Quantum optical technology provides an opportunity to develop new kinds of gravity sensors and to enable novel measurement concepts for gravimetry. Two candidates are considered in this study: the cold atom interferometry (CAI) gradiometer and optical clocks. Both sensors show a high sensitivity and long-term stability. They are assumed on board of a low-orbit satellite like gravity field and steady-state ocean circulation explorer (GOCE) and gravity recovery and climate experiment (GRACE) to determine the Earth’s gravity field. Their individual contributions were assessed through closed-loop simulations which rigorously mapped the sensors’ sensitivities to the gravity field coefficients. Clocks, which can directly obtain the gravity potential (differences) through frequency comparison, show a high sensitivity to the very long-wavelength gravity field. In the GRACE orbit, clocks with an uncertainty level of 1.0×10-18\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1.0\times 10^{-18}$$\end{document} are capable to retrieve temporal gravity signals below degree 12, while 1.0×10-17\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1.0\times 10^{-17}$$\end{document} clocks are useful for detecting the signals of degree 2 only. However, it poses challenges for clocks to achieve such uncertainties in a short time. In space, the CAI gradiometer is expected to have its ultimate sensitivity and a remarkable stability over a long time (measurements are precise down to very low frequencies). The three diagonal gravity gradients can properly be measured by CAI gradiometry with a same noise level of 5.0 mE/Hz\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm{mE}/\sqrt{\mathrm{Hz}}}$$\end{document}. They can potentially lead to a 2–5 times better solution of the static gravity field than that of GOCE above degree and order 50, where the GOCE solution is mainly dominated by the gradient measurements. In the lower degree part, benefits from CAI gradiometry are still visible, but there, solutions from GRACE-like missions are superior.

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使用量子光学传感器从太空确定地球重力场

量子光学技术为开发新型重力传感器和实现新的重力测量概念提供了机会。本研究考虑了两个候选者：冷原子干涉仪 (CAI) 梯度仪和光学钟。两种传感器都显示出高灵敏度和长期稳定性。假设它们安装在低轨道卫星上，如重力场和稳态海洋环流探测器 (GOCE) 以及重力恢复和气候实验 (GRACE)，以确定地球的重力场。他们的个人贡献是通过闭环模拟来评估的，该模拟将传感器的灵敏度严格映射到重力场系数。时钟，可以通过频率比较直接获得重力势（差），对超长波长重力场表现出高灵敏度。在 GRACE 轨道上，时钟不确定度为 1.0×10-18\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \ usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1.0\times 10^{-18}$$\end{document} 能够检索度以下的时间重力信号12, 而 1.0×10-17\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek } \setlength{\oddsidemargin}{-69pt} \begin{document}$$1.0\times 10^{-17}$$\end{document} 时钟仅用于检测 2 级信号。然而，它对时钟在短时间内实现这种不确定性提出了挑战。在太空中，CAI 梯度计有望在很长一段时间内具有极高的灵敏度和卓越的稳定性（测量精确到非常低的频率）。三个对角线重力梯度可以通过 CAI 梯度测量正确测量，噪声水平为 5.0 mE/Hz\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm{mE}/\sqrt{\mathrm{Hz}}}$ $\end{文档}。它们可能会导致静态重力场的解决方案比 GOCE 50 级以上的解决方案好 2-5 倍，其中 GOCE 解决方案主要由梯度测量主导。