【作者】 张大勇；

【导师】 金一丞；

【作者基本信息】 大连海事大学 ， 交通信息工程及控制， 2003， 硕士

【摘要】 雷达模拟器在海员培训和适任评估中起着重要的作用。随着航海事业的发展，用户对雷达模拟器的要求越来越高，《STCW 78/95公约》也对雷达/ARPA模拟器提出了明确的要求。 在全计算机化的雷达/ARPA模拟器中，仿真图像生成及显示是其核心部分，同时要对雷达/ARPA的各种功能进行模拟。仿真图像包括雷达回波和ARPA符号。雷达回波包括陆地、岛屿回波，各种活动目标的回波，雷康、SART回波，海杂波等。ARPA符号包括包括固定距标圈、活动距标圈、电子方位线、警戒圈、船首线、PI线、已录取目标的矢量线以及历史航迹(或PAD)、试操船符号等。 雷达回波中的海岸线、雷康和SART的原始数据是通过数字化仪从海图中采样获取的，获取后的数据按照预先设计好的数据结构保存在了特定类型的文档中。要使从海图录入的原始数据能够在3种不同的显示方式(船首向上的相对运动显示方式、北向上的相对运动显示方式和北向上真运动显示方式)下正确的显示出来，必然要在几个坐标系(图板坐标系、屏幕坐标系、平面直角坐标系和地理坐标系)中进行一系列的坐标变换。本文第二章详细说明了原始数据的数据结构和各种坐标变换。 在以前的雷达/ARPA模拟器中，雷达回波和ARPA符号都采用扫描线求交算法生成，这不符合真实雷达的工作机制。采用扫描线求交算法生成雷达回波，是一种非常好的选择，但是对于ARPA符号来说，扫描线求交算法则存在明显的不足。比较好的方案应该是采用不同的算法生成雷达回波和ARPA符号，并将其绘制在不同的层面上。 本文第三章详细说明了基于DirectX技术的分层显示方案的实现。采用基于DirectX技术的DirectDraw组件，共生成了12个表面：FrontSurface、BackSuface、BaseSurface、MenuSurface、EchoSurface、Echo BackSurface，MarkSurface、OverlaySurface、CorrSurface、CursorSurface、UnderCursorSurface和UnionCursorSurface。首先把当前雷达图像的各个组成部分分别绘制在不同的表面上，然后把每个表面上的图像逐层地显示到后台表面上，最后通过前后台表面翻转完成雷达图像的交替显示。这种分层显示机制很好的实现了雷达回波和Arpa符号的分层显示。采用该方案还司以很容易地增加一些采用以前的方法不容易生成的图像，为进一步完善雷达／ARPA的功能模拟提供了空间。 本文的第四章阐述了模拟雷达图像的改进算法。 1） 采用扫描线求交回波生成算法和单后备缓存显示相结合的方法比较好地实现了雷达回波旋转扫描显示的高质量仿真，这将在第四章第一节中详细阐述。 2） 雷达回波中海杂波生成模拟的仿真程度，在很大程度上也决定了雷达回波图橡的质量。以前的随机生成算法，不符合海杂波的生成机制。研究发现，海杂波的强度在统计上符合韦布尔分布。如何生成符合韦布尔分布的海杂波将在第四章第二节中论述。 3） 雷达回波中海岸线的原始数据都是通过数字化仪从海图上获取的。获取的数据为一些离散的采样点，通过连接前后两相邻采样点构成折线图形来模拟海岸线。在小量程时（如0．25海里），自然海岸线回波图像的折线化比较明显。采用基于分形思想的岸线口波细化算法，在不用增加采样点的情况下，能够生成具有任意层次精细结构的雷达岸线回波，解决了小量程时的折线化现象。在第四章的第三节，将有对此的详细说明。 4）同频干扰图像的生成和目标误跟踪的模拟使得雷达／ARPA模拟器的功能得到了进一步完善。更多还原

【Abstract】 Radar/ARPA simulator takes the important role in seafarer training, assessment of competence, etc. Radar simulator has been demanded higher performances along with rapid development of marine industry. And the explicit standards are clearly defined by STCW 78/95 Convention.Mimic image generation and display is the kernel part in the full computerized radar/ARPA simulator. At the same time all kinds of rada/ARPA functions must be simulated. Mimic image comprises of radar echoes and ARPA marks. Radar echoes include echoes of lands, islands, all kinds of moving targets, racon, SART and sea, etc. ARPA marks consist of fixed range marker, variable range marker, electronic bearing line, guard zone, heading-line, parallel index(4 navigation lines), vector lines(or PAD) and past track information of tracked target ships, marks of trial manoeuvres, ect.Initial coastline sampling data, racon position data and SART position data are acquired from sea chart by digitizer. All of the initial data are saved with predefined data structure in data files. For displaying the initial date aquired from sea chart correctly in three different display modes(relative head up motion,relative north up motion, true north up motion), a series of coordinate conversion are necessary .In the second chapter, data structure and various coordinates conversion are discussed in details .In the previous radar/ARPA simulator, both radar echoes and ARPA marks are generated with the algorithm of computing intersection point with scanline sweeping (abbreviated to ACIPSS), this does’t accord with the mechanism of radar working. ACIPSS is fit for radar echoes generation. To generate ARPA marks, ACIPSS has its obvious fault. A better way is adoptingdifferent algorithm to generate radar echoes and ARPA marks, then drawing them on different surface.In the third chapter, it is illustrated that how to draw different contents on different surface based on the DirectX technique. In the radar/ARPA simulator, there are 12 surfaces generated for radar image display: FrontSurface# BackSuface# BaseSurface# MenuSurface# EchoSurface# Echo_BackSurface# MarkSurface# OverlaySurface# CorrSurface# CursorSurface# UnderCursorSurface and UnionCursorSurface. First, every part of current radar image is respectively drawed on different surfaces. Second, image on different surfaces are drawed on BackSurface in order. Last, display image through flipping between FrontSurfacd and BackSurface. It will be easy to add new image which is difficult to be generated before by adopting this method. It also provides a great future for the improvement of radar/ARPA function simulation.Improved algorithm for generated radar image are presented in chaper 4:1) ACIPSS is improved in radar echo generation. New method is to combine ACIPSS with single back buffer display. The combination realize high level simulation of true antenna sweep effect. All of the above will be explained in details in chapter 4 section 1.2) Simulation of sea echo determines the quality of radar echo image to a great extent. The random sea echo generation does’t accord with the mechanism of sea echo generation. Research reveals that the intensity of sea echo accords with the Weibull distribution. It will be discussed in chapter 4 section 2 that how to generate sea echo accord with Weibull distribution.3) The initial coastline data which are acquired from chart by digitizer is a series of sampling point. Coastlines are simulated with polylinesbyconnecting two neibour sampling points. Nature coastline looks more like to be a polyline in a small range scale(such as 0.25) on the radar/ARPA screen. The coastline subdivision algorithm based on fractal algorithm could produce coastline with any level details without adding more sampling points. The subdivision algorithm will be listed in chapter 4 section 3. 4} Generation of radar interfrence image and target swap simulation improve the simulation of radar/ARPA simulator.更多还原