Kongsberg Seatex, Kongsberg Maritime’s position reference specialist division, is launching two new Motion Reference Units (MRU). Both products have been designed specifically for survey and crane operations, and outside installations, such as heli-deck monitoring.
The new MRU 3 is designed for roll, pitch and heave compensation applications, including real-time heave compensation of echo sounders during survey operations and active heave compensation of offshore cranes. It provides heave measurements to meet IHO standards, ensuring that echo sounder data is highly accurate pre- and post-processing, while offshore crane safety and efficiency can be also be improved. The MRU 3 achieves reliability by using solid state sensors with no rotational or mechanical parts.
A second new model, the MRU E, is specially designed for use in marine applications requiring an extended temperature range. It can operate at ambient temperatures from -25 to +70°C and can be installed on open decks, inside cabinets or on bulkheads. Typical applications include direct mounting under the heli-deck center to measure 3-axes linear accelerations together with roll, pitch and heave. Because of the extended temperature range of the MRU E, no additional enclosure or cabinet is required, and the system meets Heli-deck Certification Agency (HCA) requirements to measure heli-deck acceleration and calculate Motion Severity Index (MSI).
Both new MRUs accept input of external speed and heading information on separate serial lines or Ethernet for improved accuracy in heave, roll and pitch during turns and accelerations. For time synchronization, the MRU accepts 1-second time pulse (1PPS) input on a TTL line (XIN) or as RS-232 or 422 signal. The MRU 3 and MRU E also make data available through an Ethernet interface, enabling easy distribution to multiple users on board the vessel. Output protocols for commonly used survey equipment are available on two individually configurable serial lines and Ethernet/UDP, with communication protocols selectable in the Windows based MRU configuration software.