中文摘要：

北斗卫星导航系统（BDS）于2012年底开始提供区域服务，进行BDS星载原子钟的长期性能分析，对于系统性能的评估、卫星钟差的确定与预报等具有重要的作用。本文基于3年的多星定轨联合解算的BDS精密卫星钟数据，利用改进的中位数方法进行数据预处理，分析了卫星钟差数据的特点，使用卫星钟差二次多项式拟合模型分析了卫星钟的相位、频率、频漂及钟差模型噪声的长期变化特性，根据频谱分析的方法分析了卫星钟差的周期特性，采用重叠哈达玛方差计算并讨论了卫星钟的频率稳定性。综合上述方法及其试验结果较为全面地分析和评估了BDS星载原子钟的长期性能，得到结论：在噪声特性和钟漂特性方面，MEO卫星钟的性能最好，其次是IGSO卫星钟，最差的是GEO卫星钟，所有卫星钟噪声水平和频漂的均值分别为0.677 ns和1.922×10-18；多星定轨条件下的北斗卫星钟差存在显著的周期项，其主周期分别近似为对应卫星轨道周期的1/2倍或1倍；BDS星载原子钟频率稳定度的平均值为1.484×10-13。

英文摘要：

BeiDou Navigation Satellite System （BDS） has begun to provide regional services since the end of 2012. It plays an important role in analyzing the long-term performance of BDS satellite clocks in evaluating the performance of the whole system, determining and predicting satellite clock bias （SCB） etc. Precise satellite clock data products derived from multi-satellite orbit determination are used to conduct the performance analysis of BDS satellite clocks. Specifically, the characteristics of SCB data are discussed by using a proposed modified median absolute deviation （MAD） to preprocess original SCB data. Long-term variations of satellite clocks＇ phase, frequency, frequency drift and model noise level are analyzed based on the quadratic polynomial SCB model. Frequency stability of BDS satellite clocks is calculated and discussed based on Overlapping Hadamard Variance. Periodicity of BDS SCB is analyzed by using spectral analysis method. Integrating the above mentioned discussions and corresponding experiment results, the long-term performance of BDS satellite clocks is relatively comprehensively evaluated and analyzed. In addition, some valuable conclusions are obtained. For example, in the aspects of noise characteristics and clock drift, the performance of MEO satellite clocks is the best, followed by the IGSO satellite clocks, and the GEO satellite clocks＇ performance is the worst. The average values of noise level and frequency drift of BDS satellite clocks are respectively 0.677 ns and 1.922×10-18. There are also obvious periodic terms in BDS SCB data derived from multi-satellite orbit determination and their primary periods are approximate equal or one-half to the corresponding satellite orbit periods. The average value of frequency stability of BDS satellite clocks is 1.484×10-13.