Overview

Developments in deep water fields have led to an increasingly crowded operating environment, with multiple DP vessels required to work within acoustic interference range of each other. As DGPS suffers from scintillation or signal interference caused by sunspot activity, a demand has been created for DP drilling units to adopt the use of two independent acoustic systems that automatically weight the DP desk against DGPS. 

Sonardyne’s new Dual Independent Wideband LUSBL (Long and Ultra-Short BaseLine) system not only mitigates the problems of interference between vessels but it also allows multiple systems to be run on the same rig.  This is achievable through the availability of over 400 navigation channels, delivering true multi-operational capability in crowded field environments. The technology is also capable of providing greater immunity to noise, a ten fold improvement in measurement repeatability and faster position update rates when lowering structures onto the seabed.

The system is particularly suited to deep water applications as it combines the performance derived from Long Baseline (LBL) subsea positioning, where accuracy is virtually independent of water depth, with the operational convenience of Ultra Short Baseline (USBL) positioning. The accuracy of the LBL in deepwater is a result of the geometry of the seabed transponder array. Together with the range and bearing data from the USBL transceiver a very high level of redundant positioning information is achieved.

Combined, the LUSBL system outputs a continuous supply of precise and very repeatable position fixes to the vessel’s DP system. The high level of redundancy also ensures that in poor acoustic conditions in which deep water DP vessels often operate, many range measurements can be corrupted before the computed vessel position degrades.

Features & Benefits

Incorporates Sonardyne's latest Wideband Technology Sonardyne Wideband
Technology provides the highest accuracy and therefore the lowest risk for all subsea acoustic positioning tasks, regardless of water depth.

Easy and cost effective upgrade for existing Sonardyne LUSBL users; no need for vessel downtime

Dramatically improves the efficiency and safety of deep water, multi-vessel operations

Hundreds of operating channels allowing truly independent acoustic operations

Multiple operating modes; tone burst and wideband

Provides fast position updates when lowering structures onto the seabed

Offers greater immunity to noise and a ten fold improvement in measurement repeatability

Sonardyne Wideband

At the core of the LUSBL system is Sonardyne’s new Wideband-enabled acoustic transceiver and Navigation Processor.

Wideband acoustic signals are fundamentally more robust than analogue signals and are therefore better suited to real-time monitoring applications such as the acoustic telemetry of BOP and riser monitoring data. Crucially, because bandwidth is used more efficiently, more individual operating channels are available and this enables more users to work in the same environment without acoustic pollution. Wideband even offers practical cost savings such as extending transponder battery life.

Existing LUSBL users can take advantage of the new wideband LUSBL technology by installing it on existing hardware, thus enabling the vessel to remain in service. The use of familiar hardware and software on a proven topside platform eliminates the need for re-training and enables users to work with confidence from the outset. This low risk approach ensures operators can make a smooth transition to wideband whilst maintaining compatibility with their previous generation acoustic hardware.