Gravity Field Solution by Exploiting the Full Potential of GRACE Follow-On

Kurzfassung

The GRACE-FO mission, featuring the advanced Laser Ranging Interferometer (LRI), provides inter-satellite range measurements with an unprecedented level of precision—estimated to be 5 to 50 times higher than those achieved by the original GRACE mission. As demonstrated in previous studies, the LRI’s precision no longer limits gravity field recovery. Instead, other factors such as deficiencies in background models and incomplete instrument calibration have become the primary constraints on solution quality. To fully exploit the capabilities of the LRI system, this project advances alternative modeling strategies for gravity field estimation, with a particular focus on the Extended Acceleration Approach (EAA). The EAA augments the conventional low-low satellite-to-satellite tracking (LLSST) framework by adding two condition equations that incorporate dynamic information from directions beyond the along-track component. This multidirectional formulation allows for a more complete representation of satellite motion and gravitational signal sensitivity. Simulation results show that the implementation of the EAA reduces striping artifacts commonly seen in monthly gravity solutions and enhances the spatial resolution of the recovered fields. These improvements underscore the potential of the EAA to become an integral part of future gravimetry missions and highlight the value of rethinking observation models to match the performance of next-generation instruments like the LRI.