Australian vessel operator Tenggara Explorer wanted to see if there was another way. Could DP-level control for ROV-follow capability be achieved on a non-DP class workboat?

Together, maritime autonomy and AI specialist Greenroom Robotics, ourselves and Unique Group equipped the 34 m-long Tenggara Explorer multipurpose vessel with integrated DP-level control and USBL for ROV-follow capability for their client’s medium-size inspection-class ROVs (with the capability to attach the Sonardyne transponder to any unit).

The Solution

The core of the solution was the integration of two key systems, Greenroom Robotics’ autonomy software, GAMA and our Mini-Ranger 2 USBL system.

Greenroom Robotics’ GAMA

GAMA is advanced autonomy software that is hardware agnostic and can be retrofitted to existing vessels to enable remote, hybrid and autonomous control.

GAMA’s Dynamic Predictive Control (DP-C) independently controls thrusters, propellers and rudders using sensor feedback and control algorithms to counter wind, waves and current. This provides DP-level control to smaller more agile workboats, like Tenggara Explorer enabling precision positioning.

As a result, survey teams on smaller vessels can execute complex manoeuvres and survey patterns with high precision, at day rates around 80% less than a DP-class vessel, and with lower risk than manual precision control.

Mini-Ranger 2 USBL

Our industry-leading Mini-Ranger 2 USBL system is engineered for high-performance tracking of underwater targets from surface vessels in shallow waters and coastal environments, providing stable and reliable tracking, even in challenging sea conditions.

It’s lightweight and portable, making it easy to integrate into smaller vessels, even including smaller uncrewed surface vessels (USVs). Installed on the Tenggara Explorer, Mini-Ranger 2 provides the high-accuracy positioning data required to track the ROV during inspection tasks and survey work.

Crucial to successfully integrating these systems onto the Tenggara Explorer was:

• Robust platform integration: direct interfacing with helm, propulsion and auxiliary thruster systems to enable smooth, coordinated actuation.
• Sensor fusion and target tracking: combining GPS, IMU, wind, and USBL subsea positioning data to maintain stable lock on both fixed coordinates and moving underwater assets.

Unique Groups’ team was the crucial integration partner, ensuring the vessel’s complex systems worked together, enabling its transformation to DP-level control and ROV-follow capability.

The Mini-Ranger 2 was expertly integrated into the vessel along with human machine interfaces and GAMA and Sonardyne displays into pre-existing Simrad units on the Bridge. This was followed with extensive in-water testing and performance verification and calibration.

Through this work, Unique Group enabled GAMA to perform critical autonomous functions, including precise ROV following, station-keeping and survey line tracking off Australia’s West Coast.

The Results

Our collaboration with Tenggara Explorer demonstrates how high-precision station-keeping and target-following can be done without the DP price tag. With the integration of GAMA and Mini-Ranger 2, the vessel is proving its ability to deliver DP-level capability, including ROV-follow operations.

Kai Lebens, Director and Operations Manager, at Tenggara Explorer:

“What stood out most was the stability during ROV/AUV following. We consistently held position and heading within DP-equivalent tolerances, even in variable wind and swell, while following a moving subsea target through USBL updates. The feel is ‘DP-like’ – the helm simply stayed where it needed to be, without the constant micro-corrections they were used to.

With GAMA managing fine vessel motion, bridge teams can maintain higher vigilance and focus on project oversight, data quality and safety. It’s also an advancement on the autonomy roadmap – helping to unlock the benefits of autonomy, alongside DP-level control.”

Peter Baker, General Manager of Growth, at Greenroom Robotics:

“Mini-Ranger 2 provided the reliability and fidelity needed for predictive tracking. It provides high update rates, dependable accuracy and stable performance in the shallow-to-midwater environments typical of survey and inspection work.

“That consistency is essential as the autonomy needs trustworthy subsea positioning to predict vessel motion relative to the ROV/AUV. Sonardyne effectively gave us the ‘subsea truth source’ that GAMA’s Dynamic Predictive Control depends on.”

Aidan Thorn, Marine Robotics Business Development Manager at Sonardyne:

“For vessel operators like Tenggara Explorer, it means new mission types – allowing them to use their existing workboat to take on tasks that historically required a DP-class vessel, unlocking a broader variety, and potentially higher-value, jobs.”

“Unique Groups’ integration work was the linchpin that allowed the Tenggara Explorer to fully leverage the GAMA package and Mini-Ranger 2’s capabilities, enhancing operational efficiency and safety while reducing environmental risk,” adds Lebens (at Tenggara Explorer). “Their contribution was fundamental to the success of this project.”