Ambient Noise Measurement and Characterization of Underwater Acoustic Channel in Surabaya Bay Tri Budi Santoso, Endang Widjiati, Wirawan, Gamantyo Hendrantoro Electrical Department, Institut Teknologi Sepuluh Nopember IEEE Asia Pacific Conference on Wireless and Mobile Bandung-Indonesia, August 27-29, 2015

Outline Presentation Introduction Environment and Experimental Set-Up Data Analysis Conclusion

Ambient noise[1][2]: Generally appears continually at a certain location. Determines the baseline sound scape I. I NTRODUCTION Current Research: The effects of wind and ship movement on acoustic noise [5] – [11] Time-frequency analysis of ambient noise measurement [12] Effect of seabed conditions in shallow waters on ambient noise [13][14]

This paper: Present measurement and characterization of ambient noise that has been conducted in coastal environments of Surabaya. Represent a condition of tropical shallow water environment. I NTRODUCTION

Description of Environmental Measurement Hydrophone Normalization Experimental Set-Up II. E NVIRONMENT AND E XPERIMENTAL S ET -U P

A. Description of Environmental Measurement Coordinates: (7°0′~7°30′(S); 112°30′~113°0′(E)) Relative busy traffic, 200 m from beach, 2.4 m depth Environment temperature: 32.7 o C, noise: 46.8 ~ 53 dB E NVIRONMENT AND E XPERIMENTAL S ET -U P

B. Hydrophone Normalization Testing Signal: LFM 1~15 kHz Receiver: 3 hydrophones ADC: Digital Mixer (M-Audio) Ratio between hydrophones: H-123 : H-2 = 1.9, H-ref : H-2 = 0.65, H-123 : H-ref = 1.7. E NVIRONMENT AND E XPERIMENTAL S ET -U P

C. Experimental Set-Up Recording: 2 locations x three times, duration of 20 second Totally obtain 18 data measurements E NVIRONMENT AND E XPERIMENTAL S ET -U P

III. D ATA A NALYSIS Time Domain AnalysisFrequency Domain Analysis

A. Time Domain Analysis of Ambient Noise D ATA A NALYSIS Noise level fluctuations, around the zero level, Any part has a value of about V or 0.01 V

D ATA A NALYSIS Statistical Analysis: Mean: x V, Standard deviation of 9.87 x V Fitting with Gaussian distribution: (mean=0, standard deviation,  = 9.87 x ) -MSE : 9.96 x Bhattacharya distance : 3.54 x 10 -4

B. Frequency Domain Analysis of Ambient Noise D ATA A NALYSIS Frequency range: 0 ~ 9 kHz: decreasing - 90 dB ~ dB negative logarithmic function : y = ln x a + b. a = -11.5, b = -30. Frequency range: 9 ~ 13.5 kHz, noise power level is quite flat Frequency range: 14 kHz ~ 18 kHz, noise power level has a fluctuation

IV. C ONCLUSION Ambient noise characterization: Pdf is close to Gaussian distribution with zero mean, standard deviation of 9.87 x V. Frequency range (9 kHz ~ 13.5 kHz), shows a flat spectrum, represents an AWGN channel conditions. The modeling of UWA communication system can be done by adopting the model of digital communication systems in AWGN channel, in the frequency range.