Sonar-equipped autonomous ocean drones hunt subsea threats

Tanya Weaver Tue 8 Apr 2025

Collected at: https://eandt.theiet.org/2025/04/08/sonar-equipped-autonomous-ocean-drones-hunt-subsea-threats

Saildrone and Thales have trialled a scalable, cost-effective system capable of autonomously scouring the oceans to detect undersea and surface threats.

In the firms’ most recent collaboration, US ocean drone company Saildrone integrated the BlueSentry thin-line towed sonar array from defence company Thales Australia into its Surveyor-class uncrewed surface vehicle (USV). 

They have now completed a trial that has seen persistent undersea and surface surveillance conducted in Saildrone’s fully autonomous, long-endurance vehicle.

Saildrone develops USVs capable of performing long-range, long-endurance missions in the open ocean to obtain real-time data.

Last year, Saildrone announced that its SD-3000 aluminium Surveyor-class USV was to begin testing with the US Navy  to help map the seafloor to depths of 36,000ft (11,000 metres). 

During the continuous 26-day mission off the coast of California, the BlueSentry sonar system showed an ability to detect and track surface vessels, submarines and unmanned underwater vehicles.

Detections were transmitted in real time via Starlink and Iridium satellite communication links, supporting real-time decision-making from remote locations worldwide.

The Saildrone-Thales system also proved it was able to maintain continuous surveillance even across high-traffic areas where traditional maritime security assets are stretched thin and face significant operational challenges.

The 20-metre-long Surveyor is powered by renewable wind and solar power. The trials showed that, under wind propulsion, the USV provided a near-zero self-noise environment, which helped to significantly improve the detection capabilities of the BlueSentry sonar system.

The successful trial, funded by the US Office of Naval Research, proves that the Saildrone-Thales system provides a scalable, low-cost alternative to traditional surveillance platforms.

Deployed at scale, these systems could help boost the AUKUS trilateral security partnership between Australia, the UK and the US in the Indo-Pacific.

Jeff Connolly, CEO of Thales Australia and New Zealand, said: “The successful test has proven the new system’s ready-to-deploy capabilities which can be used to detect drug trafficking, enemy submarines or even people smuggling vessels in difficult-to-monitor areas, offering a powerful capability and real-time identification and tracking for both military and government customers.”

Richard Jenkins, founder and CEO of Saildrone, said: “The acoustic performance of the BlueSentry array, paired with a platform as silent and capable as the Saildrone Surveyor, represents a considerable step forward in undersea observation.

“The extreme endurance of the system allows us to put eyes and ears in places that were previously out of reach, at a cost point orders of magnitude below traditional manned surveillance platforms.”