Preliminary Assessment of Strap-down Operation of a Gravity Gradient Quantum Sensor in Maritime Contexts

Adam Seedat, Andrew Hinton, Farzad Hayati, Jonathan Winch, Andrew Lamb, Sanaz Roshanmanesh, Sha Luo, Thomas King, Nicole Metje, Kevin Ridley, and Michael Holynski

Peer Reviewed

Abstract:	The prevalence of the Global Navigation Satellite System (GNSS) has made it a ubiquitous tool for navigators. However, the presence of GNSS-denied environments created by high-density media in satellite-receiver lines-of-sight or by deliberate signal interference is a key barrier to robust navigation, particularly in maritime contexts for navigating underwater and autonomous shipping. Whilst an inertial navigation system (INS) can be an important navigation tool in GNSS-denied environments, such systems are prone to drift-induced readout errors, resulting in a loss of positional accuracy over time. In this article, we discuss the potential use of quantum sensors for alternative navigation via gravity gradient map matching to enable stable navigation trajectories. Through their ability to reject specific inertial noise sources, atom interferometers have potential as an interesting sensor technology in such contexts. However, while atom interferometers have demonstrated performance relevant to map matching in static conditions, a key barrier is improving their deployability on dynamic platforms. We here provide initial reports on two maritime demonstrations of gravity gradiometry via atom interferometry in a strap-down configuration, showing the realization of gravity gradiometry on a moving marine vessel without any inertial stabilization. We provide an overview of the trials and the impact of the maritime vessel and inertial environments on the interferometer performance. These trials are a first step towards a full alternative navigation capability, which will require further work on sensor robustness across different inertial conditions, sensor integration into the platform, and integration into the navigation system via filtering. The trials are informing a granular understanding of the challenges of operating in these environments, progressing the roadmap towards further demonstrations and upgrades for the next generation of sensors to bring benefit to maritime navigators. Index Terms—quantum sensing, atom interferometry, gravity gradient, map matching, maritime, alternative navigation.
Published in:	2025 IEEE/ION Position, Location and Navigation Symposium (PLANS) April 28 - 1, 2025 Salt Lake Marriott Downtown at City Creek Salt Lake City, UT
Pages:	91 - 96
Cite this article:	Seedat, Adam, Hinton, Andrew, Hayati, Farzad, Winch, Jonathan, Lamb, Andrew, Roshanmanesh, Sanaz, Luo, Sha, King, Thomas, Metje, Nicole, Ridley, Kevin, Holynski, Michael, "Preliminary Assessment of Strap-down Operation of a Gravity Gradient Quantum Sensor in Maritime Contexts," 2025 IEEE/ION Position, Location and Navigation Symposium (PLANS), Salt Lake City, UT, April 2025, pp. 91-96.
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