FAQs
Find the answer to your question here, or contact us at sales@norwegian-subsea.no.
Find the answer to your question here, or contact us at sales@norwegian-subsea.no.
A motion Reference Unit (MRU) is a device that measures motion in all six degrees of freedom (DoF): roll, pitch, yaw & surge, sway and heave. The six DoF positions, velocities and accelerations are measured by the MRU using high-end gyroscopes and accelerometers (and sometimes magnetometers) and processed by advanced sensor fusion algorithms.
When navigating the complexities of motion sensing and navigation systems, it is essential to understand the distinctions between devices and systems like Inertial Measurement Units (IMUs), Inclinometers, Roll & Pitch sensors, Vertical Reference Units (VRU), Attitude and Heading Reference Systems (AHRS), Motion Reference Units (MRUs), Gyrocompasses, and GNSS-Aided Inertial Navigation Systems (GNSS/INS). Each serves specific purposes and offers different levels of functionality, accuracy, and application scope.
Gyrocompass
The MRU (Motion Reference Unit) monitors vessel motions to evaluate risks related to sloshing and structural fatigue in cargo containment systems. It supports a condition-based inspection regime under DNV’s Alternative Survey Programme (ASP).
When navigating the complexities of motion sensing and navigation systems, it is essential to understand the distinctions between devices and systems like Inertial Measurement Units (IMUs), Inclinometers, Roll & Pitch sensors, Vertical Reference Units (VRU), Attitude and Heading Reference Systems (AHRS), Motion Reference Units (MRUs), Gyrocompasses, and GNSS-Aided Inertial Navigation Systems (GNSS/INS). Each serves specific purposes and offers different levels of functionality, accuracy, and application scope.
Inclinometer
The HS / commodity code for Norwegian Subsea MRUs is 9015.80.0000
A commodity code, also known as a Harmonized System (HS) code or tariff code, is a standardized numerical method used to classify traded products for customs purposes. It's crucial for calculating import duties, taxes, and identifying potential trade restrictions. These codes are globally recognized and consist of a specific number of digits, typically eight for exports and ten for imports.
When navigating the complexities of motion sensing and navigation systems, it is essential to understand the distinctions between devices and systems like Inertial Measurement Units (IMUs), Inclinometers, Roll & Pitch sensors, Vertical Reference Units (VRU), Attitude and Heading Reference Systems (AHRS), Motion Reference Units (MRUs), Gyrocompasses, and GNSS-Aided Inertial Navigation Systems (GNSS/INS). Each serves specific purposes and offers different levels of functionality, accuracy, and application scope.
When navigating the complexities of motion sensing and navigation systems, it is essential to understand the distinctions between devices and systems like Inertial Measurement Units (IMUs), Inclinometers, Roll & Pitch sensors, Vertical Reference Units (VRU), Attitude and Heading Reference Systems (AHRS), Motion Reference Units (MRUs), Gyrocompasses, and GNSS-Aided Inertial Navigation Systems (GNSS/INS). Each serves specific purposes and offers different levels of functionality, accuracy, and application scope.
Inertial Measurement Unit (IMU)
Yes. An MRU provides high-resolution measurements of roll angles, which makes it an effective tool for inclining tests (stability verification / "krengeprøve"). Unlike traditional pendulums, an MRU can deliver accurate data even when the test is carried out at sea under less-than-ideal conditions. By filtering out wave-induced motions and recording precise responses to applied test weights, the MRU improves both accuracy and efficiency of the inclining test.
A VRU is an advanced device that measures the attitude (roll and pitch) of an object using high-end accelerometers and gyroscopes, combined with advanced sensor fusion algorithms. VRUs provide very accurate roll and pitch measurements, even in dynamic environments.
In applications requiring real-time, high-accuracy roll and pitch data the VRU's precise Roll and Pitch data allows control systems to react effectively. For example, motion compensation of GNSS antenna for dynamic positioning (DP-systems), stabilizing fins on vessels or advanced Instrument compensation - Used in monitoring and control systems where only roll and pitch data is needed.
When navigating the complexities of motion sensing and navigation systems, it is essential to understand the distinctions between devices and systems like Inertial Measurement Units (IMUs), Inclinometers, Roll & Pitch sensors, Vertical Reference Units (VRU), Attitude and Heading Reference Systems (AHRS), Motion Reference Units (MRUs), Gyrocompasses, and GNSS-Aided Inertial Navigation Systems (GNSS/INS). Each serves specific purposes and offers different levels of functionality, accuracy, and application scope.
Roll & Pitch Sensor
When navigating the complexities of motion sensing and navigation systems, it is essential to understand the distinctions between devices and systems like Inertial Measurement Units (IMUs), Inclinometers, Roll & Pitch sensors, Vertical Reference Units (VRU), Attitude and Heading Reference Systems (AHRS), Motion Reference Units (MRUs), Gyrocompasses, and GNSS-Aided Inertial Navigation Systems (GNSS/INS). Each serves specific purposes and offers different levels of functionality, accuracy, and application scope.
GNSS-Aided Inertial Navigation System (GNSS/INS)
Yes, Norwegian Subsea Motion Reference Units (MRUs) are highly suitable for applications involving wave analysis. Our sensors provide precise measurements of motion in 6 Degrees of Freedom (6DoF), encompassing Roll, Pitch, Yaw, Surge, Sway, and crucially for wave analysis, Heave.
The high-accuracy Heave (vertical motion) data generated by our MRUs is fundamental for determining key wave characteristics such as wave height and period. Norwegian Subsea MRUs deliver a reliable Heave accuracy of 5.0 cm or 5.0%, enabling detailed analysis of sea states.
Improving the accuracy of subsea sensors fundamentally relies on selecting a high-performance unit designed specifically for the demanding underwater environment. At Norwegian Subsea, we achieve superior accuracy through a combination of state-of-the-art MEMS sensor technology, advanced sensor fusion algorithms, and robust hardware engineering, validated in real sea conditions.
Our algorithms are crucial for filtering noise and accurately calculating motion parameters like Roll, Pitch, Heave, Surge, Sway, and Yaw (6DoF), even under complex, irregular motion patterns typical of subsea operations. Furthermore, our sensors undergo rigorous testing and validation in real sea conditions, ensuring their performance specifications are met in the environments where they will be deployed.
Selecting the appropriate motion sensor for a subsea Remotely Operated Vehicle (ROV) is critical for precise navigation, positioning, and tool manipulation. Key comparison factors include accuracy (Roll, Pitch, Heave, Yaw), depth rating, physical size and weight, robustness, ease of integration with ROV control systems, reliability in harsh environments, and overall cost-effectiveness.
Norwegian Subsea offers the MRU Subsea, specifically engineered for demanding underwater applications like ROV operations. This unit features a robust, compact titanium housing depth-rated to 6000 meters, making it ideal for deep-water tasks. We provide different accuracy levels to meet specific operational needs, with Roll and Pitch accuracy options of ±0.05° (Series 3000), ±0.02° (Series 6000), or ±0.01° (Series 9000), and a standard Heave accuracy of 5.0 cm or 5.0%. Our sensors utilize advanced MEMS technology and sensor fusion algorithms, validated in real sea conditions.
A motion sensor, like the Motion Reference Units (MRUs) developed by Norwegian Subsea, functions by detecting and measuring movement. At their core, these sensors utilize state-of-the-art Micro-Electro-Mechanical Systems (MEMS) technology. MEMS accelerometers measure linear acceleration (changes in velocity along the Surge, Sway, and Heave axes), while MEMS gyroscopes measure angular velocity (rate of rotation around the Roll, Pitch, and Yaw axes).
To provide a comprehensive and accurate measurement of motion in all six degrees of freedom (6DoF) – Roll, Pitch, Yaw, Heave, Surge, and Sway – data from multiple MEMS sensors is intelligently combined. Norwegian Subsea employs advanced sensor fusion algorithms that process these raw sensor inputs, filtering out noise and compensating for external forces like gravity, to calculate precise orientation and movement data in real-time.