【作者】 杨娟；

【导师】 惠俊英；

【作者基本信息】 哈尔滨工程大学 ， 水声工程， 2007， 博士

【摘要】 水下被动定位技术一直以来是人们关注的焦点。随着对水下声场研究的进一步深入,出现了以声场分析为基础的匹配场被动定位技术。TMA技术则通过对一段时间内数据的综合利用,来对目标运动状态进行分析。它们是被动定位技术中新发展起来的两个热点。本文以这两种方法为出发点,通过分析低频矢量声场,探索适用于单水听器(矢量水听器)的被动定位新方法。文中首先根据射线理论建立了低频矢量声场的模型,给出了传播损失曲线,并与波动理论结果进行了比较,说明射线理论在近距离是波动理论的良好近似。通过对声压、振速的干涉现象进行分析,说明了声压和水平振速符合一致的传播规律。之后,以干涉声场分析为基础,分析了水面舰船干涉条纹的双曲线簇分布规律,目标运动的状态(包括速度、深度和水平距离)将决定双曲线簇的形状。分别讨论了目标运动在深海和浅海状态下,干涉条纹的不同特点。Hough变换是一种用于边缘检测的图像处理手段,在水声信号处理中已被用来与时频分析手段联合起来对信号进行估计,例如Wigner-Hough变换利用对直线的Hough变换来估计线性调频信号斜率等。针对干涉谱双曲线型条纹,本文利用Hough变换提取双曲线参数,可以分析目标的航速、航深和最近通过距离。然后,文章从理论上分析了干涉谱中频率周期的物理意义,给出了测量干涉频率周期对目标定位的方法。讨论了干涉谱分析在水声信号处理中应用的优缺点,利用干涉谱来分析目标尾流干扰的频段,消除强线谱引起的窄带干扰等,对水下靶场等近距离目标被动探测有一定的应用价值。水下高速运动目标的被动跟踪系统,目前己步入实际系统的研制阶段。被动跟踪方式的靶场测控技术,无需在目标上加装合作信标,因而能够大大提高试验效率。水下高速运动目标的被动跟踪需要面临的主要挑战是高速运动目标的多普勒效应和水下信道的多途效应。由于目标高速运动,产生的多普勒效应,使得多普勒补偿成为必需,然而由于水下高速运动目标的多普勒系数很大,分析多普勒变化率成为关键。文章首先推导并分析了二阶多普勒系数及其对一阶补偿的影响,又对二阶多普勒系数估计的信噪比条件进行了分析,之后分析了高速目标运动引起各途径声线之间的多普勒系数差。在此基础上克服高速运动目标多普勒效应的影响。针对被动跟踪系统,为了获得高精度解,需要采用长基线定位手段。然而,传统的长基线定位在不知道目标初始位置的情况下,需要通过大量的计算来进行关联,对于高速运动目标,同时还要进行多普勒补偿,这就进一步增加了计算的负担。根据对本跟踪系统的阵形分析,提出了利用长基线和虚元短基线联合进行被动目标跟踪的方案。既有效地减少了计算量,又不需要增加系统设计成本,达到了最优的设计目的。在近程高精度跟踪系统中,多途效应成为影响定位精度的主要因素,根据本系统用于测量近程高速变深运动目标的特点,设计了被动目标跟踪的抗多途专家系统,能够有效减小相关峰的误判概率,从而保证了被动跟踪系统对水下高速运动目标的运动轨迹可以进行有效测量。更多还原

【Abstract】 Passive detection and location in underwater acoustic has always been the focus of researchers. As the further research on the underwater acoustic field, the matched field passive source location is proposed. While TMA (target motion analysis) make full use of the data during a time period to estimate the state of the moving target. They are the two new hotspots in passive location researching field. According to these two technology, this dissertation explores the new way for passive source location which can be used in single (vector) hydrophone based on the analysis on the underwater acoustic vector field modeling.The model of acoustic vector field at low frequency based on the ray theory is established first. Then the transmission loss curves between ray theory and mode theory are compared, which show that the ray model is a good approximation to the mode theory in near distance. And then the interference phenomenon of pressure and velocity is discussed, which shows that the pressure and the horizontal velocity have the same interference pattern. Based on the analysis of the acoustic interference phenomenon, this dessertaion deduced that the interference pattern is hyperbola cluster. The target motion state (speed, depth and the nearest distance) will determine the shape of these hyperbola clusters. The different affect of target traveling in shallow water and deep water to the interference pattern is discussed. Hough transform is a usual method for the image edge detection. It has been used in the underwater acoustic field for estimation combined with time-frequency analysis, exemplified by estimate the frequency slope of the LFM signal with wigner-Hough transform. This dissertation uses the Hough transform to distill the parameter of the hyperbola curve to estimate the target state (speed, depth and the nearest distance) .Then, this dissertation analyzes physical meaning of the interference period theoretically and discusses the location methods. The application of the interference spectrum in underwater acoustic is also discussed. It can be used to eliminate the wake effect of the moving target and the strong instantaneous narrowband disturb which could have some practical value in the short distance detection. The passive tracking system for underwater high speed target has already stepped into the realizing stage. Passive ranging technology needs no informations of the target signal form, which would improve naval shooting trial efficiency greatly.The main obstacles for the passive tracking system are the Doppler effect and multipath effect.The Doppler compensation is necessary for the high speed target tracking because of the high Doppler coefficient in underwater acoustic environment.The second order Doppler coefficient is deduced and the affect to the first order Doppler compensation is discussed.And then this dissertation analyzes the Doppler coefficient difference between the different acoustic ray caused by the high speed moving target.The purpose of all these analysis is to overcome the Doppler effect.To obtain high estimation precision, the long baseline system is needed. However, the traditional long baseline positioning cost expensive computation in absence of target initial position,which will be even worse for the high speed target because of Doppler compensation.According to the passive tracking system composing model , a noval method is presented that the long baseline associated with virtual short baseline.Using this method, the computation burden is lightened with no increasing of system facility.To overcome the multipath effect, an expert system for the short range tracing target is designed,which can reduce the time delay estimation error in multi- correlation peaks.This expert system guarantees the effectiveness of the passive tracing measurements for the high speed target.更多还原