Question :
Sonar Equation A vessel is using a 180 kHz side sonar exploring the marine environment. The active diameter of the circular sonar transducer is 3.5 cm. The measured sound pressure 1 m in front of the transducer is 11 uPa.
A pulse is transmitted and an echo is returned from 200 m range. The received echo strength signal is 150 a.
a) What is the source level (SL) in dB?
b) What is the absorption at 180 kHz?
c) What is the directivity index?
d) What is the transmission loss in each direction assuming spherical spreading loss in the first 25 m?
e) What is the target strength (TS) of the target?
f) What is the figure of merit (FOM) in a port environment with a background noise level of 100 dB?