Research and Projects

The geoid is Earth’s physical reference surface for height, i.e., the shape the oceans would take under gravity alone. Determining it accurately is one of the fundamental problems of physical geodesy.
Our research develops rigorous regional and national geoid models using the Stokes–Helmert approach and one-step integration of gravity observations from ground, airborne, and satellite sources. We focus on how topography, measurement noise, and data gaps affect geoid accuracy, including the potential for sub-centimetre determination where data quality allows.
This work is implemented in OSVGeo (One-Step integration Vector Geoid Determination), our software for regional and national geoid modelling. We also support geoid determination and provide OSVGeo training using real-world test cases, including Auvergne, France, and Colorado, USA. [Learn more about OSVGeo and training by clicking the link below]

We are changing what gravity field models are built for, from determining height to serving as a position reference where satellite navigation cannot be relied on. GNSS signals can be jammed, spoofed, or simply unavailable underground, underwater, and at high latitudes. Gravity offers an alternative that cannot be switched off and can be used for resilient positioning, navigation, and timing (PNT) in GNSS-denied areas.
Quantum sensors, measuring the gravity and magnetic fields of the Earth, have now become accurate enough to make this practical. The reference maps they must match against have not kept pace, and that is where our work sits: building reference gravity and magnetic models good enough to position with, and understanding what such models need to deliver. Existing models were built to describe a surface, not the three-dimensional space that aircraft, vessels, and vehicles actually move through, so part of the task is extending them upward and downward and identifying what the available data can and cannot resolve? Answering it sets the requirements in both directions, what a reference model must achieve, and what accuracy and stability a sensor and its platform must reach to be useful.
We pursue this with partners across government, defence, and industry, and are training students with expertise in both geodesy and positioning.

Countries are modernizing the reference systems that define position and height, replacing legacy survey networks and fragmented vertical datums with satellite- and gravity-based frameworks.
Our research supports this transition by connecting old and new coordinate systems, unifying vertical datums across land and water, validating geoid-based heights, and modelling ground motion in four-dimensional reference frames. We also integrate modern elevation and water-surface datasets, including DEMs and SWOT observations, to improve height consistency across terrestrial, coastal, and marine environments.
Canada is a current example, with NAD83 being replaced by NATRF2022 and height systems increasingly tied to modern geoid models.