水下近场噪声源高分辨定位方法研究

发布时间：2018-05-19 13:56

本文选题：近场噪声源定位 + 高分辨　；参考：《哈尔滨工程大学》2014年博士论文

【摘要】：舰艇自噪声会破坏自身的隐蔽性,为敌方的声呐提供检测及定位信息,还会对自身水声设备产生干扰。为提高舰艇的海上作战能力,必须有效的采取减振降噪措施。舰艇的体积较大,其辐射噪声源分布在不同部位,因此开展水下噪声源定位技术的研究,得到噪声源在舰艇上的空间分布,即可有针对性的进行噪声源的减振降噪工作。相比于远场源定位,近场定位可以更为精确的获得噪声源位置。然而,传统近场源定位算法的分辨力较低,容易产生空间上的混叠,对定位精度产生很大影响。本文基于线列阵,研究了水下近场噪声源高分辨定位方法。主要研究内容包括:1.针对噪声源中线谱信号的定位问题,提出了一种基于稀疏信号重构的近场源定位算法。通过约束稀疏信号的L1-范数构造优化问题,实现信源的定位。该算法可以通过估计噪声功率来自动选择折中参数,无需噪声的先验知识,满足了稀疏性与保真性的平衡。对于近场源定位,信源与各个阵元的时延差是方位角和距离的函数。如果对二维空间稀疏划分,计算量庞大,甚至不可接受。针对这个问题,本文利用对称阵元数据的组合构造了类远场协方差矩阵,该矩阵仅包含近场源方位角参数,进而将二维定位问题转化为两次一维参数估计问题,显著降低了近场源定位的计算量。仿真结果和水池试验结果验证了算法的有效性。2.相比于远场源定位,很多近场源定位算法将二维搜索转化为多个一维搜索,用以降低计算量。然而,这类算法为避免产生空间模糊现象,需要满足两个条件,即阵元间距需要设置为四分之一波长和估计的信源数不能大于阵元数的一半,在阵元数目不变的情况下,就存在很大的孔径损失问题。而阵列孔径是影响阵列分辨力和定位精度的重要因素。针对这个问题,提出了互素对称阵模型,有效的增加了阵元间距,使其不必受限于四分之一波长,扩大了阵列孔径。在互素对称阵模型下,通过重构一个特殊的高阶累积量矩阵,使其仅与信源方位角有关,然后采用MUSIC算法进行方位角估计,进而在每个估计方位上定位目标,无需额外的参数配对方法。此外,该方法在方位角和距离两个维度上都不会产生空间模糊现象。理论分析和仿真实验验证了该方法有效的提高了空间分辨力和定位精度。3.针对噪声源中的宽带连续谱信号的定位问题,研究了近场宽带源的定位方法,并提出了一种基于子空间正交原理的定位算法。该算法利用各个频带分量的信号子空间和参考频带分量的噪声子空间之间的正交性估计噪声源位置,并引入信号参考频率的阵列流形矢量的正交投影,用以减小噪声子空间估计误差对定位的影响,提高了空间分辨能力,并在低信噪比条件下有着较好的定位精度。该算法是投影子空间正交性测试算法在近场条件下的扩展,并充分利用了每个频带分量的信号子空间,解决了投影子空间正交性测试算法过于依赖参考频率信号子空间估计精度的问题。理论分析和仿真研究验证了该算法的有效性。
[Abstract]:The self noise of the ship will destroy its own concealment, provide detection and positioning information for the enemy sonar, and also interfere with its own underwater acoustic equipment. In order to improve the Naval Operational Capability of the ship, the vibration and noise reduction measures must be taken effectively. The volume of the ship is large and the radiation noise source is distributed in different parts, so the underwater noise source is set up. The research of bit technology obtains the spatial distribution of the noise source on the ship, which can reduce the noise and noise of the noise source. Compared with the far field source location, the near field location can get the location of the noise more accurately. However, the resolution of the traditional near field source localization algorithm is low, it is easy to produce the spatial aliasing and the positioning accuracy. Based on linear array, this paper studies the high resolution localization method of underwater near field noise sources. The main research contents include: 1. a near field source localization algorithm based on sparse signal reconstruction is proposed to locate the line spectrum signal in a noise source. The optimization problem is constructed by constraining the L1- norm of sparse signal to realize the source of the source. The algorithm can automatically select the eclectic parameters by estimating the noise power, without the prior knowledge of noise, which satisfies the balance between sparsity and authenticity. For the location of the near field source, the delay difference between the source and each element is a function of the azimuth and distance. If the two dimensional space is divided, the amount of calculation is huge and even unacceptable. In order to solve this problem, this paper uses the combination of symmetric matrix metadata to construct the covariance matrix of the class far field. This matrix only contains the azimuth parameters of the near field source, and then transforms the two-dimensional location problem into the two dimension parameter estimation problem, which significantly reduces the calculation of the near field source location. The simulation results and the pool test results verify the algorithm. The effectiveness of.2. is compared to the far field source location. Many near field source localization algorithms convert a two-dimensional search into a number of one-dimensional searches to reduce the amount of computation. However, this kind of algorithm needs to meet two conditions to avoid generating spatial ambiguity, that is, the interval between the array elements needs to be set to a length of four points and the number of the estimated sources cannot be larger than the number of elements. When the number of elements is constant, there is a large aperture loss problem, and the array aperture is an important factor affecting the array resolution and positioning accuracy. In this problem, a mutual symmetric matrix model is proposed, which can effectively increase the spacing of the array element, so that the array aperture is not limited to 1/4 wavelengths, and the aperture of the array is enlarged. By reconstructing a special high order cumulant matrix, it is only related to the azimuth of the source, and then the azimuth estimation is carried out by the MUSIC algorithm, and then the target is located on each estimated azimuth, and no additional parameter pairing is needed. In addition, this method will not produce the two dimensions in the azimuth and distance. Theoretical analysis and simulation experiments show that the method effectively improves the spatial resolution and positioning accuracy.3. for the localization of broadband continuous spectral signals in the noise source, studies the location method of the near field wideband source, and proposes a localization algorithm based on the subspace positive intersection principle. The orthogonality between the signal subspace of the band component and the noise subspace of the reference band component is used to estimate the location of the noise source, and the orthogonal projection of the array manifold vector of the signal reference frequency is introduced to reduce the influence of the noise subspace estimation error on the location, and the spatial resolution is improved, and it is better under the condition of low signal to noise ratio. The algorithm is the extension of the shadow space orthogonality test algorithm under the near field condition, and the signal subspace of each band component is fully utilized. The problem that the shadow space orthogonality test algorithm is too dependent on the precision of the subspace estimation of the reference frequency signal is solved. Validity.
【学位授予单位】：哈尔滨工程大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN911.7

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