Norwegian Subsea | High-precision Motion Reference Units (MRUs)

Market-leading Motion Reference Units for marine and subsea applications

An MRU, or Motion Reference Unit, is a device used to measure and record the movements of a vessel or object in all six degrees of freedom: roll, pitch, yaw, surge, sway, and heave.

MRUs are key components in control and monitoring of helidecks, offshore gangways, cranes, winches, sonars, ships, buoys, and many other applications.

Find out how it works

Tested and validated in real sea conditions

Many suppliers tend to present test data solely for simple regular motions observed in laboratory conditions. At sea, vessels experience irregular and coupled motions.

While most sensors perform well in sine wave motion, only a select few excel in irregular sea conditions.

Our MRUs stand out as they consistently deliver exceptional performance across all conditions.

Our advantages

High Accuracy

Market leading accuracy in real sea conditions.

Affordable

High performance in all conditions at affordable prices set the Norwegian Subsea MRUs apart from the competition.

Easy to use

Our small and lightweight MRUs, with flexible cable options, are easy to install with the MRU configurator for effortless integration.

Our products

Norwegian Subsea produces industry-leading Motion Reference Units (MRUs) for marine, subsea and wind energy applications. Our MRUs are robust and affordable, and offer high-accuracy performance, along with a plug-and-play interface.

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Use cases for our Motion Reference Unit solutions

Our MRUs are versatile and well-suited for a wide range of applications and usage scenarios.

Motion monitoring

Safe landing of helicopters, ship and cargo stability, monitoring of ships, risers, or wind turbines. Motion measurements can be used in real-time to monitor safe operating conditions, as an input to a digital twin model or as an input to AI algorithms. In all these circumstances, reliable and accurate motion data is paramount.

Motion control

By actively compensating for heave motion, marine MRUs enable improved stability, control, and operational efficiency for offshore operations such as crane operations, subsea installations, and other tasks that require precise positioning and motion control in challenging sea conditions.

Instrument compensation

By accounting for factors such as sensor misalignments, offsets, and drift, instrument compensation enhances the precision of marine MRUs in capturing and analyzing vessel motions, enabling more accurate data for a range of marine applications including navigation, research, and structural monitoring.

Trusted by industry leaders

Over 1200 Norwegian Subsea Motion Reference Units are in operation world-wide on over 600 vessels, floating and subsea structures.

Some selected customer references.

Where our MRUs are used

Applications

Norwegian Subsea Motion Reference Units can be used in a variety of marine, subsea and wind energy applications.

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example applications of norwegian subsea products

Latest case studies

Light Structures

Making Structural Health Monitoring smarter with Motion Reference Units

As the maritime industry accelerates its journey towards smarter, more efficient digital operations, structural health monitoring systems are playing a central role in operational efficiency, safety and sustainability. These systems increasingly depend on real-time, high-fidelity data from Motion Reference Units (MRUs) to contextualise structural stresses with the vessel’s motion in a given sea state. This is especially important in meeting the evolving requirements of classification society SMART notations from bodies such as the American Bureau of Shipping (ABS) and DNV.

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ShoreConnection International

ShoreConnection ensures safe landing for thousands of helicopters with Norwegian Subsea Motion Reference Units

Helideck Motion Monitoring & Weather Data Systems (HMS) provide real-time motion and environmental data essential for flight planning and for pilots to remain in safe control during take off and landing from moving helidecks. The HMS depends on Motion Reference Units (MRU) installed directly on to the support structure that continuously measure the helideck’s movement. Leading HMS manufacturer ShoreConnection chooses MRUs built by Norwegian Subsea.

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Ultrabeam Hydrographic

Ultrabeam Hydrographic enhances high-resolution 3D surveys with Norwegian Subsea Motion Reference Units

Ultrabeam, a specialist in hydrographic survey and underwater inspection, relies heavily on precise motion compensation to ensure accuracy in their 3D mapping projects. By integrating Norwegian Subsea’s compact, calibration-free Motion Reference Units (MRUs), Ultrabeam has significantly improved its survey data accuracy, while enjoying simplified integration, and enhanced operational efficiency in diverse surveying environments, from bridges, to offshore installations.

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Latest news

A year in Motion Reference Units...

From bathymetric surveys to subsea inspections and wave radar systems, our Motion Reference Units (MRUs) have been put to work in a wide range of challenging environments during 2025. As the year draws to a close we take a quick look back at some of the highlights, applications, and collaborations that helped shape another strong year of progress for Norwegian Subsea.

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Connecting with the Chinese Maritime Sector at Marintec 2025

Norwegian Subsea has returned from a successful trip to Shanghai, where our compact Motion Reference Units (MRUs) drew strong interest from across the Chinese maritime supply chain during the Marintec China 2025 exhibition. As one of the world’s leading maritime events, Marintec provided an ideal platform to engage with shipbuilders, integrators and equipment manufacturers in a region where innovation and scale go hand in hand.

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Motion Reference Units for vessel performance optimisation in focus at Europort 2025

Next week, the maritime world gathers in Rotterdam for Europort 2025, one of the largest international meeting points for shipbuilders, technology providers and operators. With a strong focus on innovation and sustainability, the exhibition is an important platform for discussing how the industry can meet future demands through smarter, greener solutions.

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