海底光缆检测技术综述     

汤钟  邵浩  张斌 《数字海洋与水下攻防》2020,3(6):499-503

据统计，我国近岸70%以上海底光缆失效是遭受了渔船拖网作业或抛锚等活动的破坏。维护损坏的海底光缆，首先需要快速准确地定位光缆损坏段，同时获取光缆在海床上的布设状态以及布设区域的海床地形特征、地貌与底质特征等信息。在实际工作中，复杂的海床环境为海底光缆的检修及维护带来巨大的技术困难。围绕海底光缆巡检的技术需求，系统分析了常规海底光缆检测技术的特点，基于国内外水下无人机器人的发展现状，为提高海底光缆的检测效率、识别准确率和智能化水平提供了技术支撑。  相似文献   

Instantaneous Shorelines as an Intermediate for Island Shoreline Mapping based on Aerial/Satellite Stereo Images     

Yamin Dang  Xinghua Zhou  Jun Xu  Shuqiang Xue 《Marine Geodesy》2018,41(3):219-229

Island shoreline mapping based on field measurements by collecting visually discernible features is costly and even unrealistic to be implemented in practice because of the nonuniqueness, fuzziness, and ambiguity of shoreline features. The MHHW (the mean higher high water) shoreline, i.e., the intersection of the coastal profile with the MHHW, is recommended to be chosen as a significant shoreline indicator of an island. An approach for mapping the MHHW shoreline using the aerial/satellite stereo images is proposed. In the proposed procedure, first, the height difference between the instantaneous shoreline and the MHHW shoreline is calculated by the ocean tide model; then the orthometric/normal height of the instantaneous shoreline is determined from the stereo images; last, the instantaneous shoreline is used as an intermediate for determination of the height of the MHHW shoreline. The proposed procedure is applied to the MiaoZiHu Island located in the East China Sea. Preliminary experimental result shows that in ideal cases, the horizontal positional accuracy of the extracted shoreline can reach 0.2 m from aerial images of 0.1 m resolution.  相似文献   

磁梯度张量系统的非线性集成矢量校正          下载免费PDF全文

李青竹  李志宁  张英堂  范红波  尹刚 《武汉大学学报(信息科学版)》2019,44(5):714

磁梯度张量系统测量精度受到单磁传感器系统误差与传感器阵列间非对准误差的严重影响。为了获得精确的张量测量输出，建立了单磁传感器零漂、标度因子与非正交角等系统误差和多传感器轴系间非对准误差的集成数学模型，提出了基于十字磁梯度张量系统最小二乘非线性集成校正方法。相比两步标量校正，利用建立的集成数学模型能够一次性估计出十字形张量系统的48个误差参数，以"人造"平台输出为参考实现低成本矢量校正，极大提高了校正效率和参数估计准确率。仿真和实测表明，张量系统误差参数仿真估计准确率高于99.75%，实验校正后总场输出均方根误差（root mean square error，RMSE）小于2 nT，张量分量RMSE小于50 nT/m，参数估计具有较高的鲁棒性。  相似文献   

Erratum to: Relationships between intensity of the Kuroshio current in the East China Sea and the East Asian winter monsoon     

Ming Yin  Xin Li  Ziniu Xiao  Chongyin Li 《海洋学报(英文版)》2018,37(9):119-119

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对抗航空磁探的磁诱饵模拟指标分析及度量方法          下载免费PDF全文

石剑  刘忠乐  孙强  王亮 《数字海洋与水下攻防》2018,1(2):36-41

针对航空磁探的威胁,潜艇可通过施放能够模拟其空中磁场特性的装置(磁诱饵)进行对抗，在对磁诱饵进行研究时,需要对其模拟需求进行分析。针对此问题,在对目前常用磁探仪工作原理及优缺点进行分析的基础上建立了基于标量磁探仪的航空磁探潜模型,以所建立的航空磁探潜模型为基础,分析了对抗航空磁探时磁源所需满足的模拟需求,并给出对抗效能评估度量方法及指标:磁场功率比、磁场方向可调性指标及有效面积指标,为潜艇空中磁场模拟方法研究的开展提供了基础。  相似文献   

FY-4A卫星海域云图图像增强融合方法研究          下载免费PDF全文

尹锡帆  赵辉  孙文舟  郭晓明  蒋善伟  刘言志 《海洋测绘》2020,40(5):30-34

FY-4A卫星是我国目前最先进的气象卫星,为缓解光照对其可见光和红外云图影响,增强图像质量和显示细节,通过分析中央气象台发布的FY-4A卫星云图中可见光和红外云图资料,指出云图可见光和红外云图存在极强互补性的特征,提出一种基于灰度均值的自适应非线性Gamma图像增强融合方法。仿真实验结果指出利用本文方法得到的融合云图拥有显示云的更多细节和识别云层云类的特点。该方法有效性的验证,为21世纪海上丝绸之路气象预报保障提供了新的云图识别处理技术。  相似文献   

不规则三角网数字水深模型缓冲面快速构建的滚动球加速优化算法     

董箭  张志衡  彭认灿  李改肖  王沫 《测绘学报》2019,48(5):654-667

针对TIN_DDM缓冲面构建与应用中存在的数据类型特殊、算法效率与模型精度不匹配的问题,本文将滚动球模型应用扩展至TIN_DDM缓冲面的构建过程。在分析滚动球模型构建精度局限的基础上,建立了滚动球半径关联的滚动球模型整体精度控制方法;结合大数据量TIN_DDM缓冲面多次构建的应用效率需求,阐明了关键采样点与滚动球半径对TIN_DDM缓冲面构建效率的影响规律;设计了TIN_DDM缓冲面构建关键采样点的判定准则,建立了关键采样点与滚动球半径的数值关联关系;提出了一种基于滚动球加速优化模型的TIN_DDM缓冲面快速构建算法,算法时间复杂度为O(n)。试验结果表明:本文算法可实现任意缓冲半径条件下TIN_DDM缓冲面的多次快速构建,且算法精度控制在2σ内。  相似文献   

基于一维综合孔径微波辐射计的海面温度反演研究   总被引：1，自引：0，他引：1  

艾未华  冯梦延  陈冠宇  陆文 《海洋学报(英文版)》2020,42(5):115-122

Due to the low spatial resolution of sea surface temperature(T_S) retrieval by real aperture microwave radiometers,in this study, an iterative retrieval method that minimizes the differences between brightness temperature(T_B)measured and modeled was used to retrieve sea surface temperature with a one-dimensional synthetic aperture microwave radiometer, temporarily named 1 D-SAMR. Regarding the configuration of the radiometer, an angular resolution of 0.43° was reached by theoretical calculation. Experiments on sea surface temperature retrieval were carried out with ideal parameters; the results show that the main factors affecting the retrieval accuracy of sea surface temperature are the accuracy of radiometer calibration and the precision of auxiliary geophysical parameters. In the case of no auxiliary parameter errors, the greatest error in retrieved sea surface temperature is obtained at low T_S scene(i.e., 0.710 6 K for the incidence angle of 35° under the radiometer calibration accuracy of0.5 K). While errors on auxiliary parameters are assumed to follow a Gaussian distribution, the greatest error on retrieved sea surface temperature was 1.330 5 K at an incidence angle of 65° in poorly known sea surface wind speed(W)(the error on W of 1.0 m/s) over high W scene, for the radiometer calibration accuracy of 0.5 K.  相似文献   

可视化水下航行体控制系统数学仿真软件设计     

黄凡 《数字海洋与水下攻防》2020,3(4):355-362

提供一种水下航行体控制系统数学仿真软件的设计方案，在该仿真软件平台上可以完成水下航行体控制系统数学仿真研究、水下航行体水动力参数辨识实验和实航内测数据及仿真实验结果三维可视化显示。详细设计了该软件包含的 4 大模块：水下航行体数学模型及仿真模型模块、控制算法模块、流体动力参数辨识模块和图形界面人机交互模块，并对仿真模型的配置做了简单介绍。  相似文献   

Characteristics of the Asian–Pacific Oscillation in Boreal Summer Simulated by BCC_CSM with Different Horizontal Resolutions     

Yazhou Zhang  Zhijie Liao  Yaocun Zhang  Feng Nie 《大气科学进展》2016,33(12):1401-1412

The summer Asian–Pacific Oscillation(APO) is a major teleconnection pattern that reflects the zonal thermal contrast between East Asia and the North Pacific in the upper troposphere. The performance of Beijing Climate Center Climate System Models(BCC CSMs) with different horizontal resolutions, i.e., BCC CSM1.1 and BCC CSM1.1(m), in reproducing APO interannual variability, APO-related precipitation anomalies, and associated atmospheric circulation anomalies, is evaluated.The results show that BCC CSM1.1(m) can successfully capture the interannual variability of the summer APO index. It is also more capable in reproducing the APO's spatial pattern, compared to BCC CSM1.1, due to its higher horizontal resolution. Associated with a positive APO index, the northward-shifted and intensified South Asian high, strengthened extratropical westerly jet, and tropical easterly jet in the upper troposphere, as well as the southwesterly monsoonal flow over North Africa and the Indian Ocean in the lower troposphere, are realistically represented by BCC CSM1.1(m), leading to an improvement in reproducing the increased precipitation over tropical North Africa, South Asia, and East Asia, as well as the decreased precipitation over subtropical North Africa, Japan, and North America. In contrast, these features are less consistent with observations when simulated by BCC CSM1.1. Regression analysis further indicates that surface temperature anomalies over the North Pacific and the southern and western flanks of the Tibetan Plateau are reasonably reproduced by BCC CSM1.1(m), which contributes to the substantial improvement in the simulation of the characteristics of summer APO compared to that of BCC CSM1.1.  相似文献