What makes our Motion Reference Units so accurate in real sea conditions?

Discover the unique advantages that set our MRUs apart from others in the Industry.

How it works

An Motion Reference Unit (MRU) 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.

Icons of ships with illustrations of Roll, Pitch, Yaw and Heave, Surge and Sway

How do we achieve this?

MEMS sensors + Sensor Fusion Algorithms = High Accuracy at low cost

MEMS sensors

Advances in MEMS technology
gyroscopes and accelerometers
enable new high accuracy sensors
at low cost

+ Sensor Fusion Algorithms

Our unique advanced sensor fusion algorithms get the most out of the best
available sensors to provide great results under realistic circumstances

= High Accuracy at low cost

High Accuracy in Real
Sea Conditions

Tested in real sea conditions

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

Read more about how we validate our MRU

Easy to use

All Norwegian Subsea Motion Reference Units (MRUs) can be easily configured using the MRU Configurator (free of charge).

Simply define the communication ports and protocols as well as the MRU mounting orientation and location, and you are ready to go.

The MRU Configurator is also a great tool to monitor the outputs in real-time, plot the variables, check the on-board diagnostics and update the MRU firmware.

Read more about the MRU Configurator

Cost-effective excellence

At our company, we are committed to delivering top-of-the-line Motion Reference Units that combine exceptional quality with cost-effectiveness. Our unwavering focus on optimizing value enables us to cut upfront expenses and reduce maintenance costs, ensuring maximum savings for your operations.

Our products

MRU Marine

Usage area

50 m depth, IP 68

Heave accuracy

5 cm or 5.0%

Roll & Pitch accuracy

3000±0.05°
6000±0.02°
9000±0.01°

Connectors

Lemo or SubConn 8 or SubConn 16

Learn more

MRU Compact

Usage area

IP 65

Heave accuracy

5 cm or 5.0%

Roll & Pitch accuracy

3000±0.05°
6000±0.02°
9000±0.01°

Connectors

RJ45 or RJ50

Learn more

MRU Subsea

Usage area

6000 m depth

Heave accuracy

5 cm or 5.0%

Roll & Pitch accuracy

3000±0.05°
6000±0.02°
9000±0.01°

Connectors

SubConn 8

Learn more

MRU Ex

Usage area

Hazardous areas

Heave accuracy

5 cm or 5.0%

Roll & Pitch accuracy

3000±0.05°
6000±0.02°
9000±0.01°

Connectors

Pigtail cable

Learn more

Download product brochure

Some of the applications where our MRU Marine are used

Sonar Motion Compensation

Accurate measurements of roll, pitch, and heave are crucial for achieving optimal results when compensating sonar systems for vessel motion, without relying on GNSS or RTK.

Active Heave Compensation

Accurate measurement of vertical motion at the crane tip or winch is crucial for the operation of Active Heave Compensated (AHC) cranes and winches.

Dynamic Positioning

Dynamic positioning (DP) of vessels necessitates roll and pitch compensation of the GNSS antenna to ensure accurate positioning of the ship's control point.

Ship Motion Monitoring

Precise motion measurements are essential for vessel digitalisation, supporting fuel optimisation, route planning, cargo safety and structural health.

Helideck Monitoring

Accurate measurement of roll, pitch, and heave motions is crucial for assessing the safety of helidecks during helicopter landing and take-off operations.

Wave Radar

Accurate heave measurements play a vital role in compensating for Wave Radar measurements when installed on ships or other floating vessels.

All applications

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

Related articles and case studies

Advanced motion compensation for sonars introduced at Ocean Business 2025

Norwegian Subsea is bringing its acclaimed Motion Reference Unit (MRU) technology to sonar-based applications with the introduction of an updated MRU lineup featuring full aiding capabilities at Ocean Business 2025 this week.

Read article

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.

Read case study

WASSP Boosts Multibeam Accuracy for Marine Survey and Fish Finding with Norwegian Subsea Motion Reference Units

Norwegian Subsea’s Motion Reference Units (MRUs) are now available integrated with WASSP’s multibeam sonar systems, offering enhanced motion data accuracy and performance for offshore applications.

Read article

All articles All case studies

What makes our Motion Reference Units so accurate in real sea conditions?

How it works

How do we achieve this?

MEMS sensors

+ Sensor Fusion Algorithms

= High Accuracy at low cost

Tested in real sea conditions

Easy to use

Cost-effective excellence

Our products

MRU Marine

Usage area

Heave accuracy

Roll & Pitch accuracy

Connectors

MRU Compact

Usage area

Heave accuracy

Roll & Pitch accuracy

Connectors

MRU Subsea

Usage area

Heave accuracy

Roll & Pitch accuracy

Connectors

MRU Ex

Usage area

Heave accuracy

Roll & Pitch accuracy

Connectors

Some of the applications where our MRU Marine are used

Sonar Motion Compensation

Active Heave Compensation

Dynamic Positioning

Ship Motion Monitoring

Helideck Monitoring

Wave Radar

Trusted by industry leaders

Related articles and case studies

Advanced motion compensation for sonars introduced at Ocean Business 2025

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

WASSP Boosts Multibeam Accuracy for Marine Survey and Fish Finding with Norwegian Subsea Motion Reference Units

Contact us

How do we achieve this?

MEMS sensors

+ Sensor Fusion Algorithms

= High Accuracy at low cost

Tested in real sea conditions

Easy to use

Cost-effective excellence

Our products

MRU Marine

Usage area

Heave accuracy

Roll & Pitch accuracy

Connectors

MRU Compact

Usage area

Heave accuracy

Roll & Pitch accuracy

Connectors

MRU Subsea

Usage area

Heave accuracy

Roll & Pitch accuracy

Connectors

MRU Ex

Usage area

Heave accuracy

Roll & Pitch accuracy

Connectors

Some of the applications where our MRU Marine are used

Sonar Motion Compensation

Active Heave Compensation

Dynamic Positioning

Ship Motion Monitoring

Helideck Monitoring

Wave Radar

Trusted by industry leaders

Related articles and case studies