【摘要】：隨著海洋科學(xué)的發(fā)展,光纖水聽器的應(yīng)用領(lǐng)域越來越廣。比起傳統(tǒng)的光纖水聽器,聲光耦合干涉型光纖水聽器可以在空中機(jī)載平臺發(fā)射探測激光,在水面通過激光多普勒效應(yīng)耦合水下聲場信患,通過檢測反射光信號遙感測量水下聲場信號。聲光耦合干涉型光纖水聽器不僅靈敏度高,而且可以對危險海域進(jìn)行非接觸式探測,是一種非常有潛在應(yīng)用價值的傳感器；本論文首先介紹了光纖水聽器發(fā)展歷史和聲光耦合型光纖水聽器的應(yīng)用；研究分析了一種基于7r/2相位調(diào)制的聲光耦合干涉型光纖水聽器,介紹利用這種調(diào)制方法獲取兩路正交信號的原理；詳細(xì)介紹了兩種常用的光纖水聽器數(shù)字解調(diào)方法,微分交叉算法和反正切算法,分別分析這兩種解調(diào)算法的動態(tài)范圍上限以及動態(tài)范圍受限原因,對比這兩種解調(diào)算法的優(yōu)缺點；提出了微分交叉相乘算法無畸變動態(tài)范圍的概念,通過分析其解調(diào)原理發(fā)現(xiàn)其動態(tài)范圍上限隨采樣頻率線性增大；通過Matlab仿真,分析了信號幅度、頻率和采樣頻率對這兩種解調(diào)算法的影響；并研究了當(dāng)待解調(diào)的兩路信號處于非正交的狀態(tài)時對兩種解調(diào)算法的影響。搭建了基于PZT環(huán)的π/2相位調(diào)制干涉實驗系統(tǒng),對振動信號進(jìn)行解調(diào)測試,實驗結(jié)果證明該解調(diào)系統(tǒng)最小可檢測相移量為2.4×10-5rad,系統(tǒng)的動態(tài)范圍受信號頻率和采樣頻率的影響,當(dāng)信號頻率從5kHz變化到1kHz,系統(tǒng)無畸變動態(tài)范圍從87dB提高到102dB。搭建了聲光耦合型干涉水聽器實驗系統(tǒng)進(jìn)行水池實驗,探測到了水下10m處鋁板的反射聲波信號。根據(jù)實驗結(jié)果分析,聲光耦合型干涉水聽器可檢測最大深度為36m。最后提出了一種利用激光聲源和聲光耦合干涉型光纖水聽器陣列探測水下目標(biāo)方位和尺寸的方法,分析其工作原理。介紹了使用的差分定位算法和解卷積算法分別來估算水下目標(biāo)方位和尺寸的原理。最后對探測系統(tǒng)進(jìn)行了數(shù)值仿真,驗證了這種方法的可行性。
[Abstract]:With the development of marine science, the application field of fiber optic hydrophone is more and more extensive. Compared with the traditional fiber optic hydrophone, the acousto-optic coupled interferometric fiber optic hydrophone can launch and detect the laser on the airborne platform and coupling the underwater acoustic field signal through the laser Doppler effect on the surface of the water. The underwater acoustic field signal is measured by remote sensing by detecting the reflected light signal. The acousto-optic coupled interferometric fiber optic hydrophone is not only of high sensitivity, but also can be used for non-contact detection of dangerous sea areas. It is a kind of sensor with potential application value. Firstly, the development history of fiber optic hydrophone and the application of acousto-optic coupling fiber optic hydrophone are introduced. An acousto-optic coupling interferometric fiber optic hydrophone based on 7r/2 phase modulation is studied and analyzed. The principle of obtaining two orthogonal signals by this modulation method is introduced. In this paper, two digital demodulation methods of fiber optic hydrophone, differential crossover algorithm and anti-tangent algorithm, are introduced in detail. The upper limit of dynamic range and the reason of limitation of dynamic range of the two demodulation algorithms are analyzed respectively. The advantages and disadvantages of the two demodulation algorithms are compared. The concept of differential cross multiplication algorithm without distortion dynamic range is proposed. By analyzing the demodulation principle, it is found that the upper limit of the dynamic range increases linearly with the sampling frequency. Through Matlab simulation, the influence of signal amplitude, frequency and sampling frequency on these two demodulation algorithms is analyzed, and the influence of the two demodulation algorithms when the two signals to be demodulated are in non-orthogonal state is studied. A 蟺 / 2 phase modulation interference experiment system based on PZT loop is built and the vibration signal is demodulated. The experimental results show that the minimum detectable phase shift of the demodulation system is 2.4 脳 10 ~ (- 5) radd. The dynamic range of the system is affected by the signal frequency and sampling frequency. When the signal frequency changes from 5kHz to 1kHz, the distortion-free dynamic range of the system increases from 87dB to 102dB. An acousto-optic coupled interferometric hydrophone experiment system was set up to carry out the pool experiment, and the reflected acoustic signal of aluminum plate was detected at 10 m under water. According to the analysis of the experimental results, the maximum detection depth of an acousto-optic coupled interferometric hydrophone is 36m. Finally, a method of detecting the orientation and size of underwater targets by using laser source and acousto-optic coupled interferometric fiber-optic hydrophone array is presented, and its working principle is analyzed. The principle of using differential location algorithm and deconvolution algorithm to estimate the orientation and size of underwater target is introduced. Finally, the feasibility of this method is verified by numerical simulation of the detection system.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TB565.1

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相關(guān)期刊論文 前1條

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本文編號：2460847