European Space Agency, Technical Directorate, Noordwijk, The Netherlands.
IEEE Trans Ultrason Ferroelectr Freq Control. 2010 Mar;57(3):738-45. doi: 10.1109/TUFFC.2010.1472.
The Galileo In-Orbit Validation Element (GIOVE) is an experiment led by the European Space Agency (ESA) aimed at supporting the on-going implementation of Galileo, the European global navigation satellite system (GNSS). Among the objectives of the GIOVE Mission are the validation and characterization of the on-board clock technologies. The current baseline technologies for on-board clocks are the rubidium atomic frequency standard (RAFS) and the passive hydrogen maser (PHM). Both technologies have been validated and qualified on ground and are now being further validated in a representative in-orbit environment aboard 2 spacecrafts, GIOVE-A and GIOVE-B. This paper presents the results obtained in the frame of the GIOVE experimentation. The behavior and performances of the clock technologies on board both spacecrafts has been investigated and analyzed in terms of operation, frequency stability, and clock prediction error after more than 3 years of operation for GIOVE-A and almost one year for GIOVE-B. In addition, relativistic frequency shifts of GIOVE spacecrafts have been investigated.
伽利略在轨验证单元（GIOVE）是由欧洲航天局（ESA）领导的一项实验，旨在支持正在进行的伽利略计划，这是一个欧洲全球导航卫星系统（GNSS）。GIOVE 任务的目标之一是验证和描述星载时钟技术。目前，星载时钟的基准技术是铷原子频率标准（RAFS）和被动氢 maser（PHM）。这两种技术都已经在地面上进行了验证和合格测试，现在正在两颗航天器，GIOVE-A 和 GIOVE-B 上的一个具有代表性的轨道环境中进行进一步验证。本文介绍了在 GIOVE 实验框架内获得的结果。对这两颗航天器上的时钟技术的性能和行为进行了调查和分析，包括操作、频率稳定性以及 GIOVE-A 运行 3 年多和 GIOVE-B 运行近 1 年后的时钟预测误差。此外，还研究了 GIOVE 航天器的相对论频率漂移。
