RANGER 2 USBL ON TRACK AROUND THE WORLD
From navigating deepwater exploration ROVs, to helping dive support vessels maintain a reliable position, Sonardyne’s Ranger 2 USBL acoustic technology is proven to reduce risk, save time and extend operational capability. Sonardyne takes a closer look at how three very different organisations are benefiting from the investment they have made in this technology.
Going deep with MBARI Located in Moss Landing, California, the Monterey Bay Aquarium Research Institute (MBARI) is recognised as a world centre for advanced research and education in ocean science and technology. To support its work, it has at its disposal a wide range of marine technology and assets including; research vessels, deep rated ROVs, several AUVs and a large inventory of scientific instruments.
Over the past 15 years, Sonardyne’s Ultra-Short Baseline (USBL) technology has supported many of MBARI’s expeditions off the California coast where water depths rapidly reach beyond 13,000 feet. However, it was noted that on occasions, multi-path signals reflecting off their twin hulled research vessel, Western Flyer and noise from ROV thrusters, were interfering with transponder signals coming from great depths.
“Challenging conditions like these are exactly why we developed 6G – our sixth generation acoustic positioning platform. 6G systems like Ranger 2 use Wideband 2 digital signal architecture to provide robust underwater target tracking, greater precision and fast position updates in all scenarios, deep or shallow and on all types of vessel. We were confident that by upgrading the Western Flyer to the latest 6G standard, MBARI’s deep water vehicle operations would be faster, more accurate and more efficient”.
As part of the upgrade, the Western Flyer was fitted with Sonardyne’s deep water optimised HPT 7000 USBL transceiver. Co-located with it on the vessel’s deployment pole was Lodestar, Sonardyne’s premium grade motion sensor – a configuration referred to as Optimised USBL.
This integration achieves a tightly compensated solution and allows the positioning accuracy obtainable from Ranger 2 to be maximised.
For MBARI, proof of Ranger 2’s capabilities came during a recent expedition that ran earlier this year to study deep sea hydrothermal vents recently discovered in the Gulf of California.
Tethered to the Western Flyer, their ROV Doc Ricketts repeatedly dived down 12,500 feet (3,800 metres) to the seafloor and flew around the Pescadero Basin vent field, collecting video and samples for analysis. Despite the challenging conditions created by the vents spewing out super-heated seawater and suspended solids, the positioning repeatability of Ranger 2 was shown to be just a few metres, performance that enabled MBARI’s ROV pilots to save time by flying directly to points of interest.
Commenting on the success of the project, Knute Brekke, Chief ROV Pilot for MBARI said, “During the entire length of the project in the Pescadero Basin, our acoustic tracking enabled us to return to scientific sites of interest repeatedly with three-metre accuracy, well within visual range of the ROV cameras using Sonardyne’s Ranger 2 USBL system.” He went on to say, “Even though we are a relatively small organisation, we appreciate the support and advice that we have received from Sonardyne on the systems we have purchased to date, and the projects we have used them for.”
Upgrading CCC’s fleet
Deep underwater target tracking of ROVs is just one of the many applications for Ranger 2. It’s equally effective and capable as an acoustic reference sensor for dynamic positioning systems and is installed on a global fleet of vessels. One such fleet is operated by CCC (Underwater Engineering) S.A.L, leading providers of offshore construction and subsea services in the Middle East and India.
Four multi-purpose vessels make up CCC’s fleet, including two new 65 metre vessels rated for Class 2 operations. All are fitted with DP systems from GE, with their two 90 metre Dive Support Vessels, the CCC Pioneer and the new build Said Alethia, equipped with dual Ranger 2 Pro systems – the highest specification available. This capability has allowed CCC to utilise their vessels on survey projects where maintaining a reliable position is a critical operational requirement.
For all of its Ranger 2 installations, CCC additionally specified Sonardyne’s Optimised USBL configuration. Here, Sonardyne’s premium grade Attitude and Heading Reference System (AHRS) Lodestar is interfaced directly with the Ranger 2 acoustic transceiver allowing raw range, bearing and attitude data to be simultaneously processed. This integration achieves a tightly compensated solution and allows users to meet the positioning specifications of a wide range of subsea construction and survey projects.
Captain Derrick Green, Marine Operations Manager at CCC said, “Our vessel fleet is geared up to support all manner of complex underwater projects. Ranger 2 meets our needs in every respect, offering stable and precise positioning for DP, reliable tracking in any water depth and hardware that is easy for our crews to set up and use. We could not be happier with the results we are seeing back from the field.”
Horizon saves time with GyroUSBL
Setting up a USBL system can be time consuming, often requiring several hours of calibration checks to determine the alignment of the ship’s motion sensors to the acoustic transceiver prior to use. That’s why Sonardyne developed GyroUSBL, a transceiver that can be made operationally ready in 60 minutes from out of the box to survey use. Following its introduction, UAE-based Horizon Geosciences, were quick to realise its potential, ordering Ranger 2 systems configured with GyroUSBL for their operations. Now, after taking delivery of an additional two systems to complement those already in their inventory, Horizon is the largest user of the technology in the region.
The secret of GyroUSBL’s success comes from the integration of Sonardyne’s sixth generation acoustic transceiver technology and high grade inertial navigation sensor, Lodestar, in the same mechanical assembly. This unique combination removes many sources of USBL error including lever arm offsets, pole bending and ship flexing. It has also been proven to exceed accuracy and precision expectations, even when deployed on a temporary pole arrangement over the side of a vessel.
“We provide precise positioning for numerous activities offshore and often have to mobilise personnel and positioning equipment at short notice. GyroUSBL fits in perfectly with the unpredictable nature of our operations without compromising standards,” said Lance Hanson, Survey Projects Director at Horizon Geosciences. He went on to say, “We witnessed performance and operational gains soon after we began using GyroUSBL, so we decided to expand our deployment of the technology.”
“Ranger 2 meets our needs in every respect, offering stable and precise positioning for DP, reliable tracking in any water depth and hardware that is easy for our crews to set up and use.”