USBL system

This acoustic system is based on a transceiver and multiple transponders.


A transducer installed on the primary end of the segment to be immersed transmits an acoustic signal. This signal is received by two transponders, which have been attached to the previously-immersed segment. Their positions are measured in advance. The transponders emit an identifying signal in response to the transducer’s signal, which is received by the transducer. After various corrections for factors like sonic speed, the system is able to calculate the position of the transducer – and consequently the supporting segment – from the measured ranges and bearings.

Geocon employed the USBL system in the Busan-Geoje Fixed Link project.