Motion Reference Unit

The MRU uses 3 axis accelerometers, 3 axis gyros and 3 axis magnetic sensors integrated with dual embedded micro-processors to produce accurate pitch, roll and heave information in an industry standard format. The MRU 333GI adds an internal GPS receiver and integrates GPS position with heading and speed to correct acceleration for heading changes. This improves settling following turns and removes errors in heave due to heading changes. A built in true north world magnetic map is used to produce a true north output. A “learning” software routine adjusts the MRU series to the boat characteristics to further improve overall accuracy.

Pitch – Roll – Heave
  • Single Beam Surveying
  • Multi-beam Surveying
  • Motion Stabilization
  • USBL Navigation
  • Hull Mounted ADCP
Pitch – Roll – Heave
  • GPS Aided—Course Changes
  • Single Beam Surveying
  • Multi-beam Surveying
  • USBL Navigation
  • ADCP Stabilization
Pitch – Roll – Heave
  • ROV Attitude
  • Diver Tracking Systems
  • Under-water Construction
  • Dredging Operations
  • Directional Drilling

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Description

The MRU uses 3 axis accelerometers, 3 axis gyros and 3 axis magnetic sensors for pitch, roll, and heave calibration. SDI’s (M)onion (R)eference (U)nit integrates dual embedded micro-processors to produce information in an industry standard format. The MRU 333GI adds an internal GPS receiver and integrates GPS position with heading and speed to correct acceleration for heading changes. Add improvement to settling after turns. Remove errors in heave due to heading changes. A built-in true north world magnetic map produces a true north output for optimal accuracy. A “learning” software routine adjusts the MRU series to the boat characteristics to further improve overall accuracy. The MRU is a great addition to your BSS+ and Bathycase when trying to increase accuracy to your pitch roll heave calibration.

Options

Pitch - Roll - Heave
  • Single Beam Surveying
  • Multi-beam Surveying
  • Motion Stabilization
  • USBL Navigation
  • Hull Mounted ADCP
Pitch - Roll - Heave
  • GPS Aided—Course Changes
  • Single Beam Surveying
  • Multi-beam Surveying
  • USBL Navigation
  • ADCP Stabilization
Pitch - Roll - Heave
  • ROV Attitude
  • Diver Tracking Systems
  • Under-water Construction
  • Dredging Operations
  • Directional Drilling

MRU Mechanical Specs

Material T6061 T6 Anodized Marine AL
Diameter 7.6cm (3in.)
Length 25.5cm (10in.)
Weight 1.1kg. (2.5lbs.)
Depth Rating (MRU333) 450m (1500ft.) or 1800m (6000ft.) optional

MRU Performance Specs

PitchRollHeading ResolutionDegrees AccuracyDegreesStatic RangeDegrees RepeatabilityDegrees
Pitch 0.02 0.2 +/-180 0.05
Roll 0.02 0.2 +/-180 0.05
Heading 0.10 0.3 360 0.10
Update Rate All Parameters 30 per second
Heave HeaveAmplitudeAccuracy MaximumUpdate RateSamples/Sec. RangeMeters Drift(T=10s)
MRU333 5cm 0-10 sec.+/-5% 30 5 <5cm(uncorrected)

Worldwide Distributors

Specialty Devices Inc.
2905 Capital St.
Wylie Texas 75098

972-429-7240 office

European Distributors

Aquifer Advies bv
Ben ten Toom
Dr. Langeveldplein 6
3361 HE Sliedrecht
0184 – 413147
06 – 24745947

About SDI

For over 30 years, SDI has designed and manufactured bathymetric and sub-bottom survey systems, sediment coring devices, and other specialized survey systems. SDI also provides geospatial, geophysical, hydrographic, sub-bottom, and sediment sampling services.