卫星导航系统时间测试评估方法研究

发布时间：2018-03-20 04:08

本文选题：系统时间　切入点：广播　出处：《中国科学院研究生院（国家授时中心）》2013年博士论文　论文类型：学位论文

【摘要】：目前的卫星导航系统都是以时间测量为基础的，时间测量的精度直接影响到卫星导航系统的定位、测速功能，精确的时间测量首先需要建立一个统一的时间参考——系统时间，然后通过时间同步技术，将系统内各原子钟的时间同步到系统时间，并最终通过卫星将系统时间广播给用户。此外，授时是卫星导航系统的重要功能，所以需要卫星导航系统的系统时间能够溯源到国际标准时间——协调世界时（UTC）。系统时间是卫星导航系统的核心要素，系统时间及其广播和溯源的性能水平直接影响到卫星导航系统的性能和用户的定位、测速及获得授时服务的精度，因此对系统时间的测试评估具有十分重要的意义。在国外卫星导航系统的研制与建设过程中，对系统时间的监测与评估工作一直受到广泛重视并长期开展，而我国北斗系统的建设起步较晚，还没有系统性的测试评估方法、技术和平台。本论文的研究就是为了填补这方面的空白，研究系统时间测试评估的理论、方法和技术，建立测试评估系统，研制相关软件，为北斗卫星导航系统的研制与建设提供有益帮助。论文的主要研究内容如下： 1、研究了北斗系统时间的测试评估方法，搭建了测试评估系统，分析了在现有条件下，三种时间比对链路的测试精度和不同特点；研究了在不同的性能评估要求下，时间比对链路、采样时间的选择方法，对北斗系统时间的性能进行了测试评估。结果表明，北斗系统时间的频率准确度优于2E-13，7天的频率稳定度略高于1E-14，基本达到了设计的指标要求。 2、针对北斗系统的特点，，提出了采用两套移动校准站对双向时间比对系统设备时延进行校准的方法，并深入研究了卫星双向时间比对设备时延变化的特点和小量级误差的特点及其修正方法。 3、从用户角度出发，提出了系统时间广播性能的测试评估方法，设计了北斗系统时间广播性能的测试评估系统，试验结果表明北斗单星广播系统时间的稳定度优于5ns，准确度还有待提高，可以考虑对系统差做进一步校准。 4、从系统层面出发，对GNSS溯源性能的测试评估方法进行了研究，并以北斗和GPS为例，搭建了测试评估系统进行试验，试验结果表明相比GPST15ns以内的溯源偏差变化，BDT的溯源偏差在30ns以内波动。GPST向UTC的溯源性能高于BDT，其溯源的误差优于1.5ns，而BDT向UTC溯源的误差达到了20ns。
[Abstract]:At present, the satellite navigation system is based on time measurement. The accuracy of time measurement directly affects the positioning of satellite navigation system, the function of velocity measurement, and the accurate time measurement. First of all, a unified time reference-system time is needed. Then through the time synchronization technology, the time of each atomic clock in the system is synchronized to the system time, and finally the system time is broadcast to the user through the satellite. In addition, the timing service is an important function of the satellite navigation system. Therefore, the system time needed for satellite navigation system can be traced to international standard time-UTC. System time is the core element of satellite navigation system. System time and its broadcast and traceability level directly affect the performance of satellite navigation system and the positioning of users, speed measurement and accuracy of time service. Therefore, it is of great significance to test and evaluate the system time. In the process of development and construction of satellite navigation system abroad, the monitoring and evaluation of system time has been widely paid attention to and carried out for a long time. However, the construction of Beidou system in our country started relatively late, and there is no systematic test and evaluation method, technology and platform. The purpose of this paper is to fill in the blank in this respect, to study the theory, method and technology of system time test and evaluation. The establishment of test and evaluation system, the development of related software, for the development and construction of the Beidou satellite navigation system to provide useful help. The main contents of this paper are as follows:. 1. The test and evaluation method of Beidou system time is studied, the test evaluation system is built, the test accuracy and different characteristics of the three time comparison links are analyzed under the existing conditions, and the different performance evaluation requirements are studied. The performance of Beidou system is tested and evaluated by the time comparison link and sampling time selection method. The results show that, The frequency accuracy of Beidou system is better than that of 2E-13 / 7 days. The frequency stability of Beidou system is slightly higher than 1E-14, which basically meets the requirements of the design. 2. According to the characteristics of Beidou system, two sets of mobile calibration stations are proposed to calibrate the time delay of the system equipment. The characteristics of the time-delay variation of the equipment and the characteristics of the small-order error and the correction method are also studied in detail. 3. From the point of view of users, the test and evaluation method of system time broadcast performance is put forward, and the test and evaluation system of Beidou system time broadcast performance is designed. The experimental results show that the time stability of Beidou single satellite broadcasting system is better than that of 5 ns, and the accuracy still needs to be improved. Further calibration of the system difference can be considered. 4. From the system level, the testing and evaluation method of GNSS traceability is studied. Taking Beidou and GPS as examples, the test and evaluation system is built and tested. The experimental results show that the traceability of UTC is better than that of UTC, and the error of tracing to UTC is better than 1.5 ns, while the error of BDT to UTC is 20ns. the results show that the traceability of UTC is higher than that of BDTs in the range of 30ns, and the traceability of BDT to UTC is better than that of BDTs.
【学位授予单位】：中国科学院研究生院（国家授时中心）
【学位级别】：博士
【学位授予年份】：2013
【分类号】：P228.4

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