Overview
Autonomous Underwater Vehicles (AUVs) are self-propelled, unmanned underwater vehicles that can perform tasks with little or no human supervision. They are used for ocean-based research, such as mapping the seafloor, studying ocean properties, and measuring ambient noise. AUVs have advantages such as reaching shallow and deep waters, operating in bad weather, being scalable with different sensors, and being less expensive than research vessels.
AUVs are also used for measuring underwater noise, and advancements in technology have made underwater noise measurement more accessible with commercial autonomous recorders. AUVs have been used in the Indian Ocean region for various maritime missions, with the Defense Research and Development Organisation (DRDO) in India developing multiple AUV prototypes for operational requirements. Mapping the noise created by ships is important both for defense and marine conservation purposes. Underwater ambient noise in shallow-water areas of the tropical zone of the Indian Ocean is characterized by higher level spectral maxima, which distinguish this type of noise from the noise in the deep-water ocean. A moving array, such as a line array towed behind a moving AUV, provides distinct advantages for the measurement of the ambient noise field.
Key highlights
- An AUV is an unmanned, self-propelled underwater vehicle used for ocean-based research and surveying.
- AUVs can reach deeper water than human divers or tethered vehicles, and can stay underwater for extended periods of time.
- AUVs are modular and can be customized with different sensors depending on research objectives.
- AUVs are less expensive than research vessels, but can complete identical surveys of an area.
- Shipping has become a dominant source of low-frequency ambient noise in the ocean, and AUVs can be used to measure and map this noise.
- Autonomous recorders with hydrophones are increasingly used for measuring underwater sound, and can be deployed with smaller AUVs.
- The Defense Research and Development Organisation (DRDO) in India has developed AUV prototypes for maritime missions.
Key Challenges
- Power optimization: AUVs require power for propulsion, sensors, communication, and data processing. Optimizing power consumption while maintaining operational requirements is a challenge.
- Testing: AUV testing presents challenges in terms of simulating real-world conditions and ensuring the vehicle operates safely and effectively.
- Collision avoidance: AUVs must be equipped with collision avoidance systems to prevent damage to the vehicle and ensure safe operation.
- Position monitoring: Accurate monitoring of an AUV’s position is critical for effective navigation and data collection.
- Procedures must be in place to deal with potential failures, such as overheating or water seepage, to ensure the safety of the AUV and any personnel involved.
Major Opportunities
- AUVs can provide researchers with a versatile and efficient platform for measuring ambient noise in the ocean, particularly in shallow water areas where shipping noise is dominant
- Access to difficult or inaccessible areas for humans, providing new insights into unexplored environments.
- AUVs can enable researchers to study underwater environments that are difficult to access using traditional research methods
- The development of autonomous recorders for measuring underwater noise has increased the capability for ocean noise measurement without the need for bespoke designs that require great expertise to set up and operate.
“AUVs are self-propelled, unmanned, untethered underwater vehicles used for ocean-based research. They can reach shallower and deeper waters than boats or human divers, can stay underwater for extended periods of time, and are scalable, meaning that scientists can choose which sensors to attach to them depending on their research objectives”.
