数字式主动声呐研制的初步探索

首先介绍数字式主动声呐的优点及实现上的特殊困难．采用时间相关积累信号处理方法，可以克服海洋背景噪声和船只自噪声的干扰，并具有强烈的抗起伏性能．在垂直向下探测或短距离、高频探测等特殊条件下，依混响的衰减规律，由微机组成精确的灵敏度时间控制网络，可以抑制混响的影响，并大大地简化了目标识别的难题．回声测深仪、垂直探鱼仪及本文介绍的浅海航行暗礁障碍探测仪的研制和海上实验，说明了这个结论．     

海底三维可视化技术及应用

海底地形地貌能表现海洋世界重要的空间信息,也是常规光学和电磁手段难以探测的水下区域。应用侧扫声纳技术可以反演海底地貌,同时多波束测深技术得到的水深数据重建数字水深模型,二者结合创建三维海底空间景观。利用海洋探测技术和三维可视化技术进行海底地形地貌三维仿真和分析,并对其应用进行探讨。     

Drowned shelf-edge deltas, barrier islands and related features along the outer continental shelf north of the head of De Soto Canyon, NE Gulf of Mexico

Four drowned shelf-edge delta complexes, two drowned shelf deltas, three drowned barrier islands, large areas of “hardground”, and fields of bedforms on the mid and outer continental shelf and uppermost slope north of the head of De Soto Canyon, NE Gulf of Mexico were mapped with high-resolution multibeam echosounder. Deltas formed not during the last eustatic low stand, but during one or more interstadials when eustatic sea levels were only 60 to 80 m below present sea level. The barrier islands and deltas must have been cemented prior to rapid falls of eustatic sea level that occurred during global glaciations. Cementation is necessary to have preserved the barrier islands from erosion and subsequent destruction by the rapid sea-level rise during the last deglaciation. The preservation of the relict bathymetry is so good that features that superficially resemble trough blowouts are found in association with one of the relict barrier islands. Asymmetric bedforms on the midshelf in water depths of 50 to 60 m indicate transport directions to the SW but asymmetric bedforms in water depths of the upper slope between 100 and 120 m on the S and SE flanks of the drowned shelf-edge deltas indicate a different current direction, a separate flow that is a continuation of a SW-flowing current that was previously found on the upper slope off NW Florida.     

Mapping Seabed Geology by Ground-Truthed Textural Image/Neural Network Classification of Acoustic Backscatter Mosaics

We present a novel, automated method for seabed classification based on shallow water backscatter mosaics from Sydney Harbour. Our approach compares the results between two different methods of image feature extraction when combined with artificial neural networks. The association of image textures with seabed geology is used to train the artificial neural networks to recognise the variability of textural attributes for three seabed classes comprising mud, sand and gravel. After network training, we classify unknown portions of the backscatter mosaic with a success rate ranging from 77% to 92%. Our results suggest that the computationally fast grey-level co-occurrence iteration algorithm holds promise for benthic habitat mapping in space and time, leading to real-time data analysis at sea.     

Long-term development and current status of the Barcelona continental shelf: A source-to-sink approach

The Barcelona continental shelf, off the city of Barcelona (NE Spain), is a relatively narrow canyon-bounded shelf in the northwestern Mediterranean Sea. Three medium-size rivers (Tordera, Besós and Llobregat) and several ephemeral rivulets flow into this margin. Two main domains have been recognized in the Barcelona shelf: (i) a modern, river-influenced area, and (ii) a relict, sediment depleted area, both affected by a variety of human impacts. A detailed geomorphologic study based on multibeam bathymetry and backscatter data, high resolution seismic profiles, and surface sediment samples allowed mapping and interpreting the main distinctive seafloor features on the Barcelona shelf. Modern sedimentary features reveal that the Llobregat River is the main sediment source of the Barcelona prodeltaic shelf. High-discharge fluvial events result in the formation of suspended sediment plumes and sediment waves on the shelf floor. Relict (late Pleistocene–Holocene) sedimentary features reflect that an important shift occurred in the seashore direction between MIS 4 and MIS 2, and that recent neotectonic reactivation has created a set of seafloor faults. The Barcelona inner and middle shelf is severely impacted by anthropogenic activities such as the enlargement works of the Port of Barcelona, sewage pipes, dredging, anchoring and trawling.     

高分辨率测深侧扫声纳

文中介绍了由中国科学院声学研究所和美国亚迪技术开发（上海）有限公司联合设计和制造的高分辨率测深侧扫声纳,它能够同时获得高分辨率的海底地形和地貌。该声纳由电子分机和分别安装在载体左右两侧的两条声纳阵组成,最大工作水深6000m。声纳阵由一条发射线阵和10条间距为λ／2的接收线阵组成,λ为声波波长,其中8条线阵接收声信号,两边的两条为哑元。声纳的多子阵海底自动检测-子空间拟合信号处理方法能克服水声信道多途和复杂海底的影响,正确检测到海底的直达回波。2003年11月和2004年7月,声纳在中国浙江千岛湖进行两次长时间的湖试,获得了高分辨率湖底等深线图和地貌图,正确检测出湖底边长为0．5m立方体目标的高度。     

一种基于MATLAB的声呐条带图像自动拼接算法

准确地实现侧扫声呐条带的拼接对于了解海底地形、提高对海床地物反映的准确度起着重要的作用,而相邻条带的配准是声呐条带拼接的重要前提.MATLAB以其强大的矩阵运算功能及具有丰富的图像处理函数等特点,在图像处理方面占据明显的优势.文中利用MATLAB的IPT工具箱实现了基于互信息方法的声呐条带图像的自动快速配准,通过实验验证了该配准方法的有效性.并用小波变换方法对配准好的条带图像进行融合,实现声呐条带图像的有效拼接和镶嵌.     

Shelf habitat distribution as a legacy of Late Quaternary marine transgressions: A case study from a tropical carbonate province

The legacy of multiple marine transgressions is preserved in a complex morphology of ridges, mounds and reefs on the Carnarvon continental shelf, Western Australia. High-resolution multibeam sonar mapping, underwater photography and sampling across a 280 km² area seaward of the Ningaloo Coast World Heritage Area shows that these raised features provide hardground habitat for modern coral and sponge communities. Prominent among these features is a 20 m high and 15 km long shore-parallel ridge at 60 m water depth. This ridge preserves the largely unaltered form of a fringing reef and is interpreted as the predecessor to modern Ningaloo Reef. Landward of the drowned reef, the inner shelf is covered by hundreds of mounds (bommies) up to 5 m high and linear ridges up to 1.5 km long and 16 m high. The ridges are uniformly oriented to the north-northeast and several converge at their landward limit. On the basis of their shape and alignment, these ridges are interpreted as relict long-walled parabolic dunes. Their preservation is attributed to cementation of calcareous sands to form aeolianite, prior to the post-glacial marine transgression. Some dune ridges abut areas of reef that rise to sea level and are highly irregular in outline but maintain a broad shore-parallel trend. These are tentatively interpreted as Last Interglacial in age. The mid-shelf and outer shelf are mostly sediment covered with relatively low densities of epibenthic biota and have patches of low-profile ridges that may also be relict reef shorelines. An evolutionary model for the Carnarvon shelf is proposed that relates the formation of drowned fringing reefs and aeolian dunes to Late Quaternary eustatic sea level.     

侧扫声呐系统在荣成海流能电站示范工程中的应用

介绍了侧扫声呐系统在荣成海流能电站示范工程中的应用,对侧扫声呐系统的工作原理、图谱的特点及影响图谱影像质量的因素进行了分析,基于海流能示范工程扫测图谱影像进行了数据处理与特征提取,并将地貌分类成果应用到设计施工中取得了较好的效果;对工程应用中遇到的问题进行了总结。     

综合测量船电磁兼容技术研究

电子、电气设备的广泛应用,使得测量船的电磁环境越来越复杂,尤其是安装了多种声学设备的综合调查船,在设计建造的开始就必须引入电磁兼容以求得最高效能比.以某综合调查船为背景,分析了主要干扰源、耦合路径,提出了相应的处理措施.