Highly precise time and stable reference frequencies are fundamental requirements for space geodesy. Satellite laser ranging (SLR) is one of these techniques, which differs from all other applications like Very Long Baseline Interferometry (VLBI), Global Navigation Satellite Systems (GNSS) and finally Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) by the fact that it is an optical two-way measurement technique. That means that there is no need for a clock synchronization process between both ends of the distance covered by the measurement technique. Under the assumption of isotropy for the speed of light, SLR establishes the only practical realization of the Einstein Synchronization process so far. Therefore it is a powerful time transfer technique. However, in order to transfer time between two remote clocks, it is also necessary to tightly control all possible signal delays in the ranging process. This paper discusses the role of time and frequency in SLR as well as the error sources before it address the transfer of time between ground and space. The need of an improved signal delay control led to a major redesign of the local time and frequency distribution at the Geodetic Observatory Wettzell. Closure measurements can now be used to identify and remove systematic errors in SLR measurements.

中文翻译：

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相干本地时间在光学时间传递中的应用和卫星激光测距系统误差的量化

高精度的时间和稳定的参考频率是空间大地测量的基本要求。卫星激光测距 (SLR) 是其中一种技术，它不同于超长基线干涉测量 (VLBI)、全球导航卫星系统 (GNSS) 以及最终的多普勒轨道成像和卫星集成无线电定位 (DORIS) 等所有其他应用，因为它是一种光学双向测量技术。这意味着测量技术覆盖的距离的两端之间不需要时钟同步过程。在光速各向同性的假设下，SLR 建立了迄今为止爱因斯坦同步过程的唯一实际实现。因此，它是一种强大的时间传输技术。然而，为了在两个远程时钟之间传输时间，还必须严格控制测距过程中所有可能的信号延迟。本文讨论了时间和频率在 SLR 中的作用以及误差来源，然后才解决了地面和空间之间的时间传递问题。对改进信号延迟控制的需求导致了大地测量天文台 Wettzell 的本地时间和频率分布的重大重新设计。闭合测量现在可用于识别和消除 SLR 测量中的系统误差。对改进信号延迟控制的需求导致了大地测量天文台 Wettzell 的本地时间和频率分布的重大重新设计。闭合测量现在可用于识别和消除 SLR 测量中的系统误差。对改进信号延迟控制的需求导致了大地测量天文台 Wettzell 的本地时间和频率分布的重大重新设计。闭合测量现在可用于识别和消除 SLR 测量中的系统误差。