Components and processing

The SMC marine motion sensors use solid state MEMS rate gyros that offer low noise and high accuracy as well as providing excellent vibration performance and long life reliability.

Three separate axial measurement component groups made of Gyroscopes, Accelerometers and Magnetometers are mounted in three axis for X, Y and Z measurements. The signal from the gyroscopes are combined with the signal from the accelerometers and magnetometers and 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 a double integration of the acceleration into a linear position. The integration is further processed and filtered for an accurate heave measurement during dynamic environment.


Communication

As a standard all SMC marine motion sensors have 1 x RS232 and 1 x RS422 communication ports enabling the selection of Industry standard and bespoke output protocols. For aiding and data inputs 2 x RS232 serial ports are available. Ethernet connection is available as factory option, UDP output. Update Rates of 1 to 100Hz and 9600 to 115200 baud rates for selected protocols.


Aiding from Compass and GPS

SMC motion sensors can use inputs for aiding from standard industry GPS or Compass systems already installed on a vessel to improve measurement results during vessel turns. This is particularly useful during hydrographic surveying where performance can be maintained during quick turns.


AHC Crane encoder feedback

Unique to SMC motion sensor is our SMC Active heave compensation AHC encoder feedback option developed in conjunction with Bosch Rexroth drives but available for all users. The SMC AHC system accepts dynamic crane encoder position data for dynamic active heave compensation in marine crane applications.


Motion Sensor Configuration software

The SMC marine motion sensor configuration software has been developed with ease of use and the different industry users in mind. An uncluttered display with separate control pages, the SMC motion sensor configuration tools enable any user to understand and carry out a motion sensor installation with the minimal of fuss.


Motion Sensor Protocols

Knowing that the motion sensors are used in multiple fields with multiple separate equipment’s and systems as many user selectable protocols and standard strings have been installed as default in the motion sensors which makes the motion sensor compatible with most applications on the market.


Calibration of Marine Motion Sensor

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.