Cold Atom Interferometry Accelerometers for Future Satellite Gravity Missions

Kurzfassung

Satellite gravity missions like GOCE, GRACE and GRACE-FO successfully recovered the global Earth's gravity field and thus reveal valuable insights for geosciences and other disciplines. The accelerometers onboard of these satellite missions are one of the limiting factors and consequently the new concept of Cold Atom Interferometry (CAI) is studied for improved future satellite gravity missions. The simulated measurements of classical electrostatic and CAI accelerometers are combined by a Kalman filter in order to benefit from their complementary characteristics in sampling rate and long-term stability. The effect on the recovered gravity field solution is evaluated by closed-loop simulations for low-low Satellite-to-Satellite Tracking (ll-SST) and satellite gravity gradiometry. Additionally, a combination of these two measurement concepts, i.e. one satellite of an ll-SST mission is equipped with a cross-track gradiometer, is presented. The simulation results show the benefit of an additional CAI accelerometer, but also reveal critical factors as the time-variable background modelling, the rotation-induced phase shift and the required accuracy for the angular velocity determination. The concepts are examined for different orbital altitudes and constellations.