Ultra Maritime has introduced a new sonar approach combining passive listening with active pinging to detect underwater drones and submarines. The system, unveiled in August 2026, uses a silent sensor array that waits for acoustic signals before triggering a second device to actively ping and locate the source. This method aims to improve detection while reducing the risk of revealing the hunter’s position.
The technology pairs the company’s Sea Spear passive sonar array with the AN/SSQ-125B active sonobuoy. The passive component listens continuously without emitting sound, allowing it to pick up subtle noises from enemy vessels or drones. Once a potential threat is detected, the system cues the active sonobuoy to send out a focused ping, refining the target’s location. This two-step process enhances stealth and accuracy in underwater surveillance.
Traditional sonar often relies on constant active pinging, which can alert adversaries to the presence of a detecting platform. By contrast, Ultra Maritime’s method remains covert until a contact is made. The Sea Spear array, designed for long-range passive detection, operates in tandem with expendable sonobuoys that activate only when needed. This conserves energy and reduces acoustic footprint, making it harder for hostile forces to evade detection or counter the surveillance effort.
The system is particularly suited for monitoring littoral zones where small, quiet drones and submarines operate. Naval forces have expressed interest in layered defenses that combine endurance with discretion. Ultra Maritime says the integration leverages existing hardware, allowing faster deployment without requiring entirely new infrastructure. Testing has shown improved signal clarity in noisy environments compared to standalone active or passive systems.
As underwater drones become more accessible and submarines grow quieter, traditional detection methods face growing challenges. The silent-then-active strategy addresses this by shifting the burden of detection to passive listening first, only engaging active sonar when a likely target is identified. This reduces false alarms and minimizes energy use during long patrols.
Officials note that the system does not eliminate the need for other sensor layers but adds a valuable tool for early warning and tracking. Ultra Maritime emphasizes compatibility with current naval networks, allowing data from the Sea Spear array and sonobuoys to feed into broader tactical pictures. Future upgrades may include AI-assisted signal filtering to further reduce response time.
How does the passive sensor know when to trigger the active sonobuoy? The Sea Spear array uses acoustic recognition algorithms to distinguish potential threat signals from background noise. When a signal matches predefined characteristics of a drone or submarine, it cues the AN/SSQ-125B to activate and ping the area.
Is the system effective against all types of underwater vehicles? It is optimized for detecting quiet, slow-moving targets such as electric drones and diesel-electric submarines in coastal or shallow waters. Performance may vary with faster, noisier nuclear submarines or in high-noise environments like heavy surf or shipping lanes.
Can the sonobuoys be reused after activation? No, the AN/SSQ-125B is an expendable device designed for single use. After transmitting its ping and relaying data, it is not recovered. This allows for wide-area deployment without retrieval logistics.