The new system relies heavily on passive acoustics—technology that simply listens, rather than sending out signals of its own such as sonar pings.
Australia is building an integrated undersea capability. This includes a mix of seabed sensor nodes, towed sonar, autonomous underwater vehicles (AUVs), uncrewed surface vessels (USVs), and data fusion/artificial intelligence—all to monitor its northern approaches and protect critical undersea infrastructure.
The work is being driven by industry partners and Australia’s Ministry of Defense. It is designed to align with the Australia-United Kingdom-United States (AUKUS) alliance.
The key factor driving this new push from Australia is China, which has both become increasingly belligerent toward Canberra as well as extended its geostrategic reach beyond the First Island Chain.
About Australia’s Secretive Detection Project
Australian defense research-and-development agencies are involved. Industry teams named in recent announcements include Thales Australia, Austral, and C2 Robotics. Anduril Australia also has large contracts for uncrewed undersea systems.
This is a distributed, persistent undersea/watch-theater network made up of seabed sensor nodes and passive acoustic arrays. There will be towed arrays and thin-line sensors deployable from surface platforms, too.
Long-endurance AUVs/gliders and USVs that carry sensors and communications relays will be built. Lastly, cloud/AI data fusion capabilities will be created to establish near-real-time maritime domain awareness.
Australia is concerned about Chinese incursions into their territorial waters. These systems are being made to detect (and deter) hostile submarines or underwater threats at key northern chokepoints, all to bolster AUKUS undersea capabilities—and to better protect critical undersea infrastructure such as international fiber optic cables.
Australian military leaders have flagged undersea vulnerabilities as an existential risk.
The New Detection Network Will Rely on Drone Technology
Some of the technologies involved, such as passive acoustics will basically be Australia’s “ears” under the sea. They will listen for sounds made by submarines, ships, torpedoes, or other vehicles. Notably, these sensors don’t transmit anything, so they are stealthy, keeping them in turn from being detected by their would-be quarry. They use hydrophones (underwater microphones) to pick up propeller noise, cavitation (tiny bubbles made by moving blades), flow noise around a submarine, hill, and even very faint mechanical hums.
As noted above, Australia intends to place these sensors on the seabed to form fixed listening posts. AUVs would roam slowly and quietly. USVs would trowel the surface, towing long cables full of hydrophones to ensure redundancy in the detection grid that Canberra is establishing.
There’s also the more active “ping and listen” active sonar. It has been described as “shouting and listening for echoes” beneath the sea. The sonar system sends out a loud pulse—the ping—then measures how long it takes for the echo to bounce back from an object. This system can detect silent or stationary objects that the passive sensors would miss. With that said, this loud system reveals itself because of those pings. It uses more energy than the passive sonar does. And it can disturb marine life if not carefully managed.
Active sonars can be used selectively. Patrolling AUVs or drones would deploy active systems when they detected a suspicious noise. Fixed seabed stations could also engage the active sonar after the passive system detects something faint. They can also be used in a training or testing mode and would not, therefore, be in constant use—meaning marine life would largely be left alone.
The benefit of utilizing Autonomous Underwater Vehicles is that they can move quietly under the sea without the need for a crew. They carry sensors such as hydrophones, sonar, cameras, magnetometers, etc. They can patrol long routes or sit stationary to listen for hours or days. Some models can even map the seabed or inspect undersea cables and pipelines (since this form of undersea warfare is increasingly popular with the Chinese navy today). In fact, Australia’s local industry is developing long-range AUVs that can stay underwater for months, recharging at undersea “docking” stations.
Then there are the USVs, naval drones that operate along the surface. They can act as both sensors and communication relays, linking underwater sensors to satellites or land-based control centers. These systems can patrol in coordinated groups, or swarms, to cover huge areas.
The seabed sensor nodes come in the form of anchored pods or clusters of sensors along the ocean floor. These are usually installed at the ocean floor, often at chokepoints or along undersea cables. They continuously listen and sometimes send data bursts to nearby USVs or underwater relay buoys. Some may form a grid of passive sensors, much like the Cold War-era Sound Surveillance System (SOSUS) that the US used across the Atlantic and Pacific—but this one would employ modern AI and data fusion.
All the sound and sensor data—millions of small signals—flow into shore-based or cloud systems that use AI pattern recognition to distinguish whales from submarines. These systems can also triangulate positions using multiple sensors. They form a live “underwater situational picture” of what’s happening in Australia’s surrounding seas. This digital layer is what turns the hardware into a real surveillance network.
Will the New System Keep Australia Safe?
Rounding out this new, layered detection network is how it will all feed into AUKUS Pillar II projects on undersea domain awareness and autonomous systems. Data from Australian waters could integrate with American and British undersea networks—giving a continuous “acoustic curtain” across key Indo-Pacific sea lanes.
The sub-sea network would further protect undersea cables and infrastructure, which are vital for communications and trade—especially for Australia, which is geographically isolated from the rest of the region.
All in all, Australia is attempting to stand up to China in ways that it previously would never have countenanced. Ever since COVID-19, the Australians have gotten more serious about deterring aggression from China and overreliance on trade with China.
This new sub-sea network is incredibly ambitious. But it just might be what’s needed to keep Australia competitive at a time when China is mostly running geopolitical and geoeconomic circles around its rivals.
About the Author: Brandon J. Weichert
Brandon J. Weichert is a senior national security editor at The National Interest. Recently, Weichert became the host of The National Security Hour on America Outloud News and iHeartRadio, where he discusses national security policy every Wednesday at 8pm Eastern. He is also a contributor at Popular Mechanics and has consulted regularly with various government institutions and private organizations on geopolitical issues. Weichert’s writings have appeared in multiple publications, including The Washington Times, National Review, The American Spectator, MSN, and the Asia Times. His books include Winning Space: How America Remains a Superpower, Biohacked: China’s Race to Control Life, and The Shadow War: Iran’s Quest for Supremacy. His newest book, A Disaster of Our Own Making: How the West Lost Ukraine is available for purchase wherever books are sold. He can be followed via Twitter @WeTheBrandon.
Image: Wikimedia Commons.
