【作者】 李俊生；

【导师】 郑林华；

【作者基本信息】 国防科学技术大学 ， 信息与通信工程， 2006， 硕士

【摘要】 航天测控技术是航天技术的重要组成部分,测控系统为航天飞行器正常飞行提供必不可少的技术保障。随着航天技术的发展,航天测控技术也在不断向前推进,各种新的测控技术和测控系统不断涌现,旧的测控系统逐渐被淘汰。随着扩频通信技术的成熟,其应用也越来越广泛,凭借扩频本身所具有的优点,如信号功率谱密度低、对邻近信道干扰小、保密性强难以被截获、可以实现码分多址等,扩频通信在卫星测控领域扮演愈来愈重要的角色。扩频测控通信系统是未来航天测控通信系统的发展方向。在卫星测距定位方面,扩频伪码测距的优势也很突出,可以弥补传统侧音测距的不足。由于伪随机码固有的测距能力——其长周期和互相关特性,使得在测距距离和精度方面可以同时提高,采用码分多址技术可以实现对多个目标同时进行测控。基于伪随机码存测距方面的这些优点,本文研究了伪随机码测距在卫星测控系统中的理论基础和具体应用。本文讨论了四种测距方法,包括侧音测距、伪码测距、载波相位测距和混合测距法,讨论了其测距原理,分析其误差来源,以及各种测距方法的性能优劣。重点研究了伪码测距的距离模糊问题和测距精度的提高。给出了一种混合测距方案,分析了其测距所能达到的长度和精度。分析了伪码测距不同方案间的性能差异和实现难度。研究了伪码测距的关键技术:长周期码的设计,伪码快速捕获及其实现结构。针对伪码精确跟踪的数字延迟锁定环,进行了仿真,结果表明环路滤波器的设计对伪码跟踪精度有重要影响。最后介绍了伪随机码测距在时间统一系统中的应用。更多还原

【Abstract】 TT&C (telemetry telecontrol & communication) used in spacecraft is the most important part of the spacecraft technology. Normal space navigation relies on the TT&C system. With the development of spacecraft technology, the technology of telemetry and telecontrol has being promoted. The new and advanced technology comes forth and the old telemetry and telecontrol system is replaced or eliminated.With the spread—spectrum technology development, spread—spectrum technology is broadly used. On account of its advantage, such as low interrupt on the other channel, its hard captured for the enemy and its CDMA, and so on , it is becoming more and more important in the telemetry and telecontrol system. The spread—spectrum TT&C (telemetry telecontrol & communication) is the future spacecraft TT&C’s orientation. Compared with the deficiency of tone-ranging,the spread-spectrum PN is good at space ranging. As the PN-code high performance of long period and the coherence, the very long distance and high precision ranging can be reached at the same time. Multi-target TT&C can be reached by CDMA of PN. As the advanced of PN ranging, this paper presents the PN-code’s application in space TT&C.This paper presents four kinds of ranging method, including tone-ranging, PN-code ranging, carrier phase ranging and mixed ranging. The principle of ranging, source of ranging error and the comparison between them are discussed. The ranging ambiguity and the precision are studied as key points. A mixed ranging scheme is put forward, the distance and precision it can be reached are analyzed. The different performance and difficulty among these methods are analyzed. The key technology of PN-code ranging is studied, such as long periodic PN-code’s design, PN-code rapid acquisition and its implement. The DLL used for the PN-code precision is simulated. The result shows that the loop filter has important influence on the tracking precision. Finally, we introduce the PN-code ranging applications in time unified system.更多还原