基于Cesium平台的导航卫星轨道模拟与可视化

发布时间：2019-03-28 12:33

【摘要】：随着计算机和互联网技术的发展,知识与信息的普及和共享逐渐成为这个时代的主题。网络的发达极大减少了信息不对等,专业数据现在也能为普通人获取和使用,而众多"开源"工具的出现也降低了应用开发的成本,促进了网络产品的多样化,其中也包括对GNSS可视化的研究。互联网提供了丰富的研究导航卫星运动的数据、资料、方法和工具,人们可以方便地获取这些内容。但目前关于GNSS轨道模拟与可视化的研究多采用二次开发的方式完成。这种方式不仅需要支付组件购置费,要求研究者具备一定的导航和通信专业知识,以及多种计算机语言编程能力。而且开发成品以需要下载安装的软件为主,网络传播效率不够高。在开发成本、传播成本、传播效率上,这种实现方式并不适应web生态。以Cesium为代表的运行于web端的数字地球产品则可以作为卫星轨道可视化平台,创建以GNSS为研究主体的可视化应用,弥补上述开发现状的不足。本文以全球四大GNSS卫星和太空垃圾为研究对象,提出具有流式数据传输特点的,基于Cesium平台的太空目标物轨道模拟与可视化方法:本研究采用权威发布的目标物轨迹参量和天文模型计算其运动轨迹;使用新型文本语言CZML来记录和描述目标物运动状态;发挥CZML格式的特色传输机制,使用SSE技术(Server-Sent Event)实现CZML轨道数据的流式传输,减轻web端数据通信压力,提高可视化效率与交互体验。论文首先搜集目标物的轨道参数资料——两行根参数(TLE,Two Line Element),与天文学计算脚本——SGP4结合,计算各目标物轨迹数据,将结果存储到CZML文件中;接着将SSE技术与CZML特有的流式传输机制结合,实现轨道数据的流式传输;最后使用Cesium API搭建web端的GNSS轨道模拟与可视化系统。该系统不仅提供基本的导航卫星和太空垃圾的轨迹可视化功能,还可以进行卫星星下点位置、过顶预报等卫星天文属性信息的查询,为用户了解导航卫星和太空提供更加全面、科学的认知途径。本文提出的基于Cesium数字地球平台的全球GNSS卫星轨道模拟与可视化方法,实践门槛低、可视化信息丰富、交互性强、数据传输快,是契合web网络平台与HTML5新规范的数据可视化思路。该方法将有助于以更加生动、有趣又不失科学性的方式表达、展示、交流卫星的轨道、姿态信息,以及包括太空垃圾在内的科学知识,为增进人们对导航卫星的认识乃至提高太空意识都有所裨益。
[Abstract]:With the development of computer and Internet technology, the popularization and sharing of knowledge and information has gradually become the theme of this era. The development of the network has greatly reduced information inequality, professional data can now be accessed and used by ordinary people, and the emergence of many "open source" tools has also reduced the cost of application development and promoted the diversification of network products. It also includes the research of GNSS visualization. The Internet provides a wealth of data, information, methods and tools for studying GNSS movements that people can easily access. But at present, the research on GNSS orbit simulation and visualization is done by the way of secondary development. This approach not only needs to pay for the purchase of components, but also requires the researcher to have a certain degree of navigation and communication expertise, as well as a variety of computer language programming capabilities. And the development of finished products to need to download and install the software-based, network communication efficiency is not high enough. In terms of development cost and communication efficiency, this implementation is not suitable for web ecology. The digital earth products, such as Cesium, which run on the web, can be used as the visualization platform of satellite orbit, and the visualization application based on GNSS can be created, which can make up for the deficiency of the above-mentioned development situation. In this paper, four major GNSS satellites and space garbage in the world are studied, and the features of streaming data transmission are proposed. The orbit simulation and visualization method of space object based on Cesium platform: in this study, the trajectory parameters and astronomical model are used to calculate the trajectory of the object. A new text language, CZML, is used to record and describe the moving state of the object. This paper gives full play to the characteristic transmission mechanism of CZML format, uses SSE technology (Server-Sent Event) to realize the streaming transmission of CZML track data, lightens the pressure of data communication on the web end, and improves the visualization efficiency and interactive experience. Firstly, the orbital parameters of the target-two-line root parameters (TLE,Two Line Element),) combined with the astronomical script-SGP4 are collected to calculate the trajectory data of each target, and the results are stored in the CZML file. Then the SSE technology and the special streaming transmission mechanism of CZML are combined to realize the streaming transmission of track data. Finally the GNSS orbit simulation and visualization system on the web end is built by using Cesium API. The system not only provides basic navigation satellite and space garbage trajectory visualization function, but also can query satellite astronomical attribute information such as satellite subsatellite point position, over-top prediction and so on, so as to provide users with a more comprehensive understanding of navigation satellite and space. The cognitive pathway of science. The method of global GNSS satellite orbit simulation and visualization based on Cesium digital earth platform is presented in this paper, which has the advantages of low threshold of practice, rich visualization information, strong interaction and fast data transmission. Is in line with web network platform and HTML5 new specification of data visualization ideas. This approach will help to express, demonstrate and exchange satellite orbit, attitude information, and scientific knowledge, including space debris, in a more vivid, interesting and scientific way. It is helpful to improve people's understanding of navigation satellites and even to raise awareness of space.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.4

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