基于条件平差的卫星双向时间传递链路性能优化方法

卫星双向时间传递(Two-Way Satellite Time and Frequency Transfer, TWSTFT)是目前精度最高的时间传递方法之一,同时也是参与国际原子时计算的守时实验室之间比较原子时尺度的一种主要方法.提高TWSTFT链路的短期稳定度,降低周日效应对链路时间传递结果的影响,对优化TAI (International Atomic Time)的性能具有现实意义.提出了一种基于条件平差的TWSTFT链路性能优化方法,先依据TWSTFT链路测量噪声水平与谱分析结果建立TWSTFT链路性能优化网络(简称优化网络),再根据优化网络中各链路测量噪声分析结果设置权系数阵,建立条件平差模型.选取亚太地区的中国计量科学研究院(National Institute of Metrology, NIM)-中国科学院国家授时中心(National Time Service Center, NTSC)卫星双向时间传递链路作为待优化链路,以NTSC、NIM以及德国联邦物理技术研究所(Physikalisch-Technische Bundesanstalt,PTB)之间的TWSTFT链路组成优化网络,对优化网络的组网方法和条件平差模型进行实验验证.结果表明,平差后待优化链路短期稳定度得到了改善,同时其受周日效应的影响降低了约24.6%.使用该方法,能够有效提高待优化链路的时间传递性能.

Performance Optimization Method of Two-Way Satellite Time and Frequency Transfer Link based on Conditional Adjustment

Two-Way Satellite Time and Frequency Transfer (TWSTFT) is one of the time transfer methods with the highest accuracy at present, and it is also a main method to compare the atomic time scale among the time-keeping laboratories participating in the international atomic time calculation. Improving the short-term stability of TWSTFT link and reducing the influence of Sunday effect on the link time transfer result have practical significance for optimizing the performance of TAI (International Atomic Time). In this paper, a method of TWSTFT link performance optimization based on condition adjustment is proposed. Firstly, the TWSTFT link performance optimization network (hereinafter referred to as the optimization network) is established according to the noise level and spectrum analysis results of TWSTFT link short-term stability measurement, and then the weight coefficient matrix is set according to the noise analysis results of each link short-term stability measurement in the optimization network to establish the condition adjustment model. The satellite two-way time transfer link of National Institute of Metrology (NIM) - National Time Service Center (NTSC) of Chinese Academy of Sciences in Asia Pacific region is selected as the link to be optimized, and the TWSTFT link among NTSC, NIM, and Physikalisch-Technische Bundesanstalt (PTB) is used to compose the optimized network. The networking method and condition adjustment model are verified. The results show that the short-term stability of the link to be optimized after adjustment is improved, and it is reduced by about 24.6% due to the influence of Sunday effect. Using this method, the time transfer performance of the link to be optimized can be improved effectively.