With each development cycle, endurance has improved, and sensors have become more capable, to the point that navies are investing heavily in autonomous systems and distributed maritime operations. But more vehicles and better payloads do not necessarily translate into meaningful capability. The real question is whether autonomous systems can operate at useful scale in contested waters—navigating, communicating, and completing missions without the conditions that almost never exist in wartime.
That challenge is particularly relevant in the Indo-Pacific, where distances between land are vast, GPS can be denied or spoofed, and vehicles may go several days submerged without a trusted position update. Navigation cannot be relegated to a supporting technology. It is the foundation of scalable success.
The Lessons of Ukraine Only Go so Far
Ukraine has shown the military value of autonomous systems and how quickly electronic warfare changes the fight. However, those lessons don’t translate directly underwater. An aerial drone can observe terrain; a surface vessel can use radar and visual references. By comparison, underwater platforms are nearly blind. Radio frequency doesn’t propagate through seawater, so communicating with a submerged vehicle generally requires a gateway—a buoy or surface vessel— that relays the signal acoustically. This creates a circular problem: the gateway must be placed near the vehicle, but if commanders don’t know where the vehicle is, they may not know where to place it. A navigation issue quickly becomes a communications problem.
Subsea Demand for More Autonomy
Acoustic signals travel slowly and support limited bandwidth— closer to text messaging than real-time video. Undersea systems therefore cannot depend on the persistent operator supervision that UAS operations in Ukraine rely on. Instead, they must execute mission intent and adapt with only semi-regular communication, which is even harder for kinetic operations, where identification is difficult and human review is constrained. For now, surveillance and sensing missions offer the most practical path for long-range undersea autonomy.
Drift Defines the Problem
Every inertial navigation system accumulates error, and small uncertainties compound over long distances. After several days and hundreds of miles, position uncertainty can become large enough to jeopardize a vehicle’s ability to reach a collection point, rendezvous with a gateway, or return to a recovery area. Current approaches often address this by achieving “bottom lock,” tracking movement relative to the seabed. The drawback is that this drives vehicle design: greater depths and pressures influence hull design, energy systems, materials, and cost. The vehicle becomes more expensive simply because navigation demands it.
Much of the discussion around autonomous systems focuses on production—how many vehicles can be built and fielded. But scale begins earlier, with design assumptions. If navigation requires every UUV to hug the seabed, fleets inherit significant cost and complexity. If reliable navigation can be achieved in the mid-water column instead, vehicles can operate at mission-appropriate depths rather than depths dictated by navigation— structures simplify, energy shifts toward range, and costs drop.
For UUVs in the Pacific, this is ultimately a scale problem: persistent surveillance requires enough vehicles to cover expansive areas and absorb losses. The undersea domain won’t experience its own drone revolution through payloads alone—it will happen when vehicles can operate persistently, at range, and at a cost that allows fielding in meaningful numbers.
What Comes Next?
Navigation has become an area of intense investment across government, industry, and academia, with growing recognition that undersea autonomy won’t scale unless vehicles can maintain trustworthy position estimates for long periods without GPS. Emerging approaches include better inertial sensors and algorithms, terrain- and seabed- relative navigation, and fused architectures combining inertial, acoustic, and environmental inputs. Communications are seeing similar investment, from autonomous relay systems to adaptive networking.
Perhaps more importantly, the industry is beginning to rethink how much communication is necessary. For decades, the assumption was that better systems receive more information and direction. Underwater autonomy may push us toward the opposite conclusion—the most effective vehicles may be the ones that require fewer updates, operate independently longer, and communicate only when mission requirements demand it.
The future of undersea autonomy will be determined not by how much capability we place aboard a vehicle, but by whether that vehicle can navigate with confidence when support disappears. That shift has implications beyond engineering: commanders must decide what authorities are delegated to the vehicle, what decisions require human intervention, and how systems should behave when communications are unavailable.
Today, the undersea domain must be approached as a navigation challenge, not a communications challenge. Once you know where you are, many other problems become manageable. Navigation isn’t merely another undersea requirement— it’s the foundation that makes every other capability matter.
