MRU Subsea
The NORSUB MRU SUBSEA is an ideal choice for accurate and robust subsea motion measurements. With a depth rating of up to 6000 meters, this compact and small-sized motion sensor offers versatility in installation.
MRU Subsea
The NORSUB MRU SUBSEA is an ideal choice for accurate and robust subsea motion measurements. With a depth rating of up to 6000 meters, this compact and small-sized motion sensor offers versatility in installation.
Roll and pitch dynamic accuracy of 0.05° Heave accuracy: 5 cm / 5 %
The 6000 series provides high performance 0.02° roll and pitch accuracy
The 9000 series achieves exceptional precision with 0.01° roll and pitch accuracy
The MRU Subsea can be easily placed in various locations due to its small size and footprint. Communication options include ethernet, RS-232, and RS-485/422, while power and communication are facilitated through the Subconn connector.
For enhanced functionality, the Subsea MRU can be equipped with a high-end magnetometer, ensuring precise magnetic heading measurements.
The Subsea MRU is available in three versions, 3000, 6000, and 9000, to cater for different accuracy requirements and budgets.
Additionally, the Subsea MRU is offered in an inclinometer version that focuses on continuous monitoring of the roll/pitch angle of subsea templates at a lower cost. This eliminates the need for expensive subsea rentals during installation.
High accuracy roll, pitch and heave, even in irregular sea states.
Low weight and small footprint make installation and handling easy.
Depth rating at 6000 m enables motion measurements in ultra deep waters.
6000 m water depth
Titanium
76 mm x 76 mm x 165 mm
1.2 kg
SubConn 8-pin FCR1508M
Ethernet & RS-232, Ethernet & 2-wire RS-485
TCP, UDP, Modbus TCP, ethernet/IP
0-100 Hz
3000 series: 0.05°
6000 series: 0.02°
9000 series: 0.01°
RMS (dynamic & static)
5.0 cm or 5.0 %
Whichever is greater for 0 to 25 s periods, valid for irregular motions in real sea conditions
± 0.5 °
Magnetic heading
3000 series: ± 150 °/s
6000 series: ± 450 °/s
9000 series: ± 450 °/s
± 3 g (3000 series) / ± 4 g (6000 series) / ± 10 g (9000 series)
± 50 m
± 180 ° / ± 90 ° / ± 360 °
(no limits)
0 - 100 Hz
(adjustable output frequencies)
0.2 % max/min
3000 series: 0.050 °/s RMS
6000 series: 0.025 °/s RMS
9000 series: 0.015 °/s RMS
3000 series: 0.0025 m/s2 RMS
6000 series: 0.0020 m/s2 RMS
9000 series: 0.0015 m/s2 RMS
0.01 m/s2 RMS
6 W
9 - 36 V DC (24 V nominal)
32 GB
Custom NMEA, ASCII and Binary, Atlas, Gyrocompas 1, Ifremer Victor, MDL, NORSUB 1-8, Simrad EM 3000, SMCA, SMCC, Tokimek PTVG, RDI ADCP, TSS1 and many more.
Read more
GET/SET through telnet, serial port and MRU configurator.
Read more
Sync to host PC, Sync to NTP server, Sync to PPS
Operating: -40 to +70 °C
Storage: -40 to +85 °C
IEC 60945/EN 60945
(immunity/emission)
IEC 60945/EN 60945
2000 m/s2 (half-sine 0.5 msec)
non-operational (10 ms peak)
100 000 h
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.
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.
Subsea surveys often demand precise tilt measurements (roll and pitch) for various purposes, such as installation tasks or continuous monitoring of tilt changes and deflections in subsea structures.
Reliable motion sensors are vital components in the navigation system and motion compensation of payload sensors for ROVs and AUVs.
Monitoring the movements and structural integrity of floating wind foundations, including both the base and turbine, along with the anchoring system, is crucial.
The NORSUB Subsea MRU is specifically designed to provide highly accurate measurements of roll, pitch (inclination), and lateral motions in risers.
Accurate motion sensors play a crucial role in the structural monitoring of Blowout Preventers (BOPs), enabling the measurement of inclination and lateral displacements.
Over 1200 Norwegian Subsea Motion Reference Units are in operation world-wide on over 600 vessels, floating and subsea structures.
Some selected customer references.
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More than a month has passed since Oceanology International 2026, giving us time to reflect on the value of this major ocean technology and marine science event. For Norwegian Subsea, the London exhibition was defined by a wide range of conversations with both familiar and new faces, many of which are now developing into ongoing discussions across key marine and subsea applications.
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.
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.