复杂地形环境下可见星仿真分析

发布时间：2018-03-23 12:19

本文选题：可见星　切入点：GPS　出处：《燕山大学》2013年硕士论文

【摘要】：以GPS为基础的卫星导航应用技术已经十分成熟，由于用户在地面接收GPS卫星信号，不可避免的会受到人工或自然物的遮挡，因此在某些方面以及某些地区，卫星定位导航技术仍然受到一定程度的限制，以至导航精度得不到保证，甚至不能够确定接收机所在的位置。伪卫星定位技术能够显著增强区域定位精度，然而伪卫星布设必须以该地区卫星的可见情况为前提。首先，本文介绍了免费获取数字高程模型（DEM）的方法，以及Global Mapper的使用。其次，介绍了GPS系统中一些常用的时间空间坐标系及其转换方法，正确理解空间坐标以及时间坐标对于卫星位置判断等有重要影响；对星历文件及星历数据的外推进行了探讨；针对给定时间，给定区域，计算卫星相对于接收机的仰角以及方位角，在分析了地形因素的情况下，，给出了障碍物仰角及可见星的计算方法；仿真生成载体运动轨迹，实时判断可见星的变化。最后，以九寨沟地区的GPS卫星可见情况为基础，讨论了首要考虑伪卫星“有效性”次要考虑GDOP值的伪卫星布设方法的可行性，仿真分析了伪卫星在复杂地形环境下的可视域范围。根据本文给出的伪卫星布设准则，给出了九寨沟景区伪卫星布设方案。对比伪卫星布设前后GDOP（几何精度因子）值以及“可见星”数量的变化，表明本文伪卫星布设方法有效，可以提高整个导航系统的可用性、可靠性、稳定性以及测量精度。
[Abstract]:The satellite navigation application technology based on GPS is very mature. Because users receive GPS satellite signals on the ground, it is inevitable that they will be shielded by artificial or natural objects, so in some aspects and in some areas, Satellite positioning and navigation technology is still limited to a certain extent, so that navigation accuracy can not be guaranteed, or even the location of the receiver can not be determined. Pseudosatellite positioning technology can significantly enhance the regional positioning accuracy. However, pseudosatellite placement must be based on the visibility of satellites in the region. Firstly, this paper introduces the method of obtaining free digital elevation model (DEM) and the use of Global Mapper. Secondly, some commonly used time and space coordinate systems and their conversion methods in GPS system are introduced. The correct understanding of space coordinates and time coordinates have important influence on satellite position judgment. The external propulsion of ephemeris and ephemeris data is discussed, and the elevation and azimuth of the satellite relative to the receiver are calculated for a given time and region, and the terrain factors are analyzed. The calculation method of obstacle elevation angle and visible star is given, and the moving track of carrier is generated by simulation to judge the change of visible star in real time. Finally, on the basis of the visible situation of GPS satellites in Jiuzhaigou area, the feasibility of pseudosatellite placement method with the first consideration of pseudosatellite "validity" and the consideration of GDOP value is discussed. The visual range of pseudosatellites in complex terrain environment is simulated and analyzed. A pseudosatellite layout scheme of Jiuzhaigou scenic area is given. By comparing the changes of GDOP (geometric Precision Factor) and the number of visible satellites before and after the pseudosatellite placement, it is shown that the pseudo-satellite placement method in this paper is effective and can improve the usability of the whole navigation system. Reliability, stability and measurement accuracy.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P228.4

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