First demonstration of long-time absolute atomic gravity measurement trials in open sea areas

Abstract

High-precision gravimetric measurement constitutes a foundational capability for geodesy, geophysical exploration, resource prospecting, and navigation systems. Current marine gravimetric systems employing relative gravimeters encounter inherent limitations due to progressive zero-point drift and obligatory recalibration requirements, constraining sustained oceanic operational capacity. Atomic interferometric gravimeters offer a paradigm-shifting solution, though previous validation efforts remained restricted to static/moored configurations or brief coastal deployments without verified long-term dynamic performance. This study details absolute gravity measurements obtained through transoceanic campaigns across Pacific, Atlantic, and Indian Ocean using atomic interferometry. Repeat-line experiments under challenging sea conditions (Sea State 3–4) yielded internal consistency better than 0.33 mGal (1 mGal = 10⁻⁵ m/s²), quantified by the root mean square of gravity differences along repeated survey lines. Comparative analyses demonstrate operational superiority over conventional relative gravimeters, maintaining drift-free performance during seven-month transoceanic campaigns with closed-loop verification. To the best of our knowledge, this experiment demonstrates one of the best reported levels of repeat-line agreement for shipborne atomic absolute gravity measurements under dynamic open-sea conditions, together with the longest sustained operational duration and the farthest voyage range reported in the open literature. This breakthrough transitions from validation to deployment, enabling advanced underwater navigation and facilitating deep-sea exploration, marine dynamics research, and the development of marine absolute gravity reference networks and improved global marine gravity field models.