Characteristics and Matching Method of Random Time-Variant Sound Channel in Shallow Sea

海洋声信道是随机时空变参、强多途径干扰。强噪声干扰的信道。本文第一篇用脉间相关法在厦门港浅海区对固定发射、接收的海洋声信道的随机时变性、信道起伏的功率谱等进行了初步的实验研究，同时还给出了信道时间平稳性的研究结果。对于一般的浅海声信道，时间平稳性在分钟量级；信道的相关时间长度Tc（脉间相关系数下降到0.7的时间）因况、距离的不同而差异很大，从数百毫秒至数分钟不等，文中给出了大致的Tc与海况、距离之依赖关系．由于海洋中的强多途干扰，信号经信道传播后产生了严重的畸变，以发射信号作为参考信号的匹配滤波器性能明显下降。本文第二篇首先采用解卷求信道响应法，在假定的浅海相干多途信道模型下，对修正匹配滤波器...Underwater sound channel is the one with random timespacial variables, severe multipath and high noise level interference. In part I, the time correlation and fluctuation power spectral density of random time-variant sound channel are studied experimentally by the use of the pulse-to-pulse correlation method. The variations of time stability and correlation time length to with sea state and distan...学位：理学硕士院系专业：海洋与环境学院海洋学系_海洋生物学学号：YL000027

A STUDY ON THE TIME-DOMAIN ATTENUATION CHARACTERISTICS of A SHALLOW SEA ACOUSTIC CHANNEL

研究了浅海声信道“时域衰落”与海况、波高、中心频率和作用距离的关系。结果表明：在相同海况下，波浪愈高，振幅起伏愈明显；在同样作用距离、深度下，中心频率20kHz是信道较好的传播频率，其振幅起伏小，自相关时间较长；在该声道中，作用距离在2000─2500M处振幅起伏最大。This paper studies the relations between "time-domain attenuation" and sea state or wave height, center Frequency or transmitting range.It is shown that (1) under similar sea state conditions, the higher the wave heights, the more serious the amplitude Fluctuations;(2) in the experimental sea area, the center Frequency 20 kHz was a better transmission Frequency, i.e.less amplitude Fluctuation and longer autocorrelation time;(3) the amplitude Fluctuation was maximum at a transmitting range of about 2 0002 500m in the experimental sea area.国家自然科学基