Hybrid architectures with quantum gravity gradiometry and satellite-to-satellite tracking for spaceborne mass change measurements - A sensitivity and performance analysis

Advances in atom interferometry have led to quantum gravity gradiometer instruments, which have further led to spaceborne mission concepts utilizing this technology to measure Earth's gravity field and its time variations. The mass changes inferred from gravity change measurements lead to greater understanding of the dynamical Earth system, as demonstrated by GRACE and GRACE Follow-On missions.

We report the results from a sensitivity and performance assessment study with quantum gradiometers used in two configurations - first as a single-axis gradiometer with a GNSS receiver; and second in a novel hybrid configuration combining cross-track quantum gravity gradiometer and an inter-satellite tracking system. The relative advantages of the two configurations are assessed in terms of their susceptibility to system errors (such as tracking, pointing, or measurement errors), and to modeling errors due to aliasing from rapid time-variations of gravity (so-called "de-aliasing errors"). We conclude with a specification of the key measurement error thresholds for a notional hybrid gravity field mapping mission.