UTEC-Sonardyne develop layered defence for GNSS-challenged pipelay projects 

A shallow-water pipelay project in the Middle East is set to demonstrate how to keep construction spreads working and accurately positioned during GNSS disruption.

UTEC, Acteon’s geo-services business, will use a hybrid acoustic-inertial positioning spread from Sonardyne, a Kraken Robotics company, to support pipelay barge and anchor-handling tug operations across two projects.

The work, spanning more than 150 km of pipeline installation, will take place in water depths of less than 50 m, where shallow-water spreads need dependable positioning for both the barge and support tugs, while reducing reliance on increasingly disrupted GNSS.

“The challenge is familiar to many offshore contractors working in regions where interference, denial and spoofing of GNSS signals – often the primary positioning reference for operators – are becoming operational realities,” explains Nadir Rahmatullah, Vice President Asia Pacific and Middle East at UTEC.

“Pipelay barges must be moved precisely as pipe is installed, while support tugs need reliable position data as they run and manage anchors around the construction spread. Any loss of confidence in positioning can affect efficiency, safety and schedule.”

Developed with Sonardyne, UTEC’s solution combines Fusion 2 LBL-INS survey software, Compatt 6+ LBL transponders and SPRINT-Nav navigation systems to provide resilient positioning for shallow-water construction operations.

SPRINT-Nav systems mounted on the pipelay barges and support tugs will provide continuous navigation using inertial and Doppler velocity log data.

When GNSS is available, operators can use it alongside the inertial solution.

Acoustic ranges to seabed-mounted Compatt 6+ transponders can then be used to reference the navigation solution to fixed points on the seabed, providing an independent positioning layer and reducing reliance on GNSS when signals become unreliable.

The same architecture also enables Fusion 2 to SLAM-calibrate a sparse Compatt 6+ seabed array as the spread advances along the pipelay route.

This removes the need for dedicated conventional array calibration work, reduces the number of transponders required and helps speed up operations.

The result is a flexible positioning architecture that supports day-to-day operations when GNSS is available, while providing an independent acoustic-inertial solution for higher-accuracy construction activities and resilience during periods of GNSS disruption.

“For UTEC, this will provide a practical way to deliver resilient positioning for shallow-water pipelay while reducing array size and limiting the amount of time spent on dedicated calibration,” adds Mujmal Essa, UTEC’s Country Manager.

The result will be a more efficient, lower-complexity positioning architecture for shallow-water pipelay in GNSS-challenged environments. It will also provide an additional tool for future offshore construction campaigns, where resilient, independent positioning is likely to become an increasingly important part of project planning.