基于GEO通信卫星的转发式共视授时方法

发布时间：2018-04-09 19:01

本文选题：转发式共视授时　切入点：双向卫星时间比对　出处：《中国科学院研究生院（国家授时中心）》2013年硕士论文

【摘要】：现有的远距离高精度时间传递技术主要有GPS共视和卫星双向时间比对（Two-WaySatellite Time and Frequency Transfer, TWSTFT）。GPS伪码共视的精度较低，TWSTFT的设备昂贵，其在需要高精度时间标准的工程实践中的应用受到限制。为解决上述问题本文提出了一种使用GEO通信卫星进行转发式共视授时的方法（Common-View time transfer with Transfer mode, TCV）。该方法独立于GNSS系统和典型TWSTFT系统，可以实现在单颗GEO卫星的覆盖区域内，将守时实验室的高精度标准时间传递给用户。守时实验室需配备接收和发射设备，用户仅需配备接收设备。守时实验室将以其主钟为参考的伪码测距信号向GEO卫星发射，GEO卫星转发该信号，，守时实验室和用户同时接收经卫星转发的信号并进行伪距测量，解算用户与守时实验室之间的相对钟差，实现转发式共视授时。守时实验室和用户均使用增益高、信噪比好、有效抗多径的抛物面天线作为接收天线。中国科学院国家授时中心保持有中国的国家标准时间UTC(NTSC)，本文使用C波段双向卫星时间频率比对系统（Two Way Satellite Time and Frequency Transfer with C band,TW(C)）进行试验；在位于临潼的国家授时中心、长春人卫站和喀什站各放置两套TW(C)设备，分别进行两次试验；由国家授时中心发射伪码测距信号作为主站，长春和喀什两站仅使用TW(C)设备的接收功能模拟用户接收机。终端设备型号为德国TimeTech公司的SATRE MODEM，扩频码速率为20MChips，试验卫星为中星10号GEO通信卫星（星下点位于东经110.5度）。该方法要求事先确定接收机的天线坐标和GEO卫星的轨道。轨道数据来自中国科学院国家授时中心转发式测定轨系统，精度为米级水平，在星地连线上精度达到分米级。试验中以卫星双向时间比对的结果作为真值，评判转发式共视授时的精度。数据处理中除修正Sagnac效应、电离层时延、对流层时延等常规影响外，还修正了固体潮影响。固体潮会引起分米级的几何路径时延变化，考虑固体潮影响会使两种方法互差的标准差最多减少0.11纳秒。试验结果比较表明：转发式共视授时方法是一种可行的远距离高精度时间传递方法，在所需数据完整的前提下，其结果与TWSTFT结果的吻合程度要优于0.5ns，显著优于GPS远距离伪码共视比对精度(3~5ns)。
[Abstract]:The existing long distance and high precision time transfer techniques mainly include GPS common view and two way satellite time comparison. The TWSTFT).GPS pseudo-code common viewing equipment is expensive, and its application in engineering practice which needs high precision time standard is limited.In order to solve the above problems, this paper presents a method of forwarding co-view timing using GEO communication satellite, which is composed of Common-View time transfer with Transfer mod.This method is independent of the GNSS system and the typical TWSTFT system. It can transmit the high precision standard time of the punctuality laboratory to the user in the coverage area of a single GEO satellite.Time-keeping laboratories need to be equipped with receiving and transmitting equipment, and users only need to be equipped with receiving equipment.The punctuality laboratory transmits the pseudo-code ranging signal referred to its main clock to the GEO satellite by transmitting the signal. The punctuality laboratory and the user simultaneously receive the signals transmitted by the satellite and conduct pseudo-range measurements.The relative clock difference between the user and the punctuality laboratory is calculated, and the forwarding common view time is realized.High gain, good signal-to-noise ratio (SNR) and effective multipath resistant paraboloid antenna are used as receiving antennas in punctuality laboratories and users.The National time Service Center of the Chinese Academy of Sciences maintains China's national standard time UTC / NTSCN. In this paper, two Way Satellite Time and Frequency Frequency Transfer with TWWNs are used to carry out experiments at the National time Service Center in Lintong, which is located in Lintong.Changchun and Kashi stations each put two sets of TWN C) equipment to carry out two tests respectively. The National time Service Center transmits pseudo-code ranging signal as the main station, and Changchun and Kashi stations only use the receiving function of TWCU equipment to simulate the user receiver.The terminal equipment model is SATRE MODEM of TimeTech Company of Germany, the spread spectrum code rate is 20m Chips. the test satellite is Zhongxing 10 GEO communication satellite (the lower point is 110.5 degrees east longitude).This method requires the antenna coordinates of the receiver and the orbit of the GEO satellite to be determined in advance.The orbit data are obtained from the National time Service Center of the Chinese Academy of Sciences (CAS). The accuracy of the orbit determination system is meter level, and the accuracy on the satellite to earth line reaches the decimeter level.In the experiment, the result of satellite bidirectional time comparison is taken as the true value to judge the accuracy of forwarding common view time.In data processing, the effects of Sagnac effect, ionospheric delay and tropospheric delay are corrected as well as the effect of solid tide.Considering the influence of solid tide, the standard deviation of the two methods can be reduced by 0.11 nanoseconds.The experimental results show that the forward common view time delivery method is a feasible method for long distance and high precision time transmission.The agreement between the result and the TWSTFT result is better than 0.5 ns, and is significantly better than that of GPS long distance PN code.
【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】：2013
【分类号】：P228.4

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