伪码测距技术研究及fpga仿真设计

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1、4.1.2循环相关搜索捕获········································································35 4.1.3双门限的恒虚警率捕获·································································37 4.2伪码跟踪·······························································································38 4.3本章小结·········

2、······················································································41 第5章基于FPGA的伪码测距设计·····························································42 5.1FPGA·····································································································42 5.2VHDL语言···

3、·························································································43 5.3测距系统设计·······················································································46 5.4本章小结······························································································

4、·48 结论··················································································································49 参考文献··········································································································51 攻读硕士学位期间承担的科研任务与主要成果····································

5、········56 致谢··················································································································57 作者简介··········································································································58V万方数据第1章绪论1.1课题的意义及背景小卫星编队飞行是空间技术发展的一个新的领域。所谓小卫星编队

6、飞行是指由若干个小卫星组成一定的阵列，实现特定功能的一种编队飞行方式。卫星编队实际上是由物理上分离且联合实现同一空间使命的一系列卫星组成的空间系统，亦称分布式卫星或分布式空间系统[1-3]。与单个卫星相比，多颗小卫星组成的分布式系统与传统单颗卫星或普通星座相比除低廉的发射和制作成本外，更具灵活性和冗余度，更能容忍单点故障，降低任务失败风险。编队飞行的另一特点是具有很高的自主性，对地面站依赖性不大[4]。卫星自主导航是编队小卫星实现其空间使命的基本要求之一。卫星自主导航是指卫星在不依赖地面站的条件下，仅仅依靠卫星上的测量设备实时地确定编队中各个卫星的相对位置、速度以及加速度，在轨

7、完成飞行任务所要求的功能或操作[5]。实现自主导航可以减轻地面站的操作负担，降低航天计划的成本，提高卫星的生存能力，以及扩展卫星的应用潜力。卫星自主导航的全面应用为星间相对状态测量提出更高的要求。星间相对状态测量包括相对位置、相对速度和相对姿态测量。星间测距与通信是其中重要一环。伪码测距技术是将伪码加载到无线电中，通过测量伪距实现星间距离测量的一种测量手段。无线电由于波束宽、作用距离远、测量精度较高，实时性强、可全天候工作，且在测量的同时具有信息通信功能，满足小型化、低功耗、多航天器相对测量