【作者】 付进；

【导师】 梁国龙；

【作者基本信息】 哈尔滨工程大学 ， 信号与信息处理， 2007， 博士

【摘要】 声学定位与导航技术是水下目标跟踪的核心技术,是海洋科学技术的重要组成部分。随着国家对海洋开发和海防建设的高度重视和巨大投入,声学定位与导航技术迎来了新的挑战和发展机遇。本文主要针对长基线声学定位中的信号处理若干关键技术进行研究,主要内容包括基于滤波和陷波组合应用的多通道自适应Notch滤波器组设计、基于信道多途抑制的时延估计技术、基于瞬时参数估计的信号检测技术等。单通道自适应Notch滤波器是提取单频信号的有效手段,但是当面临多个线谱成份时,其性能明显下降。本文分析了并联多通道和级联多通道自适应Notch滤波器的特性,提出了滤波和陷波功能组合使用的结构设计思想,设计和构建了多通道自适应Notch滤波/陷波器组,实现了多个单频信号的分别提取,并且避免了线谱干扰源引起的包络波动,从而提高了信号检测能力。目前,这种滤波器组结构设计已应用到工程实践当中,效果良好。时延估计误差是影响系统定位精度的重要因素之一。由于水下声信道的多途特性,接收点信号的幅度、相位、频率发生畸变,对时延估计精度产生严重影响。基于长基线系统的定位导航原理,本文分析了单阵元时延估计误差对系统定位精度的影响,论证了目标位于阵内不同位置时直达声和海面一次反射声相位差的变化规律,探讨了界面反射对系统定位精度影响的物理机理,并利用信号叠加特征提出了一套信道多途抑制新策略。该策略对提高系统检测“相消干涉”信号的能力和时延估计精度、改善声学定位系统性能有积极作用。参数估计理论在信号检测领域的成功应用极大地促进了信号检测技术的发展。瞬时频率方差检测器(VIFD)是一种典型的基于瞬时频率估计的信号检测器,它运算量小、性能稳健,成功解决了工程中检测多通道CW信号、抗通道串漏、抗混响干扰等技术问题,但该检测器只适用于载频恒定的信号。本文将VIFD的检测思想予以推广,利用LFM信号和HFM信号的频率特征,提出了两种新型“瞬时参数方差检测器”——调频斜率方差检测器(VFMSD)和周期斜率方差检测器(VPSD)。另外,针对其他信号形式,借用参数估计中的最小均方误差概念,设计了瞬时频率均方误差检测器(MSEIFD),提出了匹配滤波器(MF)与MSEIFD联合检测的思想,并进行了仿真验证。水声收发机是大型水声测控装备项目——SUNO系统的关键部件之一。本文基于SUNO系统的工作原理,设计并实现了一套多功能水声收发机,介绍了水声收发机的软、硬件设计思想和实施方案,并通过模拟器、湖试和海试试验对该系统进行了验证,同时利用消声水池定点测试和高精度定位标定系统分析了该套系统的定位精度。试验结果表明,SUNO系统性能可靠,定位精度满足系统指标要求。更多还原

【Abstract】 Acoustic navigation and positioning technologies are the kernels in the field of tracking underwater targets, are the key components of the Ocean technology. Along with the government attaching great importance and investing huge finance to the exploitation of the Ocean and the construction of the coast defenses, acoustic positioning and navigation technology is facing a new challenge and a good opportunity for development.Several key technologies of the signal processing in the long baseline acoustic positioning system were researched, including the design of multi-channel adaptive Notch filter based on the combined application of notch channel and filtering channel, the time delay estimation technology based on the anti-multi-path strategy, the signal detection technology based on instantaneous parameter estimation, and so on.Single-channel adaptive Notch filter is an effective means to extract single-frequency signal, but its performance often decreases significantly when faced with various spectral components. The characters of parallel multi-channel and serial multi-channel adaptive Notch filters were analyzed. A new kind of multi-channel adaptive Notch filter structure was designed by combining the filtering channel and notch channel. This structure can not only extract a number of different single-frequency signals, but also can avoid the envelope fluctuation caused by sinusoidal interferences, thus enhancing the signal detection capability. Recently, this structure has been used in practice and performed very well.Time-delay estimation error is one of the most important factors in the coastdown of positioning precision. Because of the underwater acoustic multi-path channel, the signal received was distorted in amplitude, phase and frequency, which would reduce the time-delay estimation precision. Based on the positioning and navigation property of long baseline system, the effect of single sensor’s time-delay estimation error on positioning precision was analyzed, the changing law of the phase difference between direct sound and surface reflected sound was demonstrated when the target lies in different location, the physical mechanism about interfacial reflection influence on positioning precision was researched, and a new signal processing measure was presented to overcome multi-path effect using the character of wrapped signals. The proposed anti-multi-path method can upgrade the offset interference signal detection ability and improve the time-delay estimation precision, so as to improve the capability and performance of underwater acoustic positioning systems.Parameter estimation theories have been applied on signal detection field successfully, which improved signal detection ability enormously. Variance-of-Instantaneous-Frequency Detector (VIFD) is a typical detector based on Instantaneous-Frequency estimation, which is robust and simple in operation. So far, VIFD has solved many technical problems, such as detecting multi-channel CW signal, restraining signal leakage among different channel and reverberation, etc. But VIFD is only suitable for the signal with constant carrier frequency. By means of promoting VIFD principle, two kinds of variance-instantaneous-parameter detector for HFM and LFM signal were proposed, which was called as Variance-of-Frequency-Modulation-Slope Detector (VFMSD) and Variance-of- Period-Slop Detector (VPSD). In addition, using the concept of minimum mean square error from parameter estimation theories, a new kind of detector in terms of other forms signal was put forward, called mean-square-error-of-Instantaneous-frequency Detector (MSEIFD), and an thought of combining the matched filter (MF) and the MSEIFD for detection was presented. The simulation result shows that the proposed detectors are effective.Acoustic transceiver is one of the key components of the SUNO system, which is a large measure and control equipment. According to the principle of SUNO system, a multi-function acoustic transceiver was designed and realized. The design thought of the software and hardware as well as the implementary scheme was introduced, and the capability of the system was verified by electricity simulator and trials in lake and sea. Meanwhile, positioning precision was analyzed by the means of fixed point Location in anechoic pool and trace calibration using High Precision Location System in Ocean. The result shows that SUNO system is robust and satisfying for use.更多还原