Motion Reference Units (MRU) and Wave Sensors (WS)

Motion Reference Units

The Motion Reference Unit (MRU) product line was first released in 2004 when Inertial Labs MEMS-based sensor solutions began to compete in performance with traditional FOG units. Easy integration of the MRU product line for the end user means competitive performance at no extra cost.

Factory configured to output parsed data using Inertial Labs message formats or Kongsberg/Seatex. Teledyne TSS* data formats allow users to replace dated MRUs with the Inertial Labs product line easily.

Inertial Labs developed the MRU to meet requirements for all marine and hydrographic applications. The MRU is a high-performance strap-down Motion Sensor that determines Pitch & Roll, Heave, Surge, Sway, Linear acceleration, Angular Rates, Heading, Velocity, and Position for any device on which it is mounted to.

The Inertial Labs team of skilled engineers provides expertise to help users select and configure from the models available: MRU-B1, MRU-B1.1, MRU-B2, MRU-E, MRU-P and MRU-PD (with subsea models available). Our support team helps set up units for all application bases to satisfy GNSS-enabled and GNSS-denied environments.

MRU compass
Inertial Labs MRU – Motion Reference Unit - American Bureau of Shipping - ABS Certified Logo
MRU buoy

Wave Sensors

The Inertial Labs Wave Sensor (WS) product line is the latest tactical-grade MEMS-based inertial sensor solutions release. In 2016 Inertial Labs responded to the research and development sectors of many biology and geographic analysis facilities for a device that can monitor Ocean Characteristics for Maritime Observation and Analysis. Inertial Labs has developed its Wave Sensors (WS) to meet industry wave statistics requirements and generate spectral data as complete Fourier coefficients and energies set.

The Wave Sensor (WS) products are an enhanced, high-performance strap-down Wave, Direction, and Motion Sensor that determines Significant Wave Height, Max Wave Height, Wave Period, Wave Direction, Wave Energy, Directional Width, Fourier Coefficients, Mean Spread Angle, Heading, Pitch, Angular Rates, Accelerations, Magnetometer Data, Temperature, Heave, Heave Velocity and Position for any device on which it is mounted to.

The Inertial Labs team of skilled engineers provides expertise to help users select and configure from the models available: WS-E and WS-PD. Our support team helps set up units for all application bases to satisfy GNSS-enabled and GNSS-denied environments.

MRU Models

MODEL
MRU-B1 MRU-B1.1 MRU-B2 MRU-E MRU-P MRU-PD
Output Signals Heave, Surge and Sway Pitch and Roll Heave, Surge, Sway, Pitch and Roll Heave, Surge, Sway, Heading, Pitch and Roll Heave, Surge, Sway, Heading, Pitch, Roll, Position and Velocity Heave, Surge, Sway, Dual Antenna Heading, Pitch, Roll, Position and Velocity
Heave Accuracy 5% or 5 cm (RMS) - 5% or 5 cm (RMS) 5% or 5 cm (RMS) 5% or 5 cm (RMS) 5% or 5 cm (RMS)
Heading Type - - - Embedded Fluxgate Magnetometer Embedded Fluxgate Magnetometer Dual Antenna GNSS, External Magnetic Compass (optional)
Pitch & Roll Accuracy - 0.02 degrees (RMS) 0.02 degrees (RMS) 0.02 degrees (RMS) 0.02 degrees (RMS) 0.02 degrees (RMS)
Heading Accuracy - - - 0.6 degrees (RMS) 0.4 degrees (RMS) 0.05 degrees (RMS)
Position Accuracy - - - - 40 cm (DGPS), 1 cm (RTK) 40 cm (DGPS), 1 cm (RTK)
Size (mm) 120 x 50 x 53 120 x 50 x 53 120 x 50 x 53 120 x 50 x 53 120 x 50 x 53 120 x 50 x 53
Weight (gram) 220 220 220 280 320 320
Applications Marine Loading Dock; Platform Heave Compensation Crane Rotation Compensation; Nearshore Drilling Platform Survey Vessel Motion Analysis; Offshore Refinery Motion Control Marine Antenna Pointing; Helideck Stabilization Monitoring Cargo Transfer Stabilization; DP-1/2/3 Buoys; Small Craft Positioning Vessel Navigation; Autonomous Survey Craft; Dynamic Positioning System
Model MRU-B1 MRU-B1.1 MRU-B2 MRU-E MRU-P MRU-PD
Datasheet, PDF
MODEL
MRU-B1 MRU-B1.1 MRU-B2 MRU-E MRU-P MRU-PD
Output Signals Heave, Surge and Sway Pitch and Roll Heave, Surge, Sway, Pitch and Roll Heave, Surge, Sway, Heading, Pitch and Roll Heave, Surge, Sway, Heading, Pitch, Roll, Position and Velocity Heave, Surge, Sway, Dual Antenna Heading, Pitch, Roll, Position and Velocity
Heave Accuracy 5% or 5 cm (RMS) - 5% or 5 cm (RMS) 5% or 5 cm (RMS) 5% or 5 cm (RMS) 5% or 5 cm (RMS)
Heading Type - - - Embedded Fluxgate Magnetometer Embedded Fluxgate Magnetometer Dual Antenna GNSS, External Magnetic Compass (optional)
Pitch & Roll Accuracy - 0.02 degrees (RMS) 0.02 degrees (RMS) 0.02 degrees (RMS) 0.02 degrees (RMS) 0.02 degrees (RMS)
Heading Accuracy - - - 0.6 degrees (RMS) 0.4 degrees (RMS) 0.05 degrees (RMS)
Position Accuracy - - - - 40 cm (DGPS), 1 cm (RTK) 40 cm (DGPS), 1 cm (RTK)
Size (mm) 120 x 50 x 53 120 x 50 x 53 120 x 50 x 53 120 x 50 x 53 120 x 50 x 53 120 x 50 x 53
Weight (gram) 220 220 220 280 320 320
Applications Marine Loading Dock; Platform Heave Compensation Crane Rotation Compensation; Nearshore Drilling Platform Survey Vessel Motion Analysis; Offshore Refinery Motion Control Marine Antenna Pointing; Helideck Stabilization Monitoring Cargo Transfer Stabilization; DP-1/2/3 Buoys; Small Craft Positioning Vessel Navigation; Autonomous Survey Craft; Dynamic Positioning System
Model MRU-B1 MRU-B1.1 MRU-B2 MRU-E MRU-P MRU-PD
Datasheet, PDF

Wave Sensor Models

MODEL
WS-E WS-PD
Wave Sensor WS-E Enhanced GPS Aided Wave Sensor WS-PD Professional Dual
Output Signals Wave Energy, Spectral Data, Fourier Coefficients, Attitude Wave Energy, Spectral Data, Fourier Coefficients, Attitude, Position and Velocity
Wave Direction Accuracy 1 degrees (RMS) 0.5 degrees (RMS)
Pitch & Roll Accuracy 0.02 degrees (RMS) 0.02 degrees (RMS)
Heading Accuracy 0.6 degrees (RMS) 0.05 degrees (RMS)
Position Accuracy - 40 cm (DGPS), 1 cm (RTK)
Heading Type Embedded Fluxgate Magnetometer Dual Antenna GNSS
Size (mm) 120 x 50 x 53 120 x 50 x 53
Weight (gram) 320 320
Applications Research Buoy, Wave Direction and Energy Analysis Wave and Ocean Surge Tracking, Ocean Current and Tide Analysis
Model WS-E WS-PD
Datasheet, PDF

Subsea MRU and WS Enclosed Options

MODEL
MRU-B1S MRU-B1.1S MRU-B2S MRU-PDS WS-PDS
Output Signals Heave, Surge and Sway Pitch and Roll Heave, Surge, Sway, Pitch and Roll Heave, Surge, Sway, Dual Antenna Heading, Pitch, Roll, Position and Velocity Wave Energy, Spectral Data, Fourier Coefficients, Attitude, Position and Velocity
Heave Accuracy 5% or 5 cm (RMS) - 5% or 5 cm (RMS) 5% or 5 cm (RMS) -
Depth Rating 1000 meters 1000 meters 1000 meters - -
Heading Type External Magnetic Compass (optional) External Magnetic Compass (optional) External Magnetic Compass (optional) Dual Antenna GNSS Dual Antenna GNSS
Pitch & Roll Accuracy - 0.02 degrees (RMS) 0.02 degrees (RMS) 0.02 degrees (RMS) 0.02 degrees (RMS)
Heading Accuracy - - - 0.05 degrees (RMS) 0.05 degrees (RMS)
Position Accuracy - - - 40 cm (DGPS), 1 cm (RTK) 40 cm (DGPS), 1 cm (RTK)
Wave Direction Accuracy - - - - 0.5 degrees (RMS)
Size (mm) 245 x 140 x115 245 x 140 x115 245 x 140 x115 245 x 140 x 115 245 x 140 x 115
Weight (gram) 6570 6570 6570 6500 6500
Applications Echosounder Scanning System; Subsea Heave Compensation Bathymetric Survey; Subsea Lever Rotation Subsea Hydrography; Submersible Vessel Orientation Compensation Vessel Navigation; Autonomous Survey Craft; Dynamic Positioning System Wave and Ocean Surge Tracking, Ocean Current and Tide Analysis
Model MRU-B1S MRU-B1.1S MRU-B2S MRU-PDS WS-PDS
Datasheet, PDF
MODEL
MRU-B1S MRU-B1.1S MRU-B2S MRU-PDS WS-PDS
Output Signals Heave, Surge and Sway Pitch and Roll Heave, Surge, Sway, Pitch and Roll Heave, Surge, Sway, Dual Antenna Heading, Pitch, Roll, Position and Velocity Wave Energy, Spectral Data, Fourier Coefficients, Attitude, Position and Velocity
Heave Accuracy 5% or 5 cm (RMS) - 5% or 5 cm (RMS) 5% or 5 cm (RMS) -
Depth Rating 1000 meters 1000 meters 1000 meters - -
Heading Type External Magnetic Compass (optional) External Magnetic Compass (optional) External Magnetic Compass (optional) Dual Antenna GNSS Dual Antenna GNSS
Pitch & Roll Accuracy - 0.02 degrees (RMS) 0.02 degrees (RMS) 0.02 degrees (RMS) 0.02 degrees (RMS)
Heading Accuracy - - - 0.05 degrees (RMS) 0.05 degrees (RMS)
Position Accuracy - - - 40 cm (DGPS), 1 cm (RTK) 40 cm (DGPS), 1 cm (RTK)
Wave Direction Accuracy - - - - 0.5 degrees (RMS)
Size (mm) 245 x 140 x115 245 x 140 x115 245 x 140 x115 245 x 140 x 115 245 x 140 x 115
Weight (gram) 6570 6570 6570 6500 6500
Applications Echosounder Scanning System; Subsea Heave Compensation Bathymetric Survey; Subsea Lever Rotation Subsea Hydrography; Submersible Vessel Orientation Compensation Vessel Navigation; Autonomous Survey Craft; Dynamic Positioning System Wave and Ocean Surge Tracking, Ocean Current and Tide Analysis
Model MRU-B1S MRU-B1.1S MRU-B2S MRU-PDS WS-PDS
Datasheet, PDF

Use Cases

Inertial Labs MRU Motion Reference Unit Application - Marine Vessel Navigation

Marine Vessel Navigation

Easily paired with onboard Autopilot systems and controllers, the MRU product line features two widely used models for Navigation systems aboard vessels. The Professional version of the MRU (MRU-P) features a single antenna GNSS receiver for position and velocity calculations. Similarly, the Professional Dual Antenna MRU-PD can calculate precise position and velocity, and heading with an accuracy of 0.05 degrees (RMS), making it the ideal solution for navigation on any sized marine platform.

Hydrographic and Bathymetric Surveying

Bathymetric or Hydrographic surveys are survey methods used for submarine topography that have been implemented to observe marine landscapes and structures for several decades. The Inertial Labs MRU can be used with single beam and multibeam echo-sounders (SBES or MBES) and other external sensors using industry-wide accepted sentence formats (NMEA and TSS-1), where it directly passes information to internal algorithms while operating. This makes the MRU the ideal solution, especially for Hydrographic and Bathymetric surveying applications.

Inertial Labs MRU Motion Reference Unit Application - Hydrographic and Bathymetric Surveying
Inertial Labs MRU Application - Cargo Transfer and Loading Stabilization - Remotely Operated Underwater Vehicle (ROV)

Cargo Transfer and Loading Stabilization (ROV)

Effectively communicating motion and navigation parameters (position, velocity, heave, surge, and sway) for proper heave compensation while loading and unloading cargo and marine equipment is essential in most shipping industries. Whether the system is fully automated or dependent on user response, having a device that can be easily installed to replace a dated unit is where Inertial Labs stands out compared to competitors. Inertial Labs builds modular and custom solutions using commonly used interfaces and data formats.

Research Vessels and Buoys

Research vessels and buoys may need to run for weeks without interrupting data streams. Inertial Labs builds robust IP67 or subsea enclosed solutions with internal data-logging abilities to record post-processing or real-time monitoring data. Default solutions can be set up to stream data wirelessly to nearby base stations where research teams can use data to interpret ocean conditions.

Inertial Labs MRU Motion Reference Unit Application - Research Vessels and Buoys
Inertial Labs MRU Motion Reference Unit Application - Helideck and Offshore Drilling Monitoring

Helideck and Offshore Drilling Monitoring

The Motion Reference Unit is commonly used for modular captive marine vessels (MCV) and helideck monitoring (HMS), stabilizing platforms, and communicating with multiple other response systems to know how to compensate for the heave, surge, and sway of a vessel. Offshore oil drilling or ocean-based wind farm industries are other common markets where Inertial Labs can provide the sensor solutions required to account for motion in the ocean.

Autonomous Vessels (AUV and USV)

Autonomy has become the fastest-growing industry of this century. Autonomous Underwater Vessels (AUV) or Unmanned Surface Vehicles (USVs) can be used in military minesweeping in the ocean or commercial applications for underwater scanning and surveying. Inspection processes have now taken on the autonomous approach and the climate and environmental markets, especially when navigation solutions like the ones supplied by Inertial Labs are becoming increasingly more cost-effective.

Inertial Labs MRU Application - Autonomous Underwater Vessels (AUV) and Unmanned Surface Vehicles (USV)
Inertial Labs MRU Motion Reference Units - ACS880 Industrial Drives ACS880-01, ACS880-07, ACS880 Multidrive - Modbus/TCP

Integration with ABB ACS880 Winch Drives

Inertial Labs Motion Reference Units are fully integrated with ABB ACS880 winch drives for Offshore AHC and towing roll compensation. The ABB ACS880 winch drive and the MRU communicate over Ethernet Modbus TCP protocol with a watchdog timer for a failsafe system. Each MRU can communicate with up to two ACS880 drives in parallel for redundancy or as master/follower synchronized applications.

Ocean Characteristics Monitoring

The Wave Sensor meets industry wave statistics requirements and generates spectral data as complete Fourier coefficients and energies set. Use the WS to monitor and record or communicate using RF in real-time to a base station Wave Parameters and Ocean Characteristics such as Significant Wave Height, Max Wave Height, Wave Period, Wave Direction, Wave Energy, Directional Width, Fourier Coefficients, Mean Spread Angle and much more.

Inertial Labs MRU Motion Reference Unit Application - Ocean Characteristics Monitoring
Inertial Labs MRU Motion Reference Unit Application - Dynamic Positioning on Research Buoy’s and Vessels

Dynamic Positioning on Research Buoys and Vessels

Mount using the IP67 or Subsea enclosure (rated at least 200 meters) on research buoys and vessels (autonomous and manually operated). Communicate in real-time using Radio Frequencies (RF) or the WS-PD and pair with a Real-Time Kinematic (RTK) Base Station from Inertial Labs for RTK communications. Ideal for Dynamic Positioning (DP-1/2/3) applications requiring but not limited to all common GNSS constellations (GPS, GLONASS, GALILEO, BeiDou, QZSS, NAViC, AltBOC, SBAS, DGPS, RTK).

University Oceanology Studies

Partnering with colleges and universities around the globe, Inertial Labs offers the Wave Sensor and a development kit bundle that includes the sensor, all cables, and the Graphical User Interface, all with an educational discount. Many schools and research facilities have taken advantage of these bundles, including Texas A&M, Tel Aviv University, Penn State University, Nagaoka University of Technology, Virginia Tech, Quebec University, and Seoul National University.

Inertial Labs MRU Motion Reference Unit Application - University Oceanology Studies

Integrations with the MRU and WS

The Inertial Labs Motion Reference Unit and Wave Sensor have been designed to be compatible with several solutions. Integration is supported for Single Beam and Multi-Beam Echo-Sounders (SBES or MBES) for hydrographic or bathymetric surveying.

Additionally, please take advantage of already available sensors on your platform and integrate them with the MRU and WS product line to increase performance and navigational accuracy. Supported external sensors include Airspeed, Wind-speed, External Gyro-compass, Velocity Sources (Doppler Velocity Logs), and External GNSS Receivers (Single or Dual Antenna).

Inertial Labs MRU Motion Reference Unit HYPACK Support
HYPACK
QINSY

Supported Software

Inertial Labs supplies drivers and tools for easy integration with commonly used platforms such as Waypoint, LabVIEW, QiNSY and Hypack products.

SDK

Waypoint Website

A Software Development Kit (SDK) allows developers to customize the processing workflow to suit their customers or application.
Post-processing is an ideal solution for applications requiring highly accurate post-mission position, velocity, or attitude.

LabVIEW

LabVIEW Website

LabVIEW is a graphical programming environment engineers use to develop automated research, validation, and production test systems.

HYPACK

Inertial Labs MRU Motion Reference Unit and HYPACK

HYPACK Website

One of the world’s most widely used hydrographic surveying packages provides all the tools to design a survey, collect data, process it, reduce it, and generate final products.

QINSY

Inertial Labs MRU Motion Reference Unit and Qinsy

QINSY Website

Qinsy is a survey planning, acquisition, and real-time hydrographic data processing solution, supporting various industries, from simple single-beam surveys to complex offshore construction works.

Performance Characteristics for the INS

Heave Accuracy (10 Second and 20 Second Wave Period)

Inertial Labs MRU Motion Reference Unit Pitch Signal and Pitch Error Graph
Inertial Labs MRU Motion Reference Unit Heave Signal and Heave Error Graph

Dynamic Pitch and Roll Accuracy (20 Second Wave Period)

Inertial Labs MRU Motion Reference Unit Pitch Signal and Pitch Error Graph
Inertial Labs MRU Motion Reference Unit Roll Signal and Roll Error Graph

Heave, Pitch & Roll Dynamic Testing

MRU Certificate of Design Assessment

Inertial Labs MRU – Motion Reference Unit - American Bureau of Shipping - ABS Certified Logo

The American Bureau of Shipping representatives assessed design plans and data of all Inertial Labs MRU products. This assessment is a representation by the Bureau of the degree of compliance the design exhibits with applicable sections of their Rules. This PDA is intended for a product to be installed on an ABS-classed vessel, MODU, or facility which is in existence or under contract for construction.

Certificate number 19-HS1851412-PDA

Date 10 May 2019

Development Kits and Unboxing

IP67 Development Kit

OEM Development Kit

Unboxing the Motion Reference Unit

Trademark Legal Notice: All product names, logos, and brands are the property of their respective owners. All company, product, and service names used in this document are for identification purposes only. Use of these names, logos, and brands does not imply endorsement. ABS, BeiDou, Cobham Limited, EdgeTech, Galileo, GLONASS, GPS, Hexagon, HYPACK, IMAGENEX, Kongsberg Seatex, LabVIEW, Livox, Norbit, NovAtel, NovAtel Inertial Explorer, Ouster, Qinsy, Quanergy, QZSS, R2Sonic, RIEGL, ROCK Robotic, ROS, Septentrio, Ship Motion Control SMC, Teledyne TSS, u-blox, Velodyne, WAASP, Waypoint.

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