Sonardyne dynamic positioning fills in for GNSS disruptions

January 27, 2016  - By
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Bordelon Marine, providers of vessel services to operators in the Gulf of Mexico and around the world, has selected acoustically aided inertial navigation technology from Sonardyne Inc., Houston, for its new ultra-light intervention vessel (ULIV) Brandon Bordelon.

The dual Ranger 2 Pro DP-INS systems, the highest specification available, will be used to track remotely operated underwater vehicles (ROVs) during inspection, repair and maintenance activities and provide an independent position reference for the vessel’s Marine Technologies Class 2 dynamic positioning system.

Specialized vessels such as the Brandon Bordelon conventionally rely on GNSS and ultra-short baseline (USBL) acoustics  as their primary sources of dynamic positioning reference data.

However, a vessel’s station-keeping capability can be compromised in the event that the USBL is affected by thruster aeration or noise and the GNSS signal is simultaneously interrupted. The latter is particularly common around equatorial regions and during periods of high solar radiation.

Sonardyne’s Ranger 2 Pro DP-INS system addresses this operational vulnerability. It aids vessel positioning by exploiting the long term accuracy of Sonardyne’s Wideband 2 acoustic signal technology with high integrity, high update rate inertial measurements. The resulting navigation output has the ability to ride-through short-term acoustic disruptions and is completely independent from GNSS.

The Brandon Bordelon was delivered at the end of 2015 and is under a 60-day contract with Tidewater Subsea. Designed to support complex inspection, repair and maintenance operations, the vessel features a high-capacity deep-water crane, infrastructure for two work-class ROVs and a large, reconfigurable back-deck area.

In addition to the system’s deep water positioning performance and safety benefits, DP-INS has been proven to deliver valuable time and cost savings for vessel owners. It does not need a full seabed array of transponders to be installed and calibrated before subsea operations can commence.

For most subsea tasks, positioning specifications can be met with only one or two transponders deployed on the seabed. Additionally, as the system needs only occasional aiding from the acoustics, transponder battery life is substantially increased and the need to task an ROV to deploy and recover transponders for servicing is reduced.

The equipment supplied to Bordelon Marine included Sonardyne’s ship-mounted inertial navigation sensor and two HPT 7000 acoustic transceivers. The HPTs have been installed on the Brandon Bordelon through-hull deployment poles and are optimised for tracking and dynamic positioning in ultra-deep water.

Wes Bordelon, President/CEO Bordelon Marine said, “Equipping the Brandon Bordelon with Sonardyne’s Ranger 2 DP-INS, reflects our commitment to providing high-tech, high-spec equipment on our fit-for-purpose Stingray vessels and ensuring our fleet is safe, efficient and cost-effective.

“Ranger 2 DP-INS is a mature, field proven technology that addresses operators’ need for a robust, independent DP reference that provides an update rate and accuracy on par with GNSS,” said Ralph Gall, Technical Sales Manager at Sonardyne in Houston. He added, “The Brandon Bordelon joins a significant fleet of vessels which depend upon our acoustically-aided inertial technology for safer and more efficient dynamic positioning operations.”

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