The CDDIS was established in 1982 as a dedicated data bank to archive and distribute space geodesy related data sets. Today, the CDDIS archives and distributes mainly Global Navigation Satellite Systems (GNSS, currently Global Positioning System GPS and GLObal NAvigation Satellite System GLONASS), laser ranging (both to artificial satellites, SLR, and lunar, LLR), Very Long Baseline Interferometry (VLBI), and Doppler Orbitography and Radio-positioning Integrated by Satellite (DORIS) data for an ever increasing user community of geophysists.
GEODYN is used extensively for satellite orbit determination, geodetic parameter estimation, tracking instrument calibration, satellite orbit prediction, as well as for many other items relating to applied research in satellite geodesy using virtually all types of satellite tracking data.
The GSFC time variable gravity mascon products optimize the signal-to-noise ratio through the application of spatial regularization in the estimation of both monthly and high-resolution trends from GRACE and GRACE-FO Level 1B data. These mascon products do not require any additional filtering prior to their research application.
The Earth as a whole responses to external forces as an elastic body. Putting additional mass on the Earth's surface causes crust deformation. Changes of loading mass result in variable displacements of Earth's surface.
A series of global ocean tide models has been developed in this laboratory, primarily from analysis of satellite altimetry. Some of the models are widely used in space geodetic applications. Some are available here; other iterations are available by inquiry.
Satellite laser ranging (SLR) tracking data provides more than four decades of measurements useful for estimating the long wavelength components of time-variable gravity, including C20 and C30. The estimation of these gravity coefficients with SLR has been critical to the success of the GRACE and GRACE-FO missions. GSFC routinely provides estimates of the gravity coefficients up to degree and order 5.
