A mobile absolute gravimeter based on atom interferometry for highly accurate point observations

这项工作的主要重点是为地球物理学界提供一种新型的绝对重力仪，这种仪器已经在现场测量中证明了它的功能，并且至少比传统的现场重力仪的精度高出一个数量级。便携式量子重力仪GAIN（“重力原子干涉仪”）是在Humboldt-Universität柏林大学（HU）开发的，现在是HU的仪器开发人员和汉诺威研究所（IfE）的绝对重力仪小组合作的主题。该仪器的进一步开发旨在将GAIN应用于地球物理研究领域。典型的任务是研究地下物质运动（例如在构造活跃地区），区分陆地水圈中的人为和自然环境影响，或诸如监测地下水库等技术应用。主要的挑战是对系统效应的理解和控制，以及传感器的便携性和长期稳定性的提高。为了识别和克服GAIN系统仍然固有的系统影响，使用经典的最先进的相对重力仪和绝对重力仪（包括IfE的FG5-220）进行直接比较。这对于考虑重力值的持续变化是必要的，而重力值的持续变化主要是由于潮汐、大气变化和水文变化。我们计划分三个步骤演示完成的仪器的功能、灵敏度和准确性：(A)在最初两年的开发阶段同时进行比较：原子仪器与经典仪器；(B)抽水蓄水池的精密实验；(C)在需要绝对精度的Fennoscandian陆地隆升区使用GAIN和FG5-220的地球物理项目。

The main focus of this work is to provide the geophysical community with a novel type of absolute gravimeter that will have already proven its functionality at on-site measurements and surpasses the precision of conventional field gravimeters by at least one order of magnitude.The portable quantum gravimeter GAIN (“Gravimetric Atom Interferometer”) has been developed at the Humboldt-Universität zu Berlin (HU) and is now subject of a cooperation between the instrument developers at HU and the absolute gravimetry group at the Institute für Erdmessung in Hannover (IfE). Further development of the instrument aims at the application of GAIN in the research field of geophysics. Typical tasks are to study subterranean mass movements (e.g. in tectonically active regions), to discriminate between man-made and natural environmental effects in land hydrosphere, or technical applications such as the monitoring of underground water reservoirs.The main challenges are the understanding and control of systematic effects as well as the improvement of the sensor’s portability and long-term stability. To identify and overcome systematic effects still inherent in the GAIN system, classical state-of-the-art relative and absolute gravimeters (including the IfE’s FG5-220) are used for direct comparisons. This is necessary to account for the continuously varying gravity value, which is mainly due to tides, atmospheric changes and hydrological variations.We plan to demonstrate the functionality, sensitivity and accuracy of the completed instrument in three steps: (A) simultaneous comparisons during the initial two-year development phase: atomic versus classical instrument; (B) a precision experiment in a pumped-storage water reservoir; (C) a geophysical project with GAIN and FG5-220 in the Fennoscandian land uplift area where absolute accuracy is needed.