Page - 28 - in Contributions to GRACE Gravity Field Recovery - Improvements in Dynamic Orbit Integration, Stochastic Modelling of the Antenna Offset Correction, and Co-Estimation of Satellite Orientations

4.4 Data Flow GRACE data is processed in several steps, or levels, before being made available to the science community. This processing occurs under the framework of the SDS, the GRACE Science Data System. Level 0 data contains raw decommutated telemetry that has been downloaded from the satellites by the GRACE Raw Data Center at DLR in Neustrelitz. This data is transformed to engineering units by applying sensor calibration factors to yield level 1A data. It is then referenced into the SRF, time-tagged, filtered, and down-sampled, which results in level 1B data. Level 1A and level 1B data are generated by JPL and GFZ. This is the data source that is available to the general science community, and on which the results in this thesis are based. The gravity field solutions computed from level 1B data are level 2 products. Data products derived from level 2 products, such as mass anomaly grids, are level 3 products. Chapter4 The GRACE Satellites28