Straight out of the box navigational enhancement for offshore out of straightness surveys
Fugro
Fugro are already delivering safer, faster and more sustainable offshore operations – as you may have read in our previous case study about the Mini-Ranger 2 USBL system being used to support ROV operations from a USV. Working with us, Fugro are continuing their pioneering remote operations with their fleet of uncrewed surface vessels (USVs) deploying remotely operated vehicles (ROVs) – changing the game for offshore infrastructure surveys. Read on to see how our SPRINT-Nav Mini is being used to enhance multibeam echosounder (MBES) on Fugro’s remote operations, providing incredible results.
The challenge
Out of straightness (OOS) surveys are used for acquiring information about the vertical and horizontal configuration of offshore pipelines. They provide operators with information on the presence or otherwise of buckles and bending in a pipeline, which may be engineered or not, and require monitoring during the operational life of the pipeline or flowline asset.
Fugro have been conducting OOS surveys on pipelines for major energy companies in Australia for many years. These surveys were conducted using a Norbit WBMS Narrow Multibeam echo sounder mounted on a Fugro inspection class ROV deployed from Fugro’s 12m Blue Essence® USVs, Maali and Kwilena.
ROV missions along pipelines can be erratic and unreliable due to the distance between the transceiver (USV) and transponder (ROV) when using just USBL positioning. For Fugro’s OOS survey customers, highly accurate data is essential. This has led to their requirement for the highest accuracy navigation and imaging available to the small ROV.
Fugro set us the challenge to provide a navigation solution that would enable the customer requirements of high-quality data using a small ROV. We worked with Fugro to trial SPRINT-Nav Mini and demonstrate the capabilities of the system.
The solution
SPRINT-Nav Mini is the world’s smallest hybrid navigator, combining INS, DVL, AHRS and a pressure sensor in one factory calibrated unit. SPRINT-Nav Mini’s true north seeking gyrocompass means that it delivers reliable surface and subsea navigation. Adding this navigation capability to any marine robotic system allows users more control and turns their vehicles into far more accurate inspection and survey platforms.
With everything you need for navigation packed into a single low Size, Weight and Power (SWaP) package, SPRINT-Nav Mini is simple to integrate into any marine vehicle along with other payload sensors, like Fugro’s MBES. Its impressive precision of 0.05% of distance travelled accuracy on a typical survey alongside our revised heading, pitch and roll specification means that advanced mapping is now possible on smaller platforms deployed from USVs.
“SPRINT-Nav Mini is becoming increasingly vital for geophysical survey operations where SWaP is critical. Users need accurate and high output rate navigation streams for real-time compensation of imaging sensors.” Says John Houlder, INS Product Manager, Sonardyne, “SPRINT-Nav Mini provides robust real-time results that are improved even further once post-processed in our Janus software.”
After demonstrating SPRINT-Nav Mini’s capabilities, Fugro purchased the system and have been deploying it on their inspection ROV, which in turn is deployed from the Blue Essence® USV. With the Fugro team’s input we have been able to revise our specification for SPRINT-Nav Mini, improving its suitability for use with MBES on geophysical survey. These revisions include:
Pitch and Roll: 0.1 to 0.02° RMS
Heading: 0.15 to 0.1° RMS
“Deploying robotic platforms over-the-horizon to deliver important information to clients in the way that Fugro are doing means that they have to trust not just their platforms, but the payloads onboard.” said Aidan Thorn, Business Development Manager, Marine Robotics at Sonardyne, “Having SPRINT-Nav Mini providing navigation enables this trust as well as the excellent MBES data that we see here. Fugro have chosen both our Mini Ranger 2 for positioning and are now benefiting from SPRINT-Nav Mini for navigation, underlining our value to pioneering marine robotic operations.”
Find out more about SPRINT-Nav Mini here
The results
Fugro utilise SPRINT-Nav Mini data within the ROV command and control software, Starfix® navigation, including their Camblock Vision based augmented reality system, and for processing MBES data. In the case of MBES processing, they are also conducting pipeline OOS surveys to a maximum depth of 200 metres.
The images below show some example data Fugro has gathered with MBES positioned using SPRINT-Nav Mini and post processed with our Janus software. Janus is our quality control and INS post processing software. It allows quick and easy data editing, post-processing and data export. Find out more about Janus here
In this image (above), pipeline bending during operational conditions is measured showing areas of freespan (red) and areas where the flowline is supported (yellow) in Fugro’s Sense Pipelines application. 
The second image shows pipeline clamping mattresses providing on bottom stability to the flowline to prevent “walking” phenomenon over the design life of the flowline.
We were attracted to the SPRINT Nav Mini form factor and integrated (factory calibrated) DVL. The ability of the DVL to achieve bottom track from the surface for most of our deployments in water depths less than 200 metres also brings efficiencies to our operations. The performance we’ve seen from SPRINT Nav Mini after Janus processing for MBES surveys is on a par with larger work class ROV deployed systems Fugro uses.
Matt Lussu. Principal Hydrographic Surveyor. Fugro
If your offshore operations are also reliant on fast, efficient and accurate data to keep your business competitive in an ever-changing marketplace, take a look at our full range of navigational products here.
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