Robust, versatile and accurate for the marine industry
High performance data in all dynamic environments delivered in an IP66 or IP68 titanium casing

Marine motion sensors

Motion Reference Unit IMU-10x IMU-10x, IMU-00x
Roll, pitch, heave, velocities and
accelerations motion sensor.

Model Roll/Pitch Heave
IMU-007 0.25° RMS N/A
IMU-008 0.25° RMS 5cm or 5%
IMU-106 N/A 5cm or 5%
IMU-107 0.03° RMS N/A
IMU-108 0.03° RMS 5cm or 5%
IMU-108-30 (subsea) 0.03° RMS 5cm or 5%

Ideal for DP, AHC and Helidecks

Development over 15 years has produced a Motion Sensor suitable for applications from Active Heave Crane systems, Dynamic Positioning systems, Helideck Monitoring and other various Roll, Pitch and Heave motion applications.


MRU Helideck

Extended Kalman filter processing

High performance MEMS, rate gyros and accelerometers offering low noise and high accuracy as well as providing excellent vibration performance and reliability are used.

Gyroscopes, Accelerometers and Magnetometers are mounted in three axis component groups. The signals are processed in a Kalman filter inside the motion sensor to provide output value for acceleration, attitude and angle with limited influence from accelerations, noise and other inaccuracies.

Heave is computed from integration of the acceleration into a linear position. The integration is further processed and filtered for an accurate heave measurement during dynamic environment.

MRU Kalman filter

Quick and Easy device Configuration
The Configuration Software enables quick and easy device setup. The settings can be exported to act as an installation backup.

COM1 RS232 Bi-Directional
COM2 RS422 Bi-Directional
COM3 Data output and Aiding input
COM4 RS232 Aiding input only
Ethenet 10/100 Mbit. UDP and Modbus TCP/IP.
Analog output V or mA with remote converter
Output rate 1 to 200Hz
Baud rates 4800 to 115200bps

Motion sensor Communication

The SMC Motion Sensor transmits data over Ethernet UDP and Modbus TCP/IP and RS232/RS422 Serial communication.

Inputs for heading and velocity is available when required for aiding during vessel turns.

Output strings

The SMC string availabilities includes standard protocols used in the marine industry along Client Custom specific protocols that SMC has developed with our partners.

All available protocols, including among many others PSMCC, TSS1, EM3000 and PRDID, are user selectable from the SMC Configuration software. More information SMC IMU Manual

Output strings

Output strings

AHC integration

Unique to the SMC MRUs is the SMC Active heave compensation AHC encoder feedback.

Developed in conjunction with Bosch Rexroth drives the SMC AHC system accepts dynamic crane encoder position data, enabling continual calculation of the selected active heave measurement data to provide live motion compensation during critical marine crane operations.

Modbus TCP/IP communication implementation done with ABB enables seamless integration with the ABB ACS800 drives for new and Retrofit AHC applications.

Titanium Enclosure

SMC's product development and design philosophy is to produce technologically advanced, durable yet uncomplicated products.

The SMC MRUs are produced in Titanium suitable with its high strength, low density and corrosion resistance for the Marine environments the motion sensor works in.

IMU 108 Dimensions IMU 108 Dimensions

IMU 008 Dimensions IMU 008 Dimensions

MRU Ranges

The SMC Motion Reference Units have identical functionality and communications with different performance specifications. The IMU-10 series has higher performance sensing elements for greater accuracy.

Selection of which sensor is suitable for an application depends upon the Accuracy Required, international standards specified, how dynamic the operational environment will be as well as the projects budget.

Output strings

Option for IP66 and IP68

The Surface models of the SMC Motion Reference Units have an IP66 rating for outdoor water protection.

Submersible depth rated IP68 options are available rated for 30m respectively 1000m.


Each motion sensor is calibrated prior to delivery. The motion sensors are thoroughly tested in the SMC facilities before and during the calibration process. The calibration is performed in a 2-axis rate table with a temperature controlled chamber. The calibration process is fully automated and runs for three days with a controlled temperature environment over the full temperature range.

All motion sensors are calibrated individually and the readings from the accelerometers and angular rate gyroscopes are verified for alignment, linearity and temperature, to ensure they meet the performance specifications.

Technical specifications

Model features IMU-007 IMU-008 IMU-106 IMU-107 IMU-108
Roll/Pitch Yes Yes N/A Yes Yes
Accelerations Yes Yes N/A Yes Yes
Heave N/A Yes Yes N/A Yes
Performance Angle Accuracy static 0.2° RMS 0.2° RMS N/A 0.02° RMS 0.02° RMS
Angle Accuracy Dynamic
@ ±5° simultaneous roll and pitch
0.25° RMS 0.25° RMS N/A 0.03° RMS 0.03° RMS
Angle range Roll/Pitch ±30° ±30° ±30° ±30° ±30°
Heave Accuracy N/A 5cm or 5% 5cm or 5% N/A 5cm or 5%
Acceleration accuracy 0.05 m/s² RMS 0.05 m/s² RMS     N/A     0.01 m/s² RMS 0.01 m/s² RMS
Communication Ethernet 10/100 mbit. UDP and Modbus TCP/IP
Com1: RS232 Bi-Directional
Com2: RS422 Bi-Directional
Com3: RS232 Data Output and Aiding input
Com4: RS232 Aiding input only

Analog output V or mA with remote converter (optional)
Velocity input formats RMC, RMA, VTG, VBV, VHW; Heading input formats HDT, HDG
SMC IMU Configuration software included
User selectable Output Protocols
User selectable Output Rate 1-200hz
Physical Dimensions (W x H) Ø134 x 127mm excl connector
Weight ~2kg
Housing Material Titanium
Dimensions (W x D x H) 134 x 134 x 67mm excl connector
Weight ~0.5 kg
Housing Material Titanium
Environmental Temperature -20° to +55° Celsius
Storage Temperature -40° to +65° Celsius
MTBF (computed) 50 000 hours
IP66 as standard; IP68 30 meter depth rated optional
Mounting Orientation Horizontal as standard or Vertical as option (factory set)
Electrical Power requirements 12 - 30 VDC; 3 W
Standard Complies with the IEC 60945
Warranty & Support 2-year Limited Hardware & Software Warranty
Free Technical & Hardware support