Underwater Positioning

At Imenco Nautronix, we provide a range of advanced subsea acoustic Underwater Positioning systems, including vessel based and seabed systems. Using the latest generation of signalling technology, the systems employ a broadcast technique providing true multi-user, accurate and reliable positioning in all water depths with no acoustic interference, providing clients with accurate positioning and substantial cost savings.

Our Subsea Underwater Positioning and navigation systems use three different principles for measurements and calculations:

Long baseline (LBL)
LBL systems consist of an array of transponders located on the seabed, with distances being acoustically measured from the calibrated array to any mobile objects requiring to be positioned.

Short baseline (SBL)
SBL systems are vessel based with an array of, typically, 4 or 6 hydrophones on the hull of the vessel. Distances can be measured between the hydrophones and the objects being positioned subsea to determine a position relative to the vessel.

Ultra short baseline (USBL)
USBL systems are similar to SBL systems but use a single transducer on the vessel. With this method there is often a difference with the timing of the acoustic signal, however with the use of multiple elements, determining the angle from which the signal came from has never been easier.

Our NASNet® range of seabed stations and receivers can be easily installed to meet any subsea positioning requirement with bespoke applications designed for specific operations:

• NASNet® DPR takes the NASNet® concept to provide the ultimate tailored solution for vessel dynamic
• positioning reference (DPR)
• NASNet® FPR further enhances the functionality of NASNet® DPR by adding acoustic monitoring and control functions for fixed positioning reference (FPR) tasks such as FPSO positioning, riser and mooring monitoring.

Subsea data transfer and control of seabed assets is available in our NASCoM product range.