JASCO advancing Passive Acoustic Monitoring via Unmanned Surface Vehicles
(Heave compensating winch and retrieved collapsible array on Seatrac SP48)
Between December 2024 and March 2025, JASCO led a multi-phase evaluation of a dipping passive acoustics system on a small solar-powered Unmanned Surface Vessel (USV) as part of the Innovative Solutions Canada Test Stream program.
The USV was equipped with JASCO’s collapsible spatial hydrophone array and heave-compensating winch, enabling acoustics monitoring traditionally performed by crewed vessels using a towed arrays. The dipping array system supports a sprint-and-drift operational concept that is more power efficient than traditional towed array approach enabling longer duration PAM missions. The technology demonstrated in this project can enable persistent maritime acoustics monitoring or surveillance missions.
Collapsible array expanded underwater
Three field trials were conducted off Massachusetts and Rhode Island using SeaTrac SP48 USV as the host platform:
Trial 1 – December 14, 2024 (Marblehead, MA)
Trial 2 – February 20, 2025 (Marblehead, MA)
Trial 3 – March 10–11, 2025 (Point Judith, RI)
JASCO’s proprietary dipping system operates similarly to a sonobuoy. The USV is piloted to a target monitoring area, set to drift, and the collapsible array is deployed through the vessels’ moonpool in the SP48 by the winch. Once the array reaches target depth, the arms expand to form a spatial array with the hydrophones. The winch then compensates for vessel motion to hold the hydrophones nearly motionless.
When the USV drifts out of the target zone, the array is retrieved back into the moonpool where it is streamlined and protected from heavy seas before the USV return to the deployment location.
Typically, hydrophones suspended from surface platforms such as boats or buoys experience motion from waves that can contaminate the acoustic data to a point where it is unusable except for very loud noises at higher frequencies. A key innovation with this system is the proprietary heave compensation method which effectively isolates the hydrophones in the collapsible spatial array from the USV motion at the surface.
As the result, the system offers operational capabilities similar to sonobuoys, while remaining reusable and suitable for long-duration deployments.
Technology Validation & Maturity Progression
The results demonstrated that:
The sprint-and-drift operational concept is effective for acoustic monitoring operations, and the heave compensation system was quiet.
Acoustic performance above 125 Hz met operational expectations in test conditions.
Testing across multiple trials enables refinements that reduced low-frequency system noise.
Real-time connectivity enables data access, system diagnostics, and remote configuration.
Bearing estimation can be achieved without left-right ambiguity.
The trials also identified targeted engineering enhancements to further improve array stability, deployment reliability, and acoustic noise floor performance — advancing the system toward higher technology readiness.
Scalable Applications Across Civil and Defence Domains
JASCO’s dipping acoustics system is a flexible acoustic platform capable of supporting:
(Vehicle on the surface)
(JASCO’s scientist directing the vehicle)
Environmental & Regulatory Monitoring
Marine mammal detection.
Real-time mitigation support.
Defence & Security
Anti-submarine warfare support.
Distributed acoustic surveillance.
Shallow-water monitoring.
Quieter platform operations with reduced hydrodynamic noise.
The project reflects JASCO’s current and future capability in providing high quality, low-cost PAM services and systems via Maritime Unmanned Systems. Unmanned systems have the promise of reducing the costs and personnel dangers associated with maritime PAM operations.
About JASCO Applied Sciences
JASCO Applied Sciences is a world leader in the science of underwater sound and its effects on marine life. A global company founded in Victoria, Canada, in 1981, JASCO provides services from offices in Canada, the United States, the United Kingdom, Germany, and Australia. We provide support for all stages of environmental reviews and assessments of underwater sound for the renewable energy, oil and gas, marine construction, shipping, and defence sectors. We design, develop, and manufacture state-of-the-art oceanographic data acquisition systems to meet project demands for quality, endurance, reliability, and performance. We enable our clients to satisfy regulatory requirements by providing scientifically defensible assessments of their projects to government regulators and the public. For more information, visit: www.jasco.com.