Over the last 5-10 years there have been ongoing trials around the world with naval Maritime Uncrewed Systems (MUS) conducting undersea surveillance experiments. Exercises such as REPMUS in Europe, Autonomous Warrior in Australia and Exercise Maritime Big Play across AUKUS partners all aim to advance the technological edge for the employment of MUS to support undersea warfare operations.
Acacia Systems has been at the forefront of operationalising the Royal Australian Navy’s (RAN) persistent undersea surveillance capability by providing the ability to network collaborative MUS and other sensors to automatically, detect, track and localise undersea targets at scale. Acacia is currently contracted to provide this capability for the RAN’s Operation RESOLUTE to support the protection of sovereign borders.
Operation RESOLUTE is currently deploying multiple USVs with lightweight towed arrays off the north-west coast of Australia to provide a 24/7 persistent undersea surveillance capability. This is the first deployment of an operational persistent undersea surveillance capability in the western world. In the European area of operations, Atlantic Net aims to operationalise experience from experimental programs such as CHARYBDIS, ASW Spearhead and the NATO Smart Barrier Initiative to provide “ASW as a Service” to increase mass and persistence over two years from 2026.
Acacia was selected to present at UDT 2025 and the presentation focused on the results of the trials conducted in Australia over the last 5 years. The 2026 paper will present an unclassified summary of the early lessons learned from Operation RESOLUTE and will provide an update on the following:
• Evolving Concept of Operations
• Over the air updating of capability
• Security considerations
• Evolving roadmap of platforms and sensors to support operations
These lessons learned can accelerate the implementation of new programs such as Atlantic Net.
This paper will be an update on the paper presented at UDT London 2026. The moderator of the session Domingo Gómez Pamo Guerra del Río, Senior Naval Advisor at Indra, said on completion of the presentation that it was one of the best presentations he had seen at UDT over the years. Domingo can be contacted on dgpamo@indra.es as a referee. This paper will advance the concepts presented at UDT London and cover the important role of multistatics in the future of persistent undersea surveillance.