Accelerometer data transplant for future satellite gravimetry

Accurate monitoring of the Earth's gravity field is crucial for understanding mass redistribution processes related to climate change, hydrology, and geodynamics. The Gravity Recovery and Climate Experiment (GRACE) and its successor, GRACE Follow-On (GRACE-FO), have provided invaluable satellite gravimetry data through low-low satellite-to-satellite tracking (LL-SST). However, the precision of gravity field recovery is significantly affected not only by data gaps in the accelerometer (ACC) measurements, but also by potential failures or limitations in their performance. To mitigate these issues, accelerometer data transplantation has been employed, leveraging the similarity in non-gravitational accelerations experienced by both satellites. This study presents an in-depth assessment of transplant noise and evaluates advanced accelerometer configurations, including Cold Atom Interferometry (CAI) accelerometers and hybrid electrostatic-quantum accelerometer setups for future satellite gravimetry missions. Through closed-loop LL-SST simulations, we compare four different accelerometer configurations, ranging from conventional electrostatic accelerometers (EAs) to fully hybrid CAI-EA setups. Results indicate that a dual hybrid accelerometer configuration offers the highest accuracy in gravity field recovery, while a transplant-based hybrid approach significantly enhances the performance of non-gravitational force modeling without requiring additional instrumentation. The findings underscore the potential of quantum accelerometery and transplant methodologies for future satellite gravimetry missions, offering a cost-effective solution to improve gravity field recovery, while benefitting from new sensor types.