Ambient Noise Measurement and Characterization of Underwater Acoustic Channel in Surabaya Bay

Ambient Noise Measurement and Characterization of Underwater Acoustic

Channel in Surabaya Bay

Tri Budi Santoso, Endang Widjiati, Wirawan, Gamantyo HendrantoroElectrical Department, Institut Teknologi Sepuluh Nopember

IEEE Asia Pacific Conference on Wireless and MobileBandung-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. INTRODUCTION

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.

INTRODUCTION

• Description of Environmental Measurement• Hydrophone Normalization• Experimental Set-Up

II. ENVIRONMENT AND EXPERIMENTAL SET-UP

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 depthEnvironment temperature: 32.7o C, noise: 46.8 ~ 53 dB

ENVIRONMENT AND EXPERIMENTAL SET-UP

B. Hydrophone Normalization

Testing Signal: LFM 1~15 kHzReceiver: 3 hydrophonesADC: 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.

ENVIRONMENT AND EXPERIMENTAL SET-UP

C. Experimental Set-Up

H2

H1

Bottom

1.5

m

.

Surface

0.5

m

Bottom

Hydrophone

0.3

m

Perahu:PC-Recorder

Recording: 2 locations x three times, duration of 20 secondTotally obtain 18 data measurements

ENVIRONMENT AND EXPERIMENTAL SET-UP

III. DATA ANALYSIS

Time Domain Analysis Frequency Domain Analysis

A. Time Domain Analysis of Ambient Noise DATA ANALYSIS

Noise level fluctuations, around the zero level, Any part has a value of about -0.01 V or 0.01 V

DATA ANALYSIS

Statistical Analysis:Mean: -2.85 x 10-5 V, Standard deviation of 9.87 x 10-4 V

Fitting with Gaussian distribution:(mean=0, standard deviation, = 9.87 x 10-4)

-MSE : 9.96 x10-5

-Bhattacharya distance : 3.54 x 10-4

B. Frequency Domain Analysis of Ambient NoiseDATA ANALYSIS

Frequency range:0 ~ 9 kHz: decreasing - 90 dB ~ - 140 dBnegative logarithmic function : y = ln xa + 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. CONCLUSION

Ambient noise characterization: •Pdf is close to Gaussian distribution with zero mean, standard deviation of 9.87 x 10-4 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.