Xsens: Heave is Here - MRUs for Real-Time Vertical Motion Monitoring
With its latest firmware update, our partner Xsens has enhanced its Avior and Sirius inertial sensor lines by adding real-time vertical-motion tracking — known as Heave. This transforms the Avior and Sirius modules into fully-fledged Motion Reference Units (MRUs), offering not only roll, pitch (and yaw/heading) data, but also accurate vertical displacement information.
Heave allows marine systems, from offshore cranes and drilling rigs to docking platforms, to maintain stability and precision even in changing wave condition. Within about 40 seconds, the Xsens heave algorithm adapts to new sea states and continues delivering accurate, real-time motion data.
Xsens Heave Highlights
- Real-Time Vertical Displacement - Immediate heave data for active heave compensation systems — from offshore cranes to docking and drilling platforms
- Centimetre-level accuracy - < 5 cm up to 29 seconds, <6 cm up to 40 seconds
- Instant integration - get heave output with a simple firmware update + one checkbox in MT Manager or using Xsens SDK
- OEM or Rugged - Available in 2 form factors: OEM (Xsens Avior MRU) and Rugged (Xsens Sirius MRU)
The Heave output is computed directly on the sensor — no external post-processing needed. Xsens’ algorithm uses a double integration of the accelerometer data to derive vertical displacement, combined with orientation data (gyroscope + optionally magnetometer) to correctly isolate “true vertical” acceleration even when the vessel is rolling or pitching. Because raw double-integration typically suffers from drift over time, Xsens developed an adaptive, phase-correction filter. This “math-magic” enables the computed heave to stay aligned with real-world motion, avoiding drift and ensuring real-time accuracy.
Main Applications
Heave is fundamental for multiple surface applications where you need to account for wave motion and Active Heave Compensation is required.
- Offshore drilling & crane operations - Compensate vertical vessel motion to keep tools and payloads steady.
- Docking & dynamic positioning - Maintain safe, precise alignment during surface operations.
- Marine robotics (ROVs, AUVs, ASVs)- Improved control and navigation near the surface.
- Buoys & surface monitoring - Track and record wave-induced displacement.
- Survey & mapping platforms - Remove vertical motion noise for cleaner data.
If you would like to learn more about the new Heave feature, please contact your SE Sales Representative or write to us at vertrieb@spezial.com.