The gfai tech HydroVision SeaStar24 is a passive underwater acoustic imaging system that turns ambient underwater sound into real-time 2D and 3D spatial visualizations. Its dual-ring array of 24 broadband hydrophones captures acoustic energy across 1.5–20 kHz and applies phase-coherent digital beamforming to localize sound sources without emitting a single acoustic pulse. The result is an underwater surveillance camera that can detect, track, and classify divers, surface vessels, and underwater vehicles silently — without revealing its own presence or disturbing marine life.

How does passive acoustic imaging work underwater?

Every vessel, diver, and underwater tool radiates acoustic energy — propeller cavitation, engine vibration, hull turbulence, breathing apparatus, impact noise. The SeaStar24's 24 hydrophones sample the sound field at known geometric positions on a dual-ring frame. On-shore or on-vessel signal processing computes the direction of arrival for each frequency component using beamforming algorithms, then overlays the resulting source map onto a visual reference of the monitored area. The system updates in real time, providing a live acoustic image comparable in concept to a thermal camera — but operating in complete darkness, turbidity, and acoustically.

What makes passive sonar different from active sonar for surveillance?

Active sonar transmits a high-power acoustic pulse and listens for the echo — effective, but it announces the sensor's position to every vessel and submarine in range, disturbs cetaceans, and is often prohibited in environmentally sensitive waters. The SeaStar24 transmits nothing. It listens only, making it inherently covert and environmentally benign. The trade-off is range: passive acoustic imaging works best at distances from a few meters to a few hundred meters, depending on target noise level and ambient conditions, whereas active sonar can reach kilometers. For port-perimeter gaps, offshore platform exclusion zones, and underwater checkpoint screening, the passive range envelope is well matched to the operational requirement.

How is the SeaStar24 deployed?

The array body measures 1,750 × 1,750 × 605 mm and weighs approximately 14 kg without its stand, fitting in a transport case of 1,041 × 1,041 × 412 mm. Deployment options include three-point suspension from a quayside crane or seabed mounting on a custom frame. Power and data run over a single Ethernet cable to a shore- or vessel-based processing station. The system has been tested to 22 m depth and is rated for up to 30 m operational environment, with a maximum continuous underwater operating time of 10 hours. gfai tech offers the SeaStar24 as a pre-series product available for project-based deployment and cooperative development — specifications beyond the published data sheet are available on request.