What can be heard or communicated underwater ?

The underwater environment is filled with a variety of acoustic signals, both natural and human-made. Marine mammals such as dolphins and whales use complex sounds for communication and navigation, making them important subjects of marine biology. Other sounds come from human activities, including echoes from geophysical sources, sediment movements, and the noise of passing cargo vessels.
These sounds can be detected and analyzed to map the seabed, evaluate environmental impacts, and identify underwater objects.
Vibrations are transmitted through both the water column and the seabed and can be monitored to track geophysical events, sediment shifts, and human influences.

Acoustic systems, like underwater modems, utilize these vibrations to transmit real-time data, including commands, coordinates, and sensor information. Consequently, acoustic listening and communication are vital tools for underwater monitoring and control.

Underwater acoustic communication relies on specialized equipment designed to withstand the ocean’s harsh conditions.

Acoustic modems transmit digital data using sound waves and are commonly used to communicate with underwater vehicles (AUVs/ROVs), submerged sensors, and fixed subsea stations. Fixed subsea station can use acoustic modems like the MATS 3G for passive acoustic monitoring applications.

Hydrophones are sensitive underwater microphones that detect and record ambient or targeted sounds. Mounted on masts, buoys, mobile platforms or ocean bottom seismometer (OBS), they enable passive listening of underwater environments. These technologies can be combined into complete systems, such as Sercel’s MicrOBS, which integrates three geophones or MEMS sensors and one hydrophone. This ocean bottom seismometer provides seabed monitoring at depths of up to 6,000 meters, with robust data recording capabilities in a modular device designed for autonomous, long-term deployment up to 180 days.
 

Several critical sectors benefit from underwater acoustic communication:

• Defense: Enables discreet communication with submarines, passive detection, underwater surveillance, positioning, and the protection of subsea infrastructure.

• Marine construction and offshore industry: Supports coordination of underwater operations, noise monitoring, and the control of ROVs/AUVs.

• Ocean monitoring: Facilitates biodiversity studies, seismic event detection, anomaly tracking, and the safeguarding of subsea infrastructure.

These markets demand high-performance, reliable systems capable of continuous operation in deep, remote, and often harsh environments. Equipment must meet the highest standards of durability, precision, and autonomy.
 

With decades of experience in underwater acoustic technology, Sercel is a recognized expert in underwater communication solutions.

The MATS 3G features a robust and versatile multi-modulation system designed to accommodate a wide range of applications and environments.

This advanced acoustic modem supports multi-sensor and high-data-rate antenna receivers, enhancing communication performance in shallow or noisy conditions. When needed, Sercel’s acoustic modems can also provide secure, stealth communication.