全球卫星导航系统星间链路层协议设计

分析了全球卫星导航系统（GNSS）发展的现状，指出建立GNSS星间链路（ISL）的需 求。针对这样的需求，提出以高级在轨系统（AOS）空间数据链路层协议建议书为参考来设 计适用于GNSS的星间链路层协议。对GNSS星间可能传输的业务信息基于AOS的建议进行了归 类，认为GNSS星间链路层协议可以使用AOS，具体给出了AOS建议下星间链路层协议的设计。 为使协议更适合GNSS ISL链路层，主要从3个方面对AOS进行改进，即：优化了虚拟信道数 据单元的结构，削减了3种服务，改进了虚拟信道调度与复用方法。对协议的性能进行了分 析仿真，得出了信道误码率、帧长、包长和吞吐量的关系，仿真结果表明所设计的协议可 作为GNSS星间链路协议设计的参考。

Link Layer Protocol Design of Global Navigation Satellite System

This paper analyses the actual state development of Global Navigation S atellite System(GNSS), points out the need of the Inter-satellite Link(ISL) fo r GNSS. To achieve this requirement, it advises the Advance Orbit System(AOS ) Space Data Link Protocol Recommendation can be used as a reference. The possib le traffic which may be sent on ISL is classified based on AOS recommendation. It indicates the AOS can be appropriate. To let the protocol appropriate f or GNSS ISL,three main improvements are made,including optimizing virtual channe l data un it frame structural components, reducing three services and improving on schedul ing and multiplexing scheme. A link layer protocol is designed and its performan ce is simulated. The relationship among Bit Error Rate(BER), frame length, packe t length and throughput is analysed. The simulation results show that the proto col designed can be a reference for GNSS.