Cold Atom Interferometry Accelerometry for Future Low-Low Satellite-to-Satellite Tracking and Cross-track Gradiometry Satellite Gravity Missions

Abstract

Satellite gravity missions give unprecedented insights in the Earth system. However, a further improvement in spatial and temporal resolution is required to better monitor the various geo-processes. When considering the sensors of satellite missions, the accelerometers are the limiting factors. Cold Atom Interferometry (CAI) accelerometers are characterized by their long-term stability and an accurate knowledge of the scale factor. Closed-loop simulations are performed in order to quantify the influence of different accelerometer performances on the gravity field recovery. The impact of the scale factor knowledge on the acceleration measurement is evaluated in terms of a requirement based on the non-gravitational acceleration signal and the accelerometer noise. Furthermore, the variation of the non-gravitational acceleration signal within one interferometer cycle is studied. It is demonstrated that both aspects are significant. The impact on the acceleration measurements can be reduced to an acceptable level by drag compensation. Moreover, the addition of a CAI cross-track gradiometer to a low-low Satellite-to-Satellite Tracking mission is investigated, as supplemental observations in east-west direction are provided. This combination enhances the estimation of the high-degree coefficients and reduces the striping effects in north-south direction. We acknowledge the support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Project-ID 434617780 - SFB 1464 and under Germany's Excellence Strategy - EXC-2123 Quantum-Frontiers - 390837967 and the support by Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) for the projects Q-BAGS and QUANTGRAV.