Benefit of Cold Atom Interferometry Inertial Sensors for Future Satellite Gravity Missions

Satellite gravity missions are a powerful tool to measure the global Earth’s gravity field and consequently provide important information for geosciences. However, improvements in spatial and temporal resolution are required for many applications. Simulation studies are performed to quantify the influence of improved sensors, orbit parameters and measurement concepts on the recovered gravity field solution. The investigations focus primarily on accelerometers by evaluating the concept of Cold Atom Interferometry (CAI) accelerometers and their combination with electrostatic accelerometers for future satellite gravity missions. CAI accelerometers with their long-term stability would complement the classical electrostatic accelerometers very well.

Different accelerometer performance levels and orbit designs are tested within a closed-loop simulation in order to quantify their impact on the gravity field solution. The modelling of the CAI behavior accounts for several noise sources and systematics such as the detection noise, laser frequency noise, wavefront aberration, and sources of contrast loss. The effects of satellite rotations and their compensation by a counter-rotation mirror are also considered. Furthermore, the benefit of a quantum gyroscope is investigated. The measurement of the rotation rate is a critical factor for the required rotation compensation and also in gradiometry scenarios.

Additionally, simulation results for the pathfinder mission Cold Atom Rubidium Interferometer in Orbit for Quantum Accelerometer (CARIOQA) are presented. CARIOQA will demonstrate the application of a CAI as an accelerometer in space. As preparation of the pathfinder mission, closed-loop simulations for gravity field recovery are performed for two scenarios: 1) The CARIOQA pathfinder mission involves a single satellite utilizing high-low satellite-to-satellite tracking. 2) A possible future quantum space gravimetry mission consists of a constellation of multiple satellites operating in a low-low satellite-to-satellite tracking mode.

We acknowledge the support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy – EXC-2123 Quantum-Frontiers – 390837967 and the European Union for the project CARIOQA-PMP (Project-ID 101081775). This work is also supported by the Federal Ministry for Economic Affairs and Climate Action (BMWK), Project 50NA2310A (SpaceQNav).