Listening on an Energy Budget: A Detecting Floater Platform for Underwater Acoustic Surveillance
Distributed networks of small, low-cost devices, the Internet of Underwater Things (IoUT), offer a new way to monitor the marine environment. Deployed from moorings, vessels or aircraft, swarms of such devices can scan the water column acoustically and cooperate to detect ships, AUVs or other threats to offshore infrastructure. Their main limitation is energy: with little opportunity to recharge at sea, operation time is measured in days rather than months.
This talk presents progress in a NATO SPS project that tackles this challenge along three complementary lines: an energy-efficient detecting floater platform, acoustic detection with small hydrophone array, and harvesting renewable energy from the ambient acoustic noise itself using polymer-based transducers. Together these aim at a five-platform swarm demonstrator able to operate for months without charging.
The presentation focuses on the detecting floater platform. Its primary role is to listen: to hold a chosen depth and remain acoustically quiet, while spending as little energy as possible on doing so. The platform is designed to be easily extensible, so that new payloads and modules can be easily integrated. Recent work targeted three goals: reducing the acoustic footprint of buoyancy adjustments, reducing power consumption while keeping acceptable depth-keeping performance, and reducing the electronics power footprint. We present the resulting improvements and lessons learned.