The satellite-only gravity field model GOCO2025s

GOCO2025s is a satellite-only, global gravity field model up to degree and order 300, with constrained secular, annual, and semi-annualvariations up to degree and order 200.

GOCO2025s is the latest release in the Gravity Observation Combination (GOCO) series—an initiative aimed at computing high-accuracy and high-resolution static global gravity field models (www.goco.eu). The model is based on satellite data collected between 2002 and 2024 (inclusive). Contributing satellite missions include GOCE (TIM6 gradiometer observations), GRACE and GRACE-FO (KBR and LRI observations), as well as kinematic orbits from CHAMP, GOCE, Swarm A/B/C, Sentinel-1A/1B/2A/2B/3A/3B/6A, TerraSAR-X, TanDEM-X, and satellite laser ranging observations (ITRF2020 reference frame) to AJISAI, BLITS, LAGEOS-1, LAGEOS-2, LARES, LARES-2, LARETS, Starlette and Stella. The temporal variations include observations up to degree and order 150 and are regularized using isotropic noise, separated by land/ocean masks up to degree and order 200. The combination of individual data sources is based on the full system of normal equations, with relative weighting among the constituents determined via variance component estimation.

The individual files of GOCO2025s contain:

"GOCO2025s.gfc":

Static and time-dependent gravity field coefficients in terms of spherical harmonics and their respective uncertainty information.An algorithm on how to compute a gravity field functional at a specific time can be found in the header. 

"GOCO2025s_normalEquation.snx":          

All parts of the normal equation system of the static gravity field, including the original normal equation, the vector of the right hand side, apriori values of the unknown parameters, the normal equation of the applied constraints and the resulting solution vector.

"AOD1B_RL0X_included_in_GOCO2025s.gfc":  

The gravitational potential of non-tidal atmospheric and ocean masses already included in GOCO2025s.In order to use GOCO2025s together with AOD1B RLO6 or RL07, the respective files have to reduced beforehand.