The evolution of technology is often driven by a simple but powerful idea: there must be an easier way. Twenty years ago, our Ranger Ultra-Short BaseLine (USBL) positioning system was developed to do just that.

Designed to make high-performance acoustic positioning easier to use, Ranger has become the trusted reference across science, offshore energy, defence and autonomous operations worldwide.

A history of positioning at Sonardyne

Since its very beginnings in the 1970s, Sonardyne has been the leader in underwater positioning technology. Driven by the exacting demands of the offshore industry, we set a global industry standard for Long BaseLine (LBL) technology for subsea construction and survey.

By the 1990s, we had also introduced an Ultra-Short Baseline (USBL) system widely regarded as the industry benchmark for survey-grade performance. It could handle complex tasks such as deep-water metrology, construction support, the positioning of underwater vehicles and structures and, in L/USBL mode, a DP reference for deep water drilling units.

It was our first Windows-based software with extensive features and configuration options that met the highest demands of the most experienced surveys. But for many users, this often made it overly complex for everyday operations.

By the early 2000s, we also had our Scout, a cost-effective entry-level HF USBL system, ideal for tracking targets in shallow water. But users still found the interface overly complex.

A demand for easier to operate performance

There was a need for an intermediate system dedicated to USBL positioning, with the performance of our survey-grade systems, but that that was easier to use.

The turning point didn’t come from a roadmap or a market analysis. It came from a software engineer, who saw the problem firsthand while working offshore supporting development of Sonardyne’s dual redundant LUSBL DP system.

“If you sit on the bridge of a Drillship with a DP operator, you realise that they have to be familiar with many different systems made by different vendors and they need these systems to be intuitive,” explains James Allen, who now leads our custom projects team.

The dual redundant LUSBL DP system was built on the concept of being simple to use but robust in its operation. By adopting this architecture, building on the wider team’s existing work, he created a concept for a simple, PC-based USBL system that anyone could use, without needing a training course.

“Complexity was stripped away – right down to a single, dedicated control to start and stop tracking,” explains Duncan Rigg, Business Development Manager, Vessel Systems. “The focus shifted from what the system could do to how easily operators could get reliable results. When the prototype was shown at an internal sales meeting in 2006, the impact was immediate. This wasn’t an incremental improvement – it was a better way of delivering USBL performance.”

The Ranger USBL development project was approved that day. Later that year, Ranger was launched, setting a new direction for survey-grade positioning: power, delivered with simplicity.

The birth of Ranger: power meets simplicity

Ranger was engineered to provide survey-grade USBL performance in an easier-to-operate package. It used the same familiar software engine as our other systems, which made it an easy transition for existing users, but its streamlined interface removed the operational complexity.

“Early adopters, particularly in the oceanographic research community, quickly recognised its value,” explains Kim Swords, Technical Sales Manager, Sonardyne Inc. “Monterey Bay Aquarium Research Institute (MBARI), a long-time partner since installing our first USBL on its original vessel, the RV Point Lobos, in the 1990s, was a key user.

“They embraced our Ranger technology, later upgrading the R/V Western Flyer to Ranger 2. Even their latest vessel, the R/V David Packard, which joined their fleet in March 2025, also has Ranger 2.”

The system’s appeal was broad, finding a home across scientific, offshore energy and naval sectors. Early adopters included:

• Ocean science: Research vessels like the RV Neil Armstrong, operated by Woods Hole Oceanographic Institution, were fitted with Ranger for its precision and range, facilitating remotely operated vehicle (ROV) positioning, seabed coring and towed body navigation.
• University research: Institutions like the University of New South Wales used it for precise geo-location of sediment samples and during underwater video transects.
• Offshore energy: Construction companies integrated Ranger for critical subsea positioning and vessel operations.
• Autonomous operations: Ranger’s ability to integrate tracking and communications was vital for enabling complex missions with autonomous underwater vehicles (AUVs).
• Dynamic positioning (DP): Another early and significant use case was as a DP reference, interfaced with DP systems, for station keeping over subsea assets during ROV operations, while drilling or during installation support.

The road to Ranger 2

As Sonardyne further expanded its capabilities, these led to further advances for Ranger – and the introduction of Ranger 2.

A significant advance was made by our Marksman LUSBL system. Marksman introduced a new USBL system to which the ability to combine LBL and USBL positioning with inertial measurements was added. This capability made DP-INS possible – providing the independent reference system with equivalent performance to GNSS that vessels like drillships or rigs needed for maintaining their position whilst on dynamic positioning,.

But, critical to the next development of Ranger, Marksman introduced the Navigation Sensor Hub (NSH); a single, integrated topside processor providing microsecond timing and control of serial communications, and timing triggers as well as power control to devices.

Around the same time, we had also launched its 6G hardware and Wideband 2 acoustic signal technology.

Launched in 2010, Ranger 2 built directly on Marksman’s operational and architectural principles. It also leveraged 6G and Wideband acoustic signals, initially working across both tone- and Wideband-based, supporting customers and operations regardless of which technology they had.

Around the same time, Gyro USBL was released. This integrated the USBL transceiver with internal attitude and heading sensors, eliminating alignment and lever-arm errors. This meant calibration-free, high-precision survey-grade USBL set up, while also enhancing precision and accuracy.

Ranger 2 milestones

• Spring 2011 – Air France AF447 recovery: A Ranger 2 system played an integral role in recovering the flight data recorders from Air France flight AF447. Deployed aboard the cable ship Ile de Sein, it precisely monitored the ROV as it moved through the debris field in 3,900 m of water
• 2012 – Amelia Earhart search: Phoenix International and Bluefin Robotics used Ranger 2 with Gyro USBL to track ROVs and AUVs surveying for Amelia Earhart’s crash site near Nikumaroro Island. The system achieved reliable tracking of an AUV over 1,000 m away in shallow water.
• 2012/13 – Deep research tracking: WHOI used Ranger 2 to track the ROV Jason to the seabed at 4,700 m in the Pacific Ocean off Hawaii.
• 2015 – Pioneering Spirit integration: The world’s largest construction vessel, Allseas’ Pioneering Spirit, chose Ranger 2 as its primary acoustic DP reference system.
• 2015 – Slant range record: During trials in the Bay of Biscay, Odyssey Marine Exploration used a Ranger 2 GyroiUSBL system to track a deep-tow platform at a record-breaking slant range of 7,500 m. An “inverted” USBL set up was used, with the Gyro USBL mounted on the deep-tow platform. Only the lack of a longer tow cable prevented greater ranges being achieved.

Adoption and autonomous operations

Very quickly, Ranger 2 and Gyro USBL was adopted across offshore energy, scientific research and construction. Early projects included offshore wind sites such as Blyth, Horns Rev 1, and Thornton Bank. It became a trusted acoustic reference for large vessels, including the world’s highest capacity heavy lift vessel, Allseas’ Pioneering Spirit.

Ranger 2 also played a strong role in the development and demonstration of the capabilities of autonomous or uncrewed surface vessels (USVs) by enabling their expanded capabilities.

“This included, in 2018, the ARISE project, where we used Ranger 2 to track a Saab Seaeye Falcon ROV operated remotely from an L3Harris C-Worker 7 USV, demonstrating its role in cutting-edge remote intervention,” explains Aidan Thorn, Business Development Manager, Marine Robotics.

“Ranger 2 combined high-accuracy positioning with high-speed, two-way acoustic telemetry, transforming USBL from a reliable survey tool into a multi-role, gateway positioning and communications platform,” adds Rigg. “Capabilities included tracking up to 99 targets, accuracy to 0.04% of slant range, operations to 11,000 m depth, and support for multi-robot and dynamic positioning (DP) applications.”

• 2016 – Tectonic plate monitoring: Researchers in the Mediterranean used Ranger 2 and 6G LBL to position the seafloor at a depth of 2,400 m with centimetre-level precision. The acoustic range measurement precision was estimated at 5 mm.
• 2018 – 11 km tracking: During trials off California and Tenerife, the lower medium frequency (LMF) version of Ranger 2 reliably maintained tracking of targets at slant ranges beyond 11 km. These trials achieved a slant range error of only 0.14% (1 DRMS) at depths of 4,400 m, meaning position fixes were within 15.4 m even at 11,000 m away.
• 2019 – Mission Goldeneye: Researchers aboard the RRS James Cook used Ranger 2 to track a modified Gavia AUV at the decommissioned Goldeneye field to study carbon capture and storage (CCS) leaks.
• 2025 – International Ocean Drilling Programme (IODP): Scientific drilling vessel, Chikyu, achieves a world record for the deepest offshore drilling operation. Marksman was used to provide a DP reference throughout the drilling program in a water depth of 7,608.5 m.

The Ranger 2 USBL family: a solution for every user

By 2018, Ranger 2 was a single, scalable family – Micro, Mini, and Standard – unified by 6G hardware and Wideband standard.

This included Wideband 3, completing the evolution by embedding sensor telemetry into navigation signals, enabling efficient, high-precision positioning across the full range of subsea operations.

From a simple idea in 2006 to a complete family of solutions today, the Ranger legacy is one of listening to our customers and engineering technology that makes their lives easier.

Whether you need the grab-and-go portability of Micro-Ranger 2, the versatile nearshore power of Mini-Ranger 2 or the full deep-ocean capability of Ranger 2, the core principles today remain the same: simplicity, compatibility and scalable, trusted performance.

It’s a complete ecosystem ready for multi-target, multi-robot and fully autonomous operations, from the coast to the deepest frontier.