共查询到20条相似文献，搜索用时 250 毫秒
1.
横向分辨率是多波束系统探测分辨率的主要决定因素,当进行水下目标探测时,其直接影响着探测极限深度的选择。探讨了顾及横向分辨率的水下目标探测极限深度的计算,并以SeaBeam3030型多波束系统为例,给出了等角和等距两种模式的极限深度计算方法,通过仿真计算与分析,验证了计算方法的有效性。结论表明:无论是等角还是等距模式,横向分辨率由中央向外分辨率逐渐增大,并且在等距模式下,探测目标在横向上边缘失真明显,数据不能用于成图。给出的顾及横向分辨率的极限深度计算方法,可为不同类型的多波束测深系统进行水下目标探测提供依据参考。 相似文献
2.
3.
探测水下450m深处的小目标(大概5m高)可应用Simmd EM300多波束声纳，而之前通常是用59kHz的深水拖曳旁扫声纳来探测的。EM300多波束声纳系统采用多扇区扫描技术，可进行实时偏航、横摇和纵摇校验，动态地改变扇面角度，在450m深度能够保持每隔10m一次的水深测量密度，这比最宽的波束“脚印”(16-64m)小了很多。目标在观测数据中若隐若现，这比数字模型再现的几何成像结果好。在数字模型中，尝试了各种不同而EM300也能实现的几何成像，包括对比等角和等距的波束间隔，不同条幅开角以及所有不同的发射和接收波束宽度的组合。当振幅检波被那些小于横向波束脚印宽度的目标所混淆时，在信噪比有利的条件下。相位检波检测目标的最小尺寸能达到横向波束宽度的等级。这样，波束间隔控制在这个范围是比较恰当的，小目标造成的相位失真现象最终影响不大。 相似文献
4.
5.
6.
7.
8.
9.
推导了海洋条件下目标-背景对比度的计算公式,根据辐射传输方程,采用Eddington近似方法求解,建立了海洋条件下目标-背景对比度的表达公式。计算并分析了太阳高度、观测者角度、海水体衰减系数及目标所处深度对目标-背景对比度的影响。文中得出如下结论:垂直方向侦查时,太阳高度角在40°左右条件下的目标-背景对比度最大,最容易侦查到水下目标;目标-背景对比度随目标所在深度增大而减小,随海洋体衰减系数的增加而降低;太阳高度角为90°、观测者天顶角余弦在0.8~0.9范围时的目标-背景对比度存在较大尖峰值。研究结果为光学探测水下目标及水下航行器反光学探测提供理论支撑。 相似文献
10.
11.
《Oceanic Engineering, IEEE Journal of》2009,34(4):539-547
12.
13.
14.
Underwater acoustic networks 总被引：8，自引：0，他引：8
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 相似文献
15.
姚芳华 《数字海洋与水下攻防》2020,3(1):82-86
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。 相似文献
16.
17.
18.
19.
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 相似文献