Terms of Reference
President: Jürgen Müller (Germany)
Vice President: Marcelo Santos (Canada)
QuGe website - www.quge.iag-aig.org
Terms of Reference
The advancements in quantum physics over the past decade have ushered in a new era of possibilities, particularly in satellite geodesy and terrestrial gravity sensing. The IAG Project Novel Sensors and Quantum Technology for Geodesy (QuGe) harnesses these breakthroughs alongside innovative measurement concepts. It is a collaborative project between physics and geodesy, which aims to leverage quantum technology’s potential for a myriad of groundbreaking applications in geodesy. Changes in the Earthsystem manifest in mass variations, spanning the hydrosphere, geosphere, and atmosphere. These changes are intricately linked to gravitational data, necessitating higher resolution and accuracy, the highest are achievable only through quantum technology. Stable reference systems, crucial for monitoring Earth’s dynamic processes, rely heavily on precise timekeeping, marking clocks as pivotal components in future endeavors. The QuGe project stands as a unique platform for developing and testing novel concepts and observation systems, with potential applications extending to exploration and navigation. Synergies of technology development with geodetic and geophysical modeling are imperative. Optical ranging, atom-interferometric accelerometry, and chronometric levelling are proposed methods to overcome limitations in traditional geodesy [1]. These innovative techniques promise unparalleled accuracy in observing mass variations across various spatial and temporal scales, thus, facilitating applications ranging from groundwater basin monitoring to understanding global mass transport in oceans. QuGe, with its fusion of quantum physics and geodesy expertise, bridges engineering prowess with fundamental research, propelling the boundaries of gravimetric Earth observation and reference system realization.
Objectives
The objectives are grouped into three primary areas, reflecting its working groups:
1. Atom interferometry for ground-based and space-based gravimetry (quantum gravimetry) will offer a wide range of applications. This includes rapid local gravimetric surveys, exploration activities, and the monitoring of gravimetric Earth system processes with exceptional spatial and temporal resolution. In space, atom interferometry will revolutionize accelerometry and inertial sensing. Combining atom interferometry with electrostatic accelerometers in hybrid systems could broaden the spectral range for future inertial sensing and navigation endeavors. Its impact will extend to satellite navigation enhancement and the development of next-generation gradiometer missions (such as GOCE follow-on).
2. Laser-interferometric ranging between test masses in space, with nanometer precision, represents another groundbreaking development. This technology, originally designed for gravitational wave detection and validated in missions like LISA/-Pathfinder, is being adapted for geodetic measurements, as demonstrated by GRACE-FO. Further refinements, such as tracking satellite swarms, may become feasible in the coming years. Optical techniques may also find application in future accelerometers for test mass sensing and advanced space-based gradiometry.
3. Frequency comparisons of highly precise optical clocks interconnected via optical links offer insights into differences in gravity potential over significant distances (relativistic geodesy). In the future, relativistic geodesy employing clocks will reassess how height systems are defined and realized, both locally and globally. Clock measurements will also furnish long-wavelength gravity field data and enhance the accuracy of the International Atomic Time standard (TAI). They are crucial for allspace geodetic techniques and for establishing and connecting reference systems. Additionally, high-performance clock networks could support Global Navigation Satellite Systems (GNSS).
In all three research domains, alongside with the advancements in measurementsystems and techniques, it is imperative to establish robust theoretical foundations for analysis models. This necessitates dedicated geodetic and relativistic modeling of the various gravity field parameters and measurement concepts involved.
Program of Activities
The IAG project QuGe fosters and encourages research in the areas of its working groups by facilitating the exchange of information and organizing workshops and sessions, either independently or at major inter-disciplinary conferences such as EGU, AGU, COSPAR, IAG Scientific Assembly and Symposia, and IUGG General Assembly. QuGe will endeavour to improve its visibility and demonstrate the benefit of the new technologies in geodesy and beyond. Within its scope, QuGe will continue contributing to related research activities and missions studied and pushed forward by NASA, ESA, EU and national programson the use of quantum technology. Examples are the missions MAGIC, CARIOQA, ACES. QuGe will strengthen the contacts to industry, enabling good exchange with science, while the major focus of QuGe will remain on research.
The activities of its working groups, as described below, constitute the activities of the Project, which will be coordinated by the Steering Committee and summarized in annual reports to the IAG Bureau. Project QuGe and its WGs will closely collaborate with other components of IAG such as specific Joint Study/Working Groups of the IAG commissions, ICCC and ICCT as well as with related services like IERS. Moreover, representatives of external bodies (e.g., from industry or research institutions) will collaborate in the WGs.1.3
Structure
Working Groups
WG Q.1 Quantum gravimetry in space and on ground
Chair: Franck Pereira (France)
WG Q.2 Laser interferometry for gravity field missions
Chair: Samuel Francis (USA)
WG Q.3 Relativistic geodesy with clocks
Chair: Jakob Flury (Germany)
References
[1] van Camp M, dos Santos FP, Murböck M, et al (2021) Lasers and ultracold atomsfor a changing earth. Eos, Transactions American Geophysical Union 102. https://doi.org/10.1029/2021EO2106738