【作者】 杨宇；

【导师】 余小游；

【作者基本信息】 湖南大学 ， 信息与通信工程， 2013， 硕士

【摘要】 星座自主导航是全球导航卫星系统（GNSS）未来的重要发展方向，星间测距与通信链路的建立和维持是星座自主导航的基础，而星间链路组网设计又是实现星间链路的重要环节。本文以此为背景，从星间测距与通信的实际需求出发，对导航星座星间链路组网策略相关问题进行了初步研究。具体研究内容包括四部分：（1）针对当前GPS的星间链路体制不再适应未来导航系统的问题，在新的导航系统背景下，根据卫星星座的周期性和有限状态的思想，提出一种适合星间测距及星间通信的工作体制。（2）通过STK、MATLAB仿真，详细分析24MEO+3GEO+3IGSO混合星座星间拓扑结构，包括MEO-MEO链路、GEO/IGSO-MEO链路星间观测的仰角、方位角、距离和星间可视性等。（3）由于卫星上天线数量的限制，如何有效分配天线资源来建立星间链路，以实现星间测距与星间通信功能，是GNSS卫星网络设计的关键问题之一。本文提出一种以卫星位置精度因子最小、同时通信链路代价最小为目标的星间链路设计方法。根据该方法设计的星间链路网络，既能满足卫星的自主定轨要求，也能同时保证网络的连通性和网络的最优通信代价。（4）在MEO固定前后两条同轨、左右两条异轨链路的前提下，计算卫星的位置精度因子值（PDOP），然后从中筛选具有最小PDOP值的链路，减小链路资源分配的复杂程度。在PDOP值小于3的约束下，优先选择具有最小通信代价的链路建立链接，最终达到在同一个网络拓扑中卫星具有最小的PDOP值，且卫星网络的通信代价最小的目标。仿真结果表明，天线仰角主要范围应该在-65°~-35°之间，最佳范围为-70°~-20°，方位角应尽量覆盖0°~360°，对卫星天线方位角、仰角的设计有一定借鉴意义；本文给出的GNSS卫星网络设计方法，使单一卫星的PDOP值最大不超过3，星座整网通信时延约为9秒，同时减少星间链路的切换次数，方法切实可行，并具有一定的实用价值和应用前景。更多还原

【Abstract】 Constellation autonomous navigation is an important future developmentdirection in the global navigation satellite system, the establishment and maintenanceof ranging and communication link is the basis of constellation autonomousnavigation, and inter-satellite link network design is an important part to realize theinter-satellite links. This background, from the actual demand of the inter-satelliteranging and communication, the navigation constellationsn link networking strategyhas made a primary study.The main research contents are including four parts:(1) In view of the current GPS ISL system no longer meet the future navigationsystem, in the background of the new navigation system, according to the periodicityand finite state of satellite constellation, this study proposed a system of ranging andcommunication between satellites.(2) The topology of24MEO+3GEO+3IGSO hybrid constellation was analyzedthrough the Satellite Tool Kit (STK) and MATLAB, including the elevation, azimuth,distance and visibility of MEO-MEO links and GEO/IGSO-MEO links.(3)Due to the limit of the number of satellite antenna, in order to realize theinter-satellite ranging and inter-satellite communication, how to effectively allocateantenna resources to build inter-satellite link is one of the key problem of GNSSsatellite network design. This paper presents a satellite link design method, which isaming at minimizing position dilution of precision and communication link cost. Thenetwork based on design method not only can meet the requirements of the satelliteautonomous orbit determination, but also ensure optimal communication cost andnetwork connectivity.(4) On the premise of MEO built chain with adjacent satellites on the sameorbital plane and satellites on other orbital planes at the same time, calculating PDOP,selecting the link with the minimum PDOP value, it decreases complexity of linkallocation. When PDOP value is less than3, firstly selecting the minimumcommunication cost links to connect, finally satellites achieved minimum value of thePDOP and the satellite network communication cost minimization in the samenetwork topology.The simulation results show that the elevation range should be between -65°~-35°, the optimum range should cover-70°~-20°and azimuth should cover0°~360°, and the information of link elevation, azimuth and distance has certainreference meaning for antenna design，and when the PDOP value of single satellite isless than3and the entire constellation communication delay is about9seconds, at thesame time, it reduces the number of ISL switching. GNSS satellite network designmethod in this paper is feasible, it has certain practical value and applicationprospect.更多还原