Underwater acoustic positioning system

Underwater Acoustic Positioning System is a method for locating equipment underwater. It is used in a variety of contexts where wireless communication or GPS navigation is not feasible.

Overview

An Underwater Acoustic Positioning System uses sound waves to determine the position of underwater objects. This is achieved by measuring the time it takes for a sound wave to travel from a transmitter to a receiver. The speed of sound in water is known, so the distance can be calculated from the time delay.

Types of Systems

There are several types of underwater acoustic positioning systems, including Long Baseline (LBL), Short Baseline (SBL), and Ultra Short Baseline (USBL) systems.

Long Baseline (LBL)

Long Baseline (LBL) systems use a network of transponders placed on the seafloor. The transponders communicate with a surface vessel or submersible, allowing for precise positioning.

Short Baseline (SBL)

Short Baseline (SBL) systems use a set of transducers located on a single vessel. The transducers emit and receive signals, and the system calculates the position based on the time delay of the received signals.

Ultra Short Baseline (USBL)

Ultra Short Baseline (USBL) systems are similar to SBL systems, but use a single transducer and multiple receivers. This allows for a more compact system, but with less precision than LBL or SBL systems.

Applications

Underwater acoustic positioning systems are used in a variety of applications, including underwater archaeology, marine biology, and offshore drilling. They are also used in the recovery of sunken objects, such as aircraft black boxes or shipwrecks.

See Also

• Sonar
• Underwater acoustics
• Underwater navigation