AUVs

Autonomous underwater vehicles (AUVs) are untethered, programmable underwater machines designed to operate independently of human control and without real-time communication with a surface vessel. They are deployed for scientific research, seabed mapping, infrastructure inspection, and military and commercial applications. AUVs follow pre-defined missions, use onboard sensors to collect data, and return with the gathered information, either by surfacing or by storing data for later retrieval.

Most AUVs are powered by batteries and use propulsion such as electric thrusters, buoyancy control, or buoyancy-driven gliders. They carry a suite of sensors, including sonar (multibeam or sidescan), cameras, and environmental sensors, along with navigation instruments. Underwater navigation relies on inertial measurement units, Doppler velocity logs to measure speed relative to the seafloor, depth sensors, and sometimes acoustic positioning when within range of surface ships or transponder networks. Precise navigation is achieved through estimation techniques and periodic surfacing or beacon-based updates, since standard GPS is not available underwater.

Operation is driven by mission planning software that specifies waypoints, survey patterns, and sampling schedules. AUVs are typically deployed from ships or coastal facilities, can operate for hours to weeks depending on energy capacity, and may return to surface to transmit data and be recovered. Some systems are capable of coordinating with other vehicles or swarms to increase coverage and efficiency.

Applications and challenges: AUVs are used in oceanography, marine geology, hydrographic surveying, offshore infrastructure inspection, underwater archaeology, search and salvage, and defense-related tasks such as mine countermeasures. Challenges include limited endurance, harsh deep-sea environments, data management needs, reliability, and restricted real-time communication, all of which shape ongoing research and development in the field.