be used alone or in combination with other data sets in studies of intraseasonal-to-interannual variability, global and regional sea level variations, ocean circulation, low-frequency tides, and other phenomena. It is imperative that the orbits used to geolocate the altimeter data be provided with the highest accuracy possible in a consistent reference frame for TOPEX, Jason-1,2, and 3. While we have made significant advances in our ability to model orbits precisely, the significant challenge we face is that we wish to observe the effects of a dynamic Earth with altimeter data but the changes in the Earth itself as manifested in the change in time-variable gravity field of the Earth and the continuing need to update the terrestrial reference frame, influence the quality of the altimeter satellite orbits that we wish to provide. Other challenges arise from the need to minimize or mitigate the effects of modeling errors, in particular those that arise from the nonconservative forces. Our objective will be to minimize or mitigate these errors through choice of modeling or analysis strategy, and prevent these errors from producing unwanted signals in the altimeter data.
For this investigation we propose to: