TY - JOUR
T1 - GRACE Follow-On Accelerometer Data Recovery
AU - Behzadpour, Saniya
AU - Mayer-Gürr, Torsten
AU - Krauss, Sandro
N1 - Funding Information:
We would like to thank the German Space Operations Center (GSOC) of the German Aerospace Center (DLR) for providing continuously and nearly 100% of the raw telemetry data of the twin GRACE-FO satellites. Also, we would like to thank the two anonymous reviewers for the detailed comments and the valuable suggestions. Furthermore, we are grateful and acknowledge the JB2008 data courtesy of Space Environment Technologies for providing us the forecasting values for the JB2008 model. This work was funded by the Austrian Research Promotion Agency (FFG) in the frame of the Austrian Space Applications Program Phase 15 (Project 873668), and by The Global Gravity-based Groundwater Product (G3P) project in the framework of the European Union?s Horizon 2020 research and innovative program under Grant Agreement No. 870353.
Funding Information:
We would like to thank the German Space Operations Center (GSOC) of the German Aerospace Center (DLR) for providing continuously and nearly 100% of the raw telemetry data of the twin GRACE‐FO satellites. Also, we would like to thank the two anonymous reviewers for the detailed comments and the valuable suggestions. Furthermore, we are grateful and acknowledge the JB2008 data courtesy of Space Environment Technologies for providing us the forecasting values for the JB2008 model. This work was funded by the Austrian Research Promotion Agency (FFG) in the frame of the Austrian Space Applications Program Phase 15 (Project 873668), and by The Global Gravity‐based Groundwater Product (G3P) project in the framework of the European Union’s Horizon 2020 research and innovative program under Grant Agreement No. 870353.
Publisher Copyright:
© 2021. The Authors.
PY - 2021/5
Y1 - 2021/5
N2 - In Gravity Recovery and Climate Experiment (GRACE) Follow-on (GRACE-FO) mission, similar to its predecessor GRACE, the twin satellites are equipped with three-axis accelerometers, measuring the non-gravitational forces. After 1 month in orbit, during the in-orbit-checkout phase, the noise on GRACE-D accelerometer measurements elevated and resulted in systematical degradation of the data. For this reason, the GRACE-D data need to be replaced by synthetic data, the so-called transplant data, officially generated by the GRACE-FO Science Data System (SDS). The SDS transplant data are derived from the GRACE-C accelerometer measurements, by applying time and attitude corrections. Furthermore, model-based residual accelerations due to thruster firings on GRACE-D were added, proven to improve the data quality in gravity field recovery. However, preliminary studies of GRACE-FO data during the single accelerometer months show that the low degree zonal harmonics, in particular C20 and C30, are sensitive to the current transplant approach. In this work, we present a novel approach to recover the GRACE-D ACT1B data by incorporating non-gravitational force models and analyze its impact on monthly gravity field solutions. The results show the improved ACT1B data not only contributed to a noise reduction but also improved the estimates of the C20 and C30 coefficients. The application of this new approach demonstrates that the offset between Satellite Laser Ranging (SLR) and GRACE-FO derived C30 time series can be reduced by the use of the alternative accelerometer product.
AB - In Gravity Recovery and Climate Experiment (GRACE) Follow-on (GRACE-FO) mission, similar to its predecessor GRACE, the twin satellites are equipped with three-axis accelerometers, measuring the non-gravitational forces. After 1 month in orbit, during the in-orbit-checkout phase, the noise on GRACE-D accelerometer measurements elevated and resulted in systematical degradation of the data. For this reason, the GRACE-D data need to be replaced by synthetic data, the so-called transplant data, officially generated by the GRACE-FO Science Data System (SDS). The SDS transplant data are derived from the GRACE-C accelerometer measurements, by applying time and attitude corrections. Furthermore, model-based residual accelerations due to thruster firings on GRACE-D were added, proven to improve the data quality in gravity field recovery. However, preliminary studies of GRACE-FO data during the single accelerometer months show that the low degree zonal harmonics, in particular C20 and C30, are sensitive to the current transplant approach. In this work, we present a novel approach to recover the GRACE-D ACT1B data by incorporating non-gravitational force models and analyze its impact on monthly gravity field solutions. The results show the improved ACT1B data not only contributed to a noise reduction but also improved the estimates of the C20 and C30 coefficients. The application of this new approach demonstrates that the offset between Satellite Laser Ranging (SLR) and GRACE-FO derived C30 time series can be reduced by the use of the alternative accelerometer product.
KW - Accelerometer
KW - data transplant
KW - GRACE
KW - GRACE-FO
KW - gravity field
UR - http://www.scopus.com/inward/record.url?scp=85105595203&partnerID=8YFLogxK
U2 - 10.1029/2020JB021297
DO - 10.1029/2020JB021297
M3 - Article
AN - SCOPUS:85105595203
SN - 2169-9313
VL - 126
JO - Journal of Geophysical Research: Solid Earth
JF - Journal of Geophysical Research: Solid Earth
IS - 5
M1 - e2020JB021297
ER -