EGSIEM: scientific combination service for monthly gravity fields
July 6, 2017 • 145 Views
Workshop 2017 - Ulrich Meyer - Motivated by and based on the experiences of the IGS, the European Gravity Service for Improved Emergency Management (EGSIEM) project offers a scientific combination service, combining monthly GRACE gravity fields of associated analysis centers (ACs). The combination is performed on normal equation (NEQ) level, thus taking all correlations between the gravity field coefficients and pre-eliminated orbit and instrument parameters correctly into account. Consistency between individual contributions is guaranteed by a set of common processing standards, but the noise models applied by the different ACs are very diverse. Neither the resulting formal errors nor a posteriori variance factors represent the true solution noise of the monthly gravity fields that is still governed by analysis noise.