卫星高度角对GPS单向时间传递性能的影响研究

GPS单向时间传递可用于完成本地时间频率参考的校准及向协调世界时的高精度溯源。然而，卫星高度角的变化对时间频率传递的性能会产生一定的影响。概述了GPS卫星单向时间传递的基本原理，分析了不同卫星高度角对时间频率传递性能产生影响的原因，给出了时间频率传递性能的评估方法。最后，通过实验测试GPS卫星高度角变化对时间频率传递性能的影响，给出了实验结果并进行了分析。实验结果表明，随着卫星截止高度角的增加，GPS单向时间频率传递的性能将会提高，但是可视卫星的数量会减少。工程应用中，如果对时间频率传递长期稳定性要求较高，可将截至高度角设为25°；如只对短期稳定性要求较高，可将截止高度角设为5°。

Research on GPS One-way Time Transfer Performance Impacted by Angle of Satellite Elevation

GPS one-way time transfer is a method to achieve local time and frequency reference calibration and traceability to Coordinated Universal Time（ UTC）. However,time and frequency transfer performance is impacted due to the change of GPS satellite elevation angle. The basic principle of GPS one-way time transfer is generally described,and the reason why the GPS satellite angle will impact the performance of time and frequency transfer is also analyzed. Furthermore,the assessment method of time and frequency transfer performance is given. Finally,the impact on the performance of time and frequency transfer is tested according to the designed experiment. Moreover,the experiment results are given and analyzed. The experiment results indicate that GPS time and frequency transfer performance will be improved while the number of visible satellite decreases as the increase of satellite elevation mask. In the engineering field,the elevation mask should be set as 25°if the long-term stability is required in time and frequency transfer; while the elevation mask should be set as 5°if just the short-term stability is required.