IMPACT SUBSEA
INNOVATIVE UNDERWATER PRODUCTS
www.impactsubsea.com
Document No:
0000.1991 |
Version No:
1.6 | 6
th
October 2020
29
6.2 The Sonar Equation
Any equipment which relies on underwater acoustics for ranging purposes falls into the category of
a Sonar, hence the operation is governed by the 'Sonar Equation'.
A clear understanding of this Equation is essential in the design of any acoustic equipment, and is
useful for those wishing to utilise acoustic equipment to its full potential.
The Sonar Equation is a fundamental equation, which is at the heart of all hydro-acoustic systems:
SL – TL – (NL – DI) > DT
SL
= Source Level
TL
= Transmission Loss
NL
= Noise Level
DI
= Directional Index
DT
= Detection Threshold
6.2.1 Source Level (SL)
The Source level is the power at which the acoustic pulse is put into the water. A greater
source level will increase the range capability; however, it will also increase the power
consumption.
Therefore, a trade-off between power consumption of the device and the range required
must be achieved.
There is also a physical limit to the Source Level; which can be achieved underwater before
cavitation occurs, and acoustic transmission breaks down.
