This USBL system is designed for low-cost, medium accuracy localization of underwater objects. It can be used to guide an ROV to an area of interest, either manually or autonomously. The system can also locate an ROV among other possible applications.
A complete system requires both a transmitter and a receiver. After calibration, transmitters are paired with specific receivers and should not be interchanged. The system works by syncing the clocks of a transmitter and receiver. The transmitter then sends a sound pulse once per second. The receiver uses time-of-flight to calculate slant range to the transmitter and phase measurements to determine the arrival angle of the sound pulse.