ATLAS North America Proprietary
Sea Scan® ARC Explorer™ Manual
1 of 1
Page: 7
Issue: 4.2.1
2SFT1-0001
Manual
2
Introduction to Side Scan Sonar
2.1
General Sonar Overview
Sonar is a coined word derived from the phrase, Sound Navigation And Ranging. Sonar generally
refers to a system that uses acoustical (sound) energy transmitted through water. At the heart of
that system is the transducer, the device that converts electrical energy to sound and vice versa
and is responsible for generating the sound pulse. A receiving transducer is used to receive the
echo that “bounces” off objects encountered along its path
Figure 1: The transducer sends out a pulse
Figure 2: The pulse bounces off the object
Thus, sonar is a system that determines the position of unseen underwater objects by transmitting
sound waves and measuring the time it takes for their echo to return after hitting the object.
2.2
How Side Scan Sonar Works
Because of their flexibility, side-scan systems can be used in many applications , some of which
involve highly sophisticated remotely operated vehicles (ROVs), autonomous underwater vehicles
(AUVs) or a towed system. The most common side-scan systems are towed behind a surface
vessel and comprise three elements: the control unit containing the software, the towfish with
transducers mounted on each side, and the cable that connects the towfish to the surface vessel
that follows a track or course through the water. The images they create can be used for many
applications such as geologic studies, locating sunken objects, ensuring that the waterway is clear
and safe for shipping, and many more.
The transducer assembly moves on a steady course and at a constant depth through the water. As
it is moves through the water, the assembly emits sound pulses at precise and regulated intervals.
Figure 3: The system emits precise sound pulses
