New Scientific Underwater Cable System Tokai-SCANNER for Underwater Geophysical Monitoring Utilizing a Decommissioned Optical Underwater Telecommunication Cable

We have developed a new cost-effective scientific underwater cable system named Tokai Submarine Cabled Network Observatory for Nowcast of Earthquake Recurrences (Tokai-SCANNER) using a decommissioned optical underwater telecommunication cable. We have used this cable in two ways simultaneously: 1) to construct an ocean-bottom observatory at the end of the cable, and 2) to use the cable as a long emitting antenna to sense electromagnetic properties of the Earth's crust. We have also developed a new time-synchronization system that sends a one-pulse-per-second (1PPS) signal and NMEA data to underwater sensors. To vary the supply voltage and current to the observatory and to emit a low-frequency electromagnetic field around the underwater cable, we have also developed an underwater power unit that has a wide input voltage and current range. Tokai-SCANNER has been functioning since April 2007.      

水下全自动显微成像仪

介绍了水下全自动显微成像仪的原理、关键设计和现场试验情况.该仪器有效地解决了水中采样技术,可用于1～100μm悬浮颗粒的现场图像拍摄,工作水深达100 m.利用该仪器拍摄到了现场悬浮颗粒图像,利用这些图像可以分析悬沙颗粒分布,同时也可以检测浮游生物,研究赤潮.     

Underwater acoustic networks

With the advances in acoustic modem technology that enabled high-rate reliable communications, current research focuses on communication between various remote instruments within a network environment. Underwater acoustic (UWA) networks are generally formed by acoustically connected ocean-bottom sensors, autonomous underwater vehicles, and a surface station, which provides a link to an on-shore control center. While many applications require long-term monitoring of the deployment area, the battery-powered network nodes limit the lifetime of UWA networks. In addition, shallow-water acoustic channel characteristics, such as low available bandwidth, highly varying multipath, and large propagation delays, restrict the efficiency of UWA networks. Within such an environment, designing an UWA network that maximizes throughput and reliability while minimizing the power consumption becomes a very difficult task. The goal of this paper is to survey the existing network technology and its applicability to underwater acoustic channels. In addition, we present a shallow-water acoustic network example and outline some future research directions     

基于水下预置系统的深远海水下作战体系

通过分析强敌对我不断加大防范遏制力度,且水下装备技术朝信息化、智能化方向的快速发展, 提出构建基于水下预置系统的深远海水下作战能力对根本扭转我海上战略安全形势、在深远海有效拒止强敌的重大意义和难得机遇。在此基础上,进一步分析了基于水下预置系统的深远海水下作战体系担负的主要作战任务、基本构成及能力优势。选取东海方向大规模军事行动中,位第二岛链内外实施拒止作战作为典型场景,初步探索了体系基本兵力部署及总体运用,并对未来开展体系建设提出了思考建议。     

智能水下机器人水声精确定位技术的研究

讨论了智能水下机器人水声定位技术,给出系统的组成、定位教学模型。论述了提高定位精度措施,最后给出试验测量结果。     

Self-Tuning Underwater Image Restoration

A self-tuning image restoration filter based on a simplified version of the Jaffe-McGlamery underwater image formation model is presented. Optimal values of the filter parameters are estimated automatically for each individual image by optimizing a quality criterion based on a global contrast measure. The simplified model is ideally suitable for diffuse-light imaging with limited backscatter, but qualitative tests show good performance in a variety of imaging conditions. In addition, quantitative tests with a large number of frames from six real mission videos indicate a substantial performance improvement when restoration is used as a preprocessor for a classifier detecting man-made objects in unconstrained subsea videos     

多波束系统搜救水下目标的探测深度计算

针对多波束测深系统种类、探测模式等因素影响水下目标搜索效能的问题,提出了一种面向水下目标搜索的多波束系统探测深度计算方法。分别对多波束系统等角与等距模式进行探讨,考虑波束间重叠角的影响,由多波束横向分辨率计算公式推导了 2 种模式的探测深度公式,并将不同波束角度的探测深度进行计算。经过结果比对,总结出等角模式搜索水下目标的探测能力要优于等距模式。最后结合算例,得出多波束探测能力与目标尺寸、海水深度、波束开角有关。