The Motion Reference Unit (MRU) is a high-precision motion sensor designed to measure and compensate for vessel motion during offshore hydrographic, geophysical and geotechnical survey operations. The system provides accurate real-time measurements of vessel roll, pitch, heave, heading and heading rate, ensuring that survey data remain accurate despite vessel movement caused by waves, tides and sea conditions.

The Motion Reference Unit utilizes advanced inertial sensor technology and integrated processing algorithms to continuously monitor the vessel’s six degrees of freedom. Motion data are transmitted in real time to onboard navigation and acquisition systems, where dynamic motion compensation is applied to multibeam echo sounders, single beam echo sounders, side scan sonars, sub-bottom profilers, laser scanners and other marine survey sensors. This enables survey measurements to be accurately referenced to the true position of the survey equipment throughout the operation.

Designed for continuous offshore operation, the Motion Reference Unit provides high-frequency motion measurements with exceptional stability and low latency. The system interfaces seamlessly with GNSS positioning systems, gyrocompasses, inertial navigation systems (INS) and survey navigation software, providing synchronized motion and positioning data for real-time quality control, data acquisition and post-processing.

The Motion Reference Unit is widely used for hydrographic surveys, offshore geophysical investigations, marine geotechnical surveys, offshore construction support, dredging surveys, pipeline and cable route surveys, renewable energy developments and subsea inspection projects. By accurately compensating for vessel motion, the system significantly improves the accuracy of bathymetric measurements, seabed imagery and sensor positioning, ensuring the high-quality survey data required for offshore engineering and marine construction projects.