Underwater acoustic applications

由于声波在水中的吸收率低，因此经常用于各种海洋变量的遥感、海底沉积物分类、海洋测深、鱼类种群评估、水声通信、导航定位。大多数这些应用需要很好地理解水声信道和复杂的信号压缩、传输和接收算法。在高混响、时变的水下信道中，声传输通常需要一个结合自适应声波束形成和跟踪的自适应接收机。这在浅水传输中尤为重要。精确的声导航和多波束声测深需要有效的声射线追踪算法。与声传感相关的大量数据需要有效的压缩才能传输或存储。任何声学传感系统的实际设计都必须解决这些问题。提出的研究将认识到所有这些问题，但将集中研究用于水下平台（如海底爬行器和各种水下航行器）精确导航和定位的新型声学方法。这种平台越来越多地用于海洋研究、海底检查和海洋观测系统，如加拿大海王星计划和其他几个计划。将开发新的传输和信号处理方法，以达到目前可用系统无法达到的精度。要解决的具体应用还包括测量板块运动，其中需要的精度以毫米为单位，以公里为单位。要达到如此高的精确度，需要采用新的测量方法。另一个研究领域将集中在使用深度测深仪和侧视声纳进行海底表征和分类的新方法上。海底类型及其地形的测绘对渔业、鱼类资源评估和其他海洋勘探领域具有重要意义。

Due to their low absorption in water, acoustic waves are frequently used for remote sensing of various oceanographic variables, bottom sediment classification, ocean bathymetry, fish stock assessment, underwater acoustic communication, navigation and positioning. Most of these applications require good understanding of underwater acoustic channels and sophisticated algorithms for signal compression, transmission and reception. Acoustic transmissions in highly reverberant, time-varying underwater channels often require an adaptive receiver combined with adaptive acoustic beam forming and tracking. This is particularly relevant in shallow water transmissions. Efficient acoustic ray tracing algorithms are needed for precise acoustic navigation and multi-beam acoustic bathymetry. The large amounts of data associated with acoustic sensing require efficient compression for transmission or storage. Any practical design of acoustic sensing systems must address these problems. The proposed research will recognize all these problems but it will concentrate on novel acoustic methods for precise navigation and positioning of underwater platforms such as bottom crawlers and various underwater vehicles. Such platforms are more and more frequently used for ocean research, bottom inspection and in ocean observing system such as planned by Neptune Canada program and several others. New methods for transmission and signal processing will be developed to achieve precisions not attainable by presently available systems. Specific applications to be addressed include also measurements of plate movements where required precision is in order of millimeters over distances in order of kilometers. Achieving such an extraordinary accuracy require new approaches to such measurements. Another area of research will concentrate on new methods for bottom characterization and classification using depth sounders and side-looking sonars. The mapping of bottom type and its topography is important for fisheries, fish stock assessment and other area of ocean exploration.