【作者】 魏建新；

【导师】 方尔正；

【作者基本信息】 哈尔滨工程大学 ， 水声工程， 2009， 硕士

【摘要】 随着减振降噪技术的发展,水下大型结构的辐射噪声越来越低,使得常规的噪声测量设备不能满足测量要求。声纳阵列可以获得较高的测量增益,可以实现对较低辐射噪声的目标进行测量。然而由于线阵阵元多,体积庞大,因此价格昂贵且布放回收不方便。被动合成孔径技术可以以较少的阵元获得符合要求的波束宽度和增益,且费用低、灵活性好,为低噪声测量开辟了一条新途径。论文回顾了常规波束形成方法的原理,讨论了被动合成孔径的工作机理,推导了数学模型,通过计算机仿真,得到了被动合成孔径波束形成技术的性能及影响因素。给出了时间相干性和拖曳速度等参数不同条件下PSAS(Passive Synthetic Aperture Sonar)的输出结果。文中描述了水下目标噪声测量的基本要求,通过对噪声测量系统对声纳阵列基本要求进行分析,得到了能够应用于噪声测量的PSAS阵列参数。对FFTSA(Fast Fourier transformsynthetic aperture)算法和ETAM(Extended towed array measurements)算法进行理论推导和计算,给出了被动合成孔径用于噪声测量的设计原则。通过与常规波束形成方法的对比,得到这样的结论:采用被动合成孔径算法,可以获得长阵具有的阵增益和方位分辨力,可以降低工程实施难度,适合低噪声目标的辐射噪声测量,有很好的应用前景。更多还原

【Abstract】 Along with the antivibration noise reduction technology’s development, the radiated noise of the submarine large-scale structure is getting lower, so it is impossible to satisfy the metrical request by the conventional noise measurement equipment. The sonar array may obtains higher gain, and may measures the lower radiated noise. However, the linear array has many elements and big volume, therefore it is expensive, and reclaims it discommodiously after deployed.The passive synthetic aperture technology can obtains beam-forming’s width and gain perfectly by less elements, also the price is low and the flexibility is good, which opens a new way for the low noise measurement.The paper reviews the principle of convention beam-forming method. Discusses the mechanism of passive synthetic aperture, infers the mathematical model, educes the performance and influencing factor of passive synthetic aperture beam-forming technology by the computer simulation. The paper also gives the output of PSAS under the conditions bases on different parameters of time coherence and the hauling velocity.The paper describes the essential requirements of measure the underwater noise, and analyses the requirements through the noise measurement system to the sonar array, obtains the array parameter of PSAS what is able to apply in the noise measurement. Calculates the algorithms of FFTSA (Fast Fourier transform synthetic aperture) and ETAM (Extended towed array measurements), shows the principle for designing the passive synthetic aperture that uses in the noise measurement. Compares with conventional beam-forming, the paper shows some conclusions: uses the synthetic aperture algorithm, may obtains the array gain and azimuth resolution of large array, may reduces the difficulties of the project, may meet the requirement for measuring the low radiated noise target, has provided the reference for the following research.更多还原