双向测距与时间同步系统提高测量精度的方法研究

发布时间：2018-04-28 02:59

本文选题：双向单程伪距测量 + DRTS　；参考：《中国科学院研究生院（国家授时中心）》2014年硕士论文

【摘要】：随着移动通信、全球卫星导航系统等科学领域的不断发展，精密测距与时间同步的重要性越来越凸现出来。很多工程和科学领域都需要精密的时间同步，例如，世界各时间实验室都需要纳秒或者亚纳秒量级的高精度时间同步；卫星的发射和测控，以及试验靶场的原子钟都需要进行标校；导航卫星之间、卫星与地面站、地面站与地面站之间需要高精度的时间同步；另外，自主编队航天器（AFF）、组网飞行器等，也需要进行精密的基线测量和时间同步。因此，研究双向测距与时间同步技术对上述领域的发展具有重要意义。本文通过对双向测距与时间同步系统精度提高方法的研究，重点阐述了提高系统测量精度的两种技术，即载波相位平滑伪距技术和设备时延标定技术。本文的主要研究内容和研究成果如下：（1）本文从双向测距与时间同步系统（DRTS）信号处理算法的角度出发，讨论通过改进原始观测数据预处理算法来提高系统的测距精度。根据载波相位平滑伪距原理，以及双向测距与时间同步系统对精度和实时性的要求，通过采用实验室的实测数据对DRTS载波相位平滑伪距算法其进行了研究和仿真。仿真结果表明，DRTS载波相位平滑前后的伪距误差有了很大程度的改善（在设定平滑长度M=300情况下，平滑后的伪距误差的均方根从原始的1.3652降低至0.9389），验证了该算法对提高双向测距与时间同步系统测量精度的有效性。同时针对系统中出现的伪码突发错误与周跳所引起的测距误差，通过采用上一次经过平滑后的测量值代替本次平滑值的办法进行修复，从而保证了系统的测量精度。经过实验分析，DRTS载波相位平滑伪距还存在这样的问题，如果选取的平滑长度较小时，平滑效果不明显；选取平滑长度较大时，效果虽然明显，但却牺牲了系统的实时性。因此在选取平滑长度时要在平滑效果与实时性之间要进行衡量和取舍。在本实验中，平滑长度选取在200~300之间时，既满足系统实时性又满足精度要求，为下一步DRTS中DSP的算法实现提供了理论依据。（2）双向测距与时间同步系统基于双向单程伪距测量机制，收发信机设备时延包含在了系统的测量值之中，，在很大程度上影响了系统的测距精度和性能。为此，在分析DRTS设备时延组成的基础上，针对系统提出了DRTS终端闭环自校方法，并对该设备时延校准方法的有效性进行了验证。结果表明，该DRTS终端闭环自校方法的准确度和精度均达到了纳秒量级，为双向测距与时间同步系统的下一步设计提供了有效的参考。
[Abstract]:With the development of mobile communication, global satellite navigation system and other scientific fields, the importance of precision ranging and time synchronization is becoming more and more prominent. In many fields of engineering and science, precise time synchronization is required. For example, high precision time synchronization of nanosecond or sub-nanosecond magnitude is required in all time laboratories around the world; satellite launch and measurement and control, And the atomic clocks of the test range need to be calibrated; between navigation satellites, between satellites and earth stations, between earth stations and earth stations need high precision time synchronization; in addition, autonomous formation of spacecraft, such as AFF, netting aircraft, etc. Precise baseline measurements and time synchronization are also required. Therefore, the study of bidirectional ranging and time synchronization technology is of great significance to the development of these fields. Based on the research on the methods of improving the accuracy of the bidirectional ranging and time synchronization system, this paper focuses on two techniques to improve the measurement accuracy, namely, carrier phase smoothing pseudo-range technique and equipment delay calibration technique. The main contents and results of this paper are as follows: This paper discusses how to improve the ranging accuracy of the system by improving the preprocessing algorithm of the original observation data from the point of view of the signal processing algorithm of the bidirectional ranging and time synchronization system (DRTS). According to the principle of carrier phase smoothing pseudo-range and the requirement of precision and real-time of bidirectional ranging and time synchronization system, the DRTS carrier phase smoothing pseudo-range algorithm is studied and simulated by using the measured data in the laboratory. The simulation results show that the pseudo-range error of DRTS carrier phase smoothing is greatly improved. The root mean square (RMS) of the smoothing pseudo-range error is reduced from 1.3652 to 0.9389, which verifies the effectiveness of the proposed algorithm in improving the measurement accuracy of the bidirectional ranging and time synchronization systems. At the same time, the error caused by pseudo-code burst and cycle slip is repaired by replacing the smoothing value with the previous smoothing value, so as to ensure the measurement accuracy of the system. Through the experimental analysis of DRTS carrier phase smoothing pseudo-range still exist such a problem, if the selected smoothing length is small, the smoothing effect is not obvious; when the selection of large smoothing length, the effect is obvious, but at the expense of the real-time of the system. Therefore, when selecting the smoothing length, it is necessary to measure and choose between the smoothing effect and the real time. In this experiment, when the smoothing length is between 200 and 300, it not only meets the real-time and precision requirements of the system, but also provides a theoretical basis for the implementation of the DSP algorithm in the next step of DRTS. 2) Bidirectional ranging and time synchronization system is based on bidirectional single-pass pseudo-range measurement mechanism. The delay of transceiver equipment is included in the measurement value of the system, which greatly affects the ranging accuracy and performance of the system. Based on the analysis of the delay components of DRTS devices, a closed loop self-calibration method for DRTS terminals is proposed, and the validity of the calibration method is verified. The results show that the accuracy and accuracy of the closed-loop self-calibration method for DRTS terminal are in the order of nanosecond, which provides an effective reference for the next step design of bidirectional ranging and time synchronization system.
【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】：硕士
【学位授予年份】：2014
【分类号】：TN919.34

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