Abstract—A target strength measurement is proposed in this paper using echo voltage reference from steel ball. The echo signal and target strength of the object observed using modified echo sounder model JMC V1082 operated at 200kHz.Sphere echo voltage reference is the best practical way in calculating target strength, especially when to quantify object at certain distance from the sound source. The goal of this experiment is to obtain target strength of the underwater object in fresh water using echo voltage reference technique and its variability for use in acoustic surveys of the shell animal. Underwater object (stainless steel ball, rock and tortoise) were positioned about 1 meter from the transducer face using nylon rope. Three objects selected in this experiment considered base on hard body and hard shell which is can give high backscattering strength. Target strength was calculated using echo voltage comparison between reference targets and underwater object. Two solid steel with different diameter (3.1cm & 2.2 cm) used in measurement to confirm target strength value. The envelope echo signal of three underwater object was recorded using high speed analog input USB1208HS and analyzed in matlab program. From echo observation in time domain, it is obviously shown that echo signal structure are different between the three underwater object. The higher echo voltage is from rock with TS value equal to -44.163 dB. Amplitude voltage from air filled stainless steel equal to 34.1mV and contributed -46.357 dB. The lowest TS value in this experiment is from Tortoise shell which is recorded -49.229 dB.

Index Terms—Echo sounder, Target Strength, Sphere,Tortoise

The authors are with the Faculty of Electrical and Electronic Engineering, Universiti Malaysia Pahang, 26600, Pekan, Pahang, Malaysia(e-mail: azrulpmu@yahoo.com.my; tel.: + 60199389279; fax:+6095663104).

Cite: A. Mahfurdz, Sunardi, and H. Ahmad, "Target Strength of Underwater Objects Using Echo Voltage Reference," International Journal of Computer and Communication Engineering vol. 1, no. 4, pp. 490-493 , 2012.