深水网箱中鱼群监测仪发射信号源的设计

深水网箱养殖是目前国内外海水鱼类养殖业可持续发展的总体趋势和必然要求。网箱中必须要配置实时监测水下鱼群动态的鱼群状态监测仪。为了满足监测仪多种频率和脉宽选择的需要，提出了一种基于单片微机AT89C51和RAM／IO扩展器8155产生连续多路脉宽、频率可调信号源的方案。实验结果表明该方案简单易行，准确可靠，容易推广。     

HDPE深水网箱抗风浪流性能的海区验证试验

对HDPE深水网箱2000～2004年间的抗风浪流性能进行了海区验证试验.通过对HDPE深水网箱扶栏、框架、网具以及固泊系统受损率的统计,根据扶栏、框架、网具以及固泊系统在整个深水网系统中的重要程度,分别给予一定的权重统计出深水网箱的整体受损率,能比较客观地反映深水网箱的抗风浪流性能.海区验证试验结果表明,HDPE深水网箱抗风力达35 m/s、抗浪高6 m、抗流速1.0 m/s,与其设计参数基本相同.同时,为了增加HDPE深水网箱的抗风浪流性能,建议扶手管从110 mm改为125 mm、主浮管从250 mm改为300 mm、扶栏高度从1 m降低为0.8 m或0.6 m.风力主要影响扶栏系统,流速主要影响网具系统,而波浪对HDPE圆形浮式深水网箱的框架、网具、固泊系统以及网箱整体结构均有明显影响.     

机载小型SAR研发与海洋溢油监测试验研究

基于海上溢油监测需求,自主研发了小型合成孔径雷达(SAR),并基于机载平台开展海上监测试验,进行应用测试。研发的小型SAR工作在C波段,极化方式为VV,质量24kg,可搭载于有人或无人飞行器,对较大面积海域进行实时连续成像,在获取设定分辨率的SAR实时影像的同时,完整记录原始回波信息,可进一步地面处理生成精细影像。2015年8—9月在山东烟台威海近海海域开展了机载小型SAR海洋监测试验,获取了海上目标包括平台、船只、浮筏和海上疑似油膜现象的SAR影像,成像良好。海上试验研究表明,小型SAR可以提供高质量的海面SAR影像数据,为海面目标及油膜的实时监测提供有利支持。     

基于5G通信技术的网箱养殖在线监测系统设计

针对目前网箱养殖监测技术在数据传输的实时性、连续性以及高带宽影像传输的稳定性等方面存在的不足,本文提出了一种新型的基于5G通信技术的网箱养殖在线监测系统设计方案。本方案采用光伏阵列、蓄电池组和太阳能控制器组合的方式为整个系统提供电源支持,岸基控制系统通过水密电缆与水下监测设备建立连接,并将监测数据和高清视频经5G数据传输系统上传至数据监测中心,同时手机终端App同步在线展示。该系统在海南省陵水黎族自治县清水湾附近网箱养殖海域成功布放和试运行,实现了对海水温度、盐度、深度、溶解氧等常规水文生态要素和水下高清视频的连续、实时、在线监测,这对于网箱养殖的可测、可视、可控具有重要的科学意义和应用价值。     

声相关海流剖面(ACCP)测量的流速估值方法

声相关海流剖面（ACCP）测量技术对水体回波信号进行空间相关处理来估计流速值，与声学多普勒海流剖面仪（ADCP）相比ACCP的工作频工，更适合深海测流应用，ACCP测量系统对回波信号进行时空相关处理，根据相关函数的位置来估计被测水团的流速值，ACCP从信号中提取流速值要运用参数估计技术，本文介绍了采用极大似然法和最小二乘法进行流速参数的处理方法，给出一些典型流速情形的数值计算结果。     

网格锚定单体碟形网箱的水动力特性研究

目前碟形网箱在我国并未得到广泛的推广应用,但其良好的抗流抗变形能力和可沉降特点使其在大风大浪水流湍急的深海水域有着不可替代的作用。如能在深水碟形网箱的基础上,开发出具有自主知识产权的深水网箱,必将对我国的养殖业产生重大的影响。本文基于凝集参数法,利用Orca Flex软件建立网格锚定的深水碟形网箱模型,并进行了多海况下的数值计算。结果表明,波流联合作用下,对锚绳张力影响最大的为海流流速,其次为波高,周期对张力的影响并不明显;锚绳最大张力并非出现在入射波与流速同向的情况下,而是发生在两者存在某一夹角时;浮环最大倾角随流速和波高线性增大,随着波浪周期增大而减小;此外,下沉能明显改善网箱系统和锚绳的受力。     

多桩桶基平台沉贯过程监测系统研究

为了解决海上恶劣环境下过程参数实时检测的困难,对海上桶基采油平台沉贯过程监测系统进行了研究。提出了主动利用潮汐、浪涌信息对沉深数据进行滤波处理的方法和单一桶桩的沉深和平台倾角信息计算其他多桩沉深的方法。直接利用浪涌检测信息,提高了沉深监测精度和实时性;采用一桶沉深与倾角数据计算多桶沉深的方法,节省了测深传感器,简化系统结构,降低系统成本。实验证明,该系统具有响应速度快,检测精度高,实时性强等特点。     

基于GPRS/GPS的海上移动目标监测系统设计

提出了一种运用GPRS/GPS技术实现海上移动目标监控及位置测量的系统设计方案,介绍了监测系统的结构组成及工作原理,阐述了系统嵌入式平台搭建、GPS定位数据获取以及利用GPRS无线通信技术实现远距离数据传输的方案设计与实现,并提出了对海上移动目标异常状况的判断和处理方法。该方案能够满足海上移动目标远程监控及位置测量的要求,并可以有效地降低成本,便于在实际中进行推广和应用。     

数字存储记录器

一、引言记录器是鱼群探测仪中的主要终端显示设备。特别是在垂直鱼探仪中,几乎是必不可少的。人们用它来记录目标回波、判别鱼群种类、估计目标的大小及有无捕捞价值等。并在长期的使用过程中,通过不断地改进,在技术上也有了很大发展,从干式记录到湿式记录,以及为了提高记录速度由单笔发展到多笔记录方式等等。现在出现了一个新的动向:用示波管记录器取代机械记录式的记录器。它的出现必将引起人们广泛的兴     

海上风电支腿船单桩沉桩技术

目前我国海上风电开发已经进入了规模化、商业化的发展阶段,海上风电的建设呈现由近海到远海,由浅水到深水的趋势。在响水、东台海上风电场中,均采用稳桩平台定位、起重船吊打工艺。文章结合某海上风电工程深水条件下大直径单桩沉桩施工情况,介绍自带定位抱桩器的1000t支腿起重船沉桩施工技术。     

ECHOBASE—A portable geographic fishery research database system

A geographic fishery research database system (GFRDBS), called ECHOBASE, for storing and management of data on pelagic fish resources from acoustic surveys and catch samples, combined with environmental data in a geographic context, has been developed. The system constitutes a portable and inexpensive yet powerful tool for fishery research and environmental monitoring and provides on‐board data processing and mapping capabilities.

Data are acquired from an echosounder, echo signal processor, environmental profiler (CTD probe), and Global Positioning System (GPS) receiver. The electronic digitized maps (based on C‐MAP public format files) provide active on‐screen nautical charts.

The basic GFRDBS platform is a portable PC 486 machine, which is used as an on‐board data acquisition and processing tool running under MS Windows 3.1 operating environment. The system is designed around the Borland's PARADOX package, which provides a relational database for managing acoustic, catch, and environmental data. The ECHOBASE programs were written in Borland C ++ language as a Windows application.     

联合小波和NLM滤波的侧扫声纳回波信号降噪

为进一步降低侧扫声纳回波信号中非高斯分布的乘性噪声,获取更佳效果的侧扫声纳图像,提出了一种利用小波和NLM(nonlocal means)滤波的组合降噪方法.首先采用同态变换将侧扫声纳回波ping信号中的乘性噪声转换为加性噪声,然后利用小波阈值和NLM滤波对侧扫声纳每ping回波数据实施降噪处理,最后经过小波反变换和指...     

海洋测深中垂直分置海底混响信号的仿真分析

海洋测深中,海底混响信号是测深仪回波信号检测的主要内容。测深仪通常采用信号的相关处理方法对其进行检测,因此在设计测深仪的回波处理单元时,系统地分析海底混响信号的相关特性就显得尤为重要,对混响信号仿真是分析其特性的有效手段。基于单元散射理论,依据海底散射系数的空间相关半径划分散射单元,给出垂直分置海底混响信号的仿真方法。研究结果表明,该模型物理意义明确,计算简单。仿真得到的海底混响信号具有非常好的空间相关性和时间自相关性,与实测的海底混响信号相符,可用于对混响场特性的分析,改善测深仪的设计,从而有效提高测深仪的测量精度。     

A comparative analysis of in situ methods for directly measuring the acoustic target strength of individual fish

In recent years, acoustic techniques have been used extensively to monitor and quantify fish stocks remotely. One of the parameters that is often measured is the target strength of the individual fish in the population. To obtain the target strength of a fish from its acoustic echo, the effect of the transducer beam-pattern factor must be removed from the echo amplitude. This paper discusses a number of different approaches for directly estimating the beam-pattern factor for an individual fish target. The effects of noise and interfering signals on the various estimation techniques are investigated. Expressions are derived for the bias and variance in the estimates of the beam-pattern factor as a function of signal-to-noise ratio and angular location of the target. Results of a Monte Carlo simulation of the effect of interference on the various processing techniques are presented. Some of the problems encountered in implementing the various techniques are discussed.     

基于分数阶傅里叶变换的水下目标速度估计

在高斯白噪声背景下,匹配滤波器作为线性调频信号的最优检测器,在水声信号处理中被广泛应用。 当发射信号为线性调频信号时,由水下目标径向速度引起的多普勒频移会造成回波和样本之间失配, 使匹配滤波器的检测性能下降,增加了目标速度估计的难度。 利用分数阶傅里叶变换对于线性调频信号的聚焦特性,提出了应用分数阶傅里叶变换的水下运动目标线性调频回波检测算法,完成对目标速度的估计, 推导目标运动速度与分数阶傅里叶变换阶数之间的关系,并对测量结果进行误差分析。 仿真测试表明,该算法可有效地估计混响背景下的目标径向速度,且具有良好的估计性能。     

A programmable microcomputer-based sonar echo processor for real-time processing

A programmable microcomputer-based sonar echo processor has been developed and field tested to process echo data in real time. The device was designed for use in fisheries acoustics and to analyze echoes from the sea floor. The instrument simultaneously performs the functions "echo integration" and "echo peak detection' on the sonar signal. The "echo integration" circuitry measures the relative acoustic energy of the echo while the "echo peak detection' electronics measure the probability density function (PDF) of the peak of the echo envelope. Each process is gated so the echoes may be processed in many short time intervals. In fisheries applications, estimates can be made of fish density (fish per unit volume), average backscattering cross section, and a combination of fish size and behavior. When using the device to analyze bottom echoes, it is possible to measure both the returned energy from the bottom sediment interfaces and the microrelief characteristics. The durability, flexibility, computer link, and floppy-disk data-storage features of the system are discussed. Data are presented of the processed echoes from biological organisms and the ocean bottom from a recent research cruise on the Atlantic Ocean near Cape Hatteras, NC. The biological results illustrated the organisms to be clearly divided into two separate spatial distributions-an observation not obvious from a standard echogram which was simultaneously used. The results from the bottom showed both 1) the difference in sub-bottom structure between two locations and 2) changes in microrelief of the water-bottom interface between another pair of locations.     

水雷目标识别中的数据融合技术

主动声纳发射声信号“照射”被识别目标,并从目标产生的回波中提取出目标的特征信息,结合可能得到的先验知识,对目标的类别作出判断。论文偿试把现代信号处理技术与信息融合技术相结合,应用到具体的水雷目标识别领域,以提高水雷回波识别系统的准确性和可靠性。     

Minimising errors in estimating fish population and biomass densities using the ‘acoustic volume backscattering strength’ method

The basic acoustical methods for estimating the volume backscattering strength and the absolute biomass density are commonly known. However, the detailed techniques for minimising errors in fitting the calibrated parameters of an echo sounding system in these computations are still not adequately examined and discussed. This paper describes and discusses the following computing techniques involved in the absolute biomass estimation: (i) the fitting of the calibrated time varied gain (TVG) curve, the selection of its operating interval, and the correction of its response; (ii) the compensation for the limitation of the signal bandwidth; (iii) the computation of the equivalent beam width of a transducer using its calibrated beam patterns; and (iv) the accuracy in the conversion from the volume backscattering to the absolute fish density using individual fish target strength measurements.     

MUSIC算法在国产多波束测深仪中的应用研究

针对现有以常规波束形成技术为基础的多波束测深算法中存在空间分辨率不足的问题,将子空间类高分辨算法MUSIC应用到国产多波束测深系统中,探索提高多波束系统空间分辨力的方法。对MUSIC算法原理进行了数学表达式推导和性能分析,并通过计算机仿真、湖上试验数据处理验证了本算法能降低回波到达角度的估计误差,有效地提高了空间方位估计精度,具有实际应用的可行性。     

A Novel Method for Real-Time Monitoring of Channel Siltation Based on Bistatic Scattering Theory

Monitoring the thickness changes of channel siltation is paramount in safeguarding navigation and guiding dredging.This paper presents a novel method for realizing the field monitoring of channel siltation in real time.The method is based on the bistatic scattering theory and concerned more with the receiving and processing of multipath signal at high-frequency and small grazing angle.By use of the multipath propagation structure of underwater acoustic channel,the method obtains the silt thickness by calculating the relative time delay of acoustic signals between the direct and the shortest bottom reflected paths.Bistatic transducer pairs are employed to transmit and receive the acoustic signals,and the GPS time synchronization technology is introduced to synchronize the transmitter and receiver.The WRELAX (Weighted Fourier transform and RELAX) algorithm is used to obtain the high resolution estimation of multipath time delay.To examine the feasibility of the presented method and the accuracy and precision of the developed system,a series of sea trials are conducted in the southwest coast area of Dalian City,north of the Yellow Sea.The experimental results are compared with that using high-resolution dual echo sounder HydroBoxTM,and the uncertainty is smaller than ±0.06 m.Compared with the existing means for measuring the silt thickness,the present method is innovative,and the system is stable,efficient and provides a better real-time performance.It especially suits monitoring the narrow channel with rapid changes of siltation.