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58 White Part IV Table 1: Target, environment, and sensor setups for the different measurements where the sound velocity is given as c and Depth is sensor depth. Setup Target Bottom c [m/s] b mn [m] Depth [m] 1 1 rocks 1421 17-181 9-14 2 2 mud 1485 90-141 13-18 Table 2: Size, velocity, and placement of Targets. Target Size [m] Speed [m/s] Propellers Placement 1 20x8.0 2.5 2 surface 2 4x1.5 0 1 surface b mn in 1A, while in 1B the baseline is bigger then the distance. In Measurement 1A, the target is far away from the coastline while in 1B the coastline, is ∼ 150 m on the opposite side of the target in comparison to the sensor network. In Measurements 1A and 1B, the target is moving with a velocity of 2,6 m/s, while in measurement 2 the target is not moving. According to Tables 1 and 2, the target in Measurement 2 is very small in comparison to the target in Measurement 1. Note that the bottom condition with rocks in Setup 1 gives stronger bottom reflection than in Setup 2 where the bottom is covered with mud as is shown in Table 1. During the experiment, the positions of sensors and targets were measured with a Differential Global Positioning System, DGPS, which gives a deviation of 0,5 to 5 m. 3.2 Target sound Frequency spectra of the received signals in Setup 1 is shown in Fig. 4 and Fig. 5, and only an estimate of the frequency spectra of one sensor is shown for Setup 2 because the sensor signals were not satisfactorily calibrated in this experiment. This absolute calibration error is, however, not important for the final result, since PHAT weighting of the GCC will normalize all frequencies resulting in an amplitude equal to one in the frequency plane. The frequency spectra in Fig. 4 and Fig. 5 are from the same target and thereby the spectra are similar. They decay in both setups as the frequency increases. However, there is a broad peak at 10,000 Hz for Measurement 1A in comparison to 1B. A reasonable explanation for the peak in 1A could be that the stern of the target is sensed by several sensors and thereby the noise from the cavitation of the two propellers is registered. In spectra for Measurement 1B, there is an indication that tonals are registered from the target. This can also can be confirmed by the sound files. In Measurement
Imaging of moving continious broadband sound source within a sensorfield 59 Figure 1: Example of setup where geometric parameters are defined. 800 Setup 1A 800 Setup 1B 2 2 750 6 5 750 6 5 2.6 m/s 700 700 Y [m] Y [m] 650 650 3 4 3 4 600 1 600 1 550 0 50 100 150 200 250 X [m] 2.6 m/s 550 0 50 100 150 200 250 X [m] a) Measurement 1A b) Measurement 1B Figure 2: Setup 1. In Measurement 1A, the distance to all sensors is approximately the same, while in Measurement 1B the distances are very different. The water environment is given in Table 1 and target properties are given in Table 2.
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Passive Acoustic Monitoring of Movi
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Blekinge Institute of Technology Li
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White White White White Abstract v
Page 9: White White White White vii Preface
Page 13: White White White White xi Contents
Page 16 and 17: 14 White White White White 2005 MTS
Page 18 and 19: 16 White Introduction White White f
Page 20 and 21: 18 White Introduction White White C
Page 22 and 23: 20 White Introduction White White C
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Page 26 and 27: 24 White Introduction White White P
Page 28 and 29: 26 White Introduction White White R
Page 30 and 31: Part I has been published as: Zette
Page 32 and 33: 30 White Part I III. GENERALIZED CR
Page 34 and 35: 32 White Part I Fig. 6 show a momen
Page 36 and 37: 34 White Part I REFERENCES [1] B. X
Page 38 and 39: Part II has been published as: Zett
Page 40 and 41: 38 White Part II GCC function [4] i
Page 42 and 43: 40 White Part II C. Frequency depen
Page 44 and 45: 42 White Part II a pair, thereby en
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Page 48 and 49: 46 White Part III xm 1 ( t) s( t)
Page 50 and 51: 48 White Part III VI. RESULTS To il
Page 52 and 53: 50 White Part III ACKNOWLEDGMENT Th
Page 54 and 55: Part IV i submitted as: Zetterberg,
Page 56 and 57: 54 White Part IV capabilities and t
Page 58 and 59: 56 White Part IV However, with the
Page 62 and 63: 60 White Part IV 1B, the engine sou
Page 64 and 65: 62 White Part IV 140 130 Magnitude
Page 66 and 67: 64 White Part IV coordinate system
Page 68 and 69: 66 White Part IV Table 3: Differenc
Page 70 and 71: 68 White Part IV drawn for zero del
Page 72 and 73: 70 White Part IV 60 Bandwidth depen
Page 74 and 75: 72 White Part IV 5.2.2 Results For
Page 76 and 77: 74 White Part IV Figure 15: Setup 1
Page 78 and 79: 76 White Part IV 5.3.2 Results The
Page 86 and 87: 84 White Part IV 4040, Orlando, FL,
Page 90: ABSTRACT Surveillance of sound acti
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