小波分析在惯性-多普勒声呐组合导航系统中的应用研究

在惯性-多普勒声呐组合导航系统中,多普勒声呐为惯性导航系统提供舰船的外部速度信息.组合导航系统的速度误差主要取决于多普勒声呐测速误差,多普勒声呐的性能将决定惯性导航系统的精度.由于舰船的摇摆、风浪、海水温度、多普勒声呐本身的缺陷等因素,使多普勒信号中不可避免地受到其噪声的影响.针对多普勒声呐信号的特点,采用小波变换对声呐信号进行多分辨力分析.利用Daubechies小波函数,采用阈值去噪的方法,能够在低信噪比的情况下准确地估计多普勒声呐的频移,从含有噪声的多普勒信号提取出原始信号.通过仿真实验表明,将小波分析应用于惯性-多普勒声呐速度组合导航系统中,能有效提高导航系统的速度精度.     

基于PXI总线的声呐接收机通用自动测试系统

本文基于PXI总线技术,NI虚拟仪器模块,搭建一种声呐接收机通用自动测试系统。给出了系统的硬件和软件设计方法、相关测试算法以及系统的实现方法。该自动测试系统能够客观、准确、快捷地对声呐接收机进行检测和故障定位,解决了声纳设备研制过程中缺少接收机通用测试设备的问题,提高了接收机的测试效率,避免了测试系统的重复开发,具有广阔的应用价值。     

基于反馈线性化的AFE变频器功率控制

提出了一种新的有源前端(Active Front End, AFE)变频器功率控制策略,仿真测试验证了基于该策略的AFE变频器具有交流侧电流畸变小、直流电压稳定、静态和动态性能好、能量可双向流动等优点。该策略基于多输入多输出非线性系统的反馈线性化理论和同步旋转坐标变换,将AFE变频器功率控制模型转化为线性、时不变的解耦系统,有利于控制系统的设计及实现。     

渔业科考船电力推进系统概述与分析

介绍了船舶推进的两种方式:常规机械直接推进与电力推进。指出电力推进系统在渔业科考船应用的优势。分析了电力推进系统中两种类型变频器的工作原理:DFE整流前端变频器和AFE整流前端变频器,并进行了性能比较。认为AFE系统体积重量更有优势,DFE系统具有成本优势。     

平台姿态与多普勒声呐深度测量的关系研究

多普勒声呐利用多普勒频移原理进行测速,其测流功能广泛应用于海洋资源的勘探开采、海洋环境、气象的监测等方面,其测量平台相对海底速度的功能应用于多种载体的导航.平台姿态对于多普勒声呐的使用和性能的发挥有较大的影响,主要研究平台的姿态角对于多普勒声呐的深度测量的影响,在考虑波束配制误差的条件下推导在有姿态角时的深度测量公式,对于提高多普勒声呐的深度测量精度具有较大的意义.     

基于粒子滤波的声呐图像目标跟踪算法研究

声呐图像目标跟踪技术在水下UUV作战系统中具有重要意义,由于水声环境复杂,噪声干扰严重,导致声呐目标跟踪效果欠佳。本文针对UUV声呐成像特点,首先给出一种改进的Curvelet变换图像增强方法,可以有效降低声呐图像噪声并在一定程度上增强目标图像的边缘。并此基础上,提出一种基于粒子滤波的声呐目标跟踪算法以获得更为准确的目标跟踪效果。仿真结果表明,相较于传统声呐目标跟踪,该方法具有更好的目标跟踪精度以及鲁棒性。     

一种船速检测系统在单级船闸中的设计与实现

通过对目前市场上测速技术的比选分析,设计了一套基于多普勒效应的雷达测速系统用于单级船闸的船舶测速,并经过在葛洲坝1号、2号、3号船闸现场实测分析,该测速系统可有效测量船舶进出单级船闸的船速信息,测量精度和范围能够满足目前船闸运行管理需要。     

一种嵌入式侧扫声呐系统的设计与实现

介绍一种基于嵌入式系统的侧扫声呐系统的设计与实现方法。嵌入式侧扫声呐由收发合置换能器、模拟信号处理单元、数字信号处理单元、通信与显控单元组成。基于嵌入式系统软硬件可裁剪,可移植性高等优点,使该侧扫声呐可灵活搭载在多种水下作业平台上,兼具了水下目标探测、海底地貌成像等功能,同时节约了空间和成本,具有较强的实用性。     

水下信息有效通信在船舶事故避障中的应用

现代船舶的发展方向是大型化和高速化,同时船舶的数量也在不断增加,单位海域面积内的船只数量不断增多。加上海上气候多变,船舶事故的数量不断上升。由于成本高、响应慢和体积大,传统的避障声呐系统已经无法满足现代船舶的需要。因此,急需一种成本低、精确度高、响应快和体积小的避障声呐系统来代替传统的避障声呐系统,以减少海上交通事故的发生。为此,本文将基于T型MEMS矢量水听器设计一种体积小、响应快和成本低的避障声呐系统。     

用于水下机器人的主动侧扫声呐图像预处理技术

分析了侧扫声呐接收机的噪声来源：自噪声和水体噪声,概括了它们影响声呐接收机的辐射路径;求出回波噪声的数字特征,在此基础上给出单扫描角度上声呐图像数据的递归最小二乘滤波算法,可提高水下机器人路径规划算法的实时l生。使用超小型远程操纵机器人（ROV）搭载SeaSprite声呐在船池中实验,对比给出预处理前后的声呐回波数据的还原图像,显示效果明显改善。     

Errata

正In the paper"Influence of Fouling Assemblage on the Corrosion Behaviour of Mild Steel in the Coastal Waters of The Gulf of Mannar,India"in Vol.12,No.4,Page:509,References were lost,and the two authors’biographies were identical.The correct text is shown below.We apologize to the authors and our readers for any inconvenience caused by the errors.     

Journal of Marine Science and Application 2014 Sum. Contents

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第34届海洋、离岸及极地工程国际会议(英文)

正St.John's,Newfoundland,Canada,May 31-June 5,2015 OMAE2015 is the ideal forum for researchers,engineers,managers,technicians and students from the scientific and industrial communities from around the world to: meet and present advances in technology and its scientific support;     

联合作战计划和执行系统

全球指挥控制系统(GCCS)实施当前美国海军网络中心战信息基础设施的联合计划网络。联合作战计划和执行系统(JOPES)支持GCCS实现联合计划。JOPES有两类计划：时间不限的精密预案计划生成作战计划、方案计划或职能计划；时间敏感的危机行动计划生成作战命令或战役方案。前者在和平时期创建的作战计划是后者的计划基础，加速应付危机的能力。     

Eastbound or westbound ?

In terms of equal sailing distances, where is the inflexion when ships depart from ports in the Asian Continent to New York via Suez and/or Panama？
The answer is China South Port Group （Hong Kong, Shenzhen and Guangzhou）.     

Recent progress on wave induced loading measurements in warships

Recent measurements of wave induced hull strain and flexure in RN warships are presented together with the derivation of the current design criteria for extreme hull girder bending loads. The history of the development of the shipboard instrumentation used is given and recent developments to improve the quality and ease of analysis of the data are described. An unexpectedly high transverse asymmetry in the longitudinal strains measured in destroyers is shown to be the result of a combination of vertical and lateral bending in oblique seas. Finally recent theoretical comparisons between the loading of Deep-Vee hulls and conventional UK rounded bilge hulls are presented which demonstrate the higher loading experienced by this type of hull form.     

桥梁防撞设施物理模型试验

物理模型试验是预报防撞设施所受撞击力及优化设计方案的主要方法之一。结合杭州湾大桥柔性防撞设施及东海大桥独立式防撞体设计方案,阐述了船—防撞体撞击试验的基本原理、方法、试验方案及相关试验结果。提出了柔性防撞系统的优化方案。试验结果表明,该方案经济有效,可供预报类似桥梁防撞设施撞击力时参考。     

印尼某电厂码头水工建筑物设计

印尼某电厂项目码头水工建筑物包括码头、防波堤和护岸等主要组成部分。在该项目水工建筑物的设计过程中,综合考虑当地的自然条件、施工能力和材料来源等因素,不断优化结构选型和结构断面。根据不同使用要求,护岸分别采用直立式和斜坡式2种结构型式,推荐的设计方案节省投资、施工方便,可供同类工程设计参考。     

Impact of regulation on the performances of long-distance transport services: A comparison of the different approaches in Sweden and Norway

Despite the many socio-economic similarities between Sweden and Norway, differences in jurisdiction, organisation, cooperation, and financing of long-distance passenger train and coach services have led to the development of four distinctively different ways of serving the markets. This paper describes how the train and coach markets have developed in the two countries, with emphasis on regulatory and industrial structure and a couple of performance variables.Looking at passenger rail, both countries separated infrastructure from operation over a decade ago. However, while Norwegian rail is characterised by an almost monopoly supplier, rail services in Sweden are partly decentralised to the responsibility of county authorities and are widely subjected to competitive tendering. The rest of the network is about to be opened up for on-the-track competition. Swedish Rail (SJ) has spent the last decades consolidating its core business (passenger rail) and sold out its other businesses. In contrast, the Norwegian state rail (NSB) has expanded its business to become a major bus operator and property owner, with extensions also into the Swedish market.The coach industry was more recently deregulated in both countries. The Swedish coach market is dominated by privately owned companies operating services to and from Stockholm. In Norway, state-owned NSB is a major coach operator on medium distance routes, and is also the largest partner of Nor-Way Bussekspress which totally dominates long-distance coach services. Further, the Norwegian coach market is characterised by cross-ownership and cooperation which has enabled an extensive route network which covers most of Norway.We find distinct differences in achievements in the two modes and in the two countries. Swedish rail services have succeeded in winning market shares and in renewing and developing both infrastructure and service levels to a greater extent than the Norwegian model. On the other hand, the Norwegian coach market seems to be more developed and efficient compared to its Swedish counterpart.The paper concludes with a discussion on the possible links between the different approaches and the performance observed, with the aim to stimulate further and more detailed research on some important issues.     

开放式数据挖掘系统模型

目前国内已经出现了少量的数据挖掘相关产品。国内数据挖掘软件无论从数量还是质量上比较，都与国外软件存在着较大的差距。随着数据仓库技术的普及，数据挖掘应用的需求越来越强烈，如何缩短这种差距，研发数据挖掘软件产品成为国内业界的一个重要问题。通过引用目前国际通用数据挖掘标准技术来构建开放式的数据挖掘系统模型，该系统模型从可扩展性、可重用性、易用性等方面得到了加强。