Delta-T: All Optical Time Tagging in Satellite Laser Ranging And Optical Delay Compensation For Very Long Baseline Interferometry Based On Ultra-Short Mode-Locked Laser

Delta-T：卫星激光测距中的全光时间标记和基于超短锁模激光器的超长基线干涉测量的光延迟补偿

• 批准号: 423159159
• 负责人: Professor Dr.-Ing. Ulrich Schreiber
• 金额: --
• 依托单位: Lehrstuhl für Geodäsie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/423159159?language=en
• 关键词: Delta; Optical; Time; Tagging; Satellite

Satellite Laser Ranging (SLR) is an advanced technology, which is used in the field of space geodesy for precise orbit determination. More recently SLR demonstrated its suitability for accurate time transfer between a ground station and the Jason 2 satellite in a low Earth orbit. While a single shot precision of less than 15 ps is typically achieved by several SLR systems, the respective obtained accuracy for the reconstruction of the satellite orbit is not better than 20 – 45 ps. This is caused by some fundamental short-comings of the current realization of the SLR technique, since the measurement is done in the optical domain and the time tagging in the microwave regime. In order to improve the accuracy of optical time transfer by reducing systematic errors to less than 10 ps, we propose to use a delay compensated fs-pulse laser (available on the observatory) to move the complete time tagging process of the laser ranging technique entirely into the optical domain and exploit the fact that mode-locked fs-pulse lasers have ultra-low noise in the optical and microwave regime simultaneously. This will significantly improve the time transfer precision and accuracy between the Wettzell Laser Ranging System on the ground and the Atomic Clock Ensemble in Space (ACES), which is prepared for the operation on the International Space Station (ISS). Similar considerations apply for the Very Long Baseline Interferometry (VLBI). Long cables, subject to squeezing and stretching when the antenna is in motion and temperature sensitive amplifier and mixer delays are causing systematic errors. These can only partially be absorbed by clock adjust-ments and modeling tropospheric delay corrections. Therefore we propose to use the same two-way optical delay compensated time and frequency distribution concept also for the VLBI in order to obtain a stable unambiguous system reference as well as an ultra-wideband fs pulse laser based phase calibration for the new VGOS systems, covering also the Ka band. Last but not least we shall demonstrate the reduction of systematic measurement errors in a closure measurement concept based on a common actively stabilized timebase.

卫星激光射程（SLR）是一种先进的技术，用于精确轨道测定的空间测量领域。最近，SLR证明了其适合于在低地轨道中的地面站和Jason 2卫星之间进行准确的时间转移的适用性。虽然通常通过几个SLR系统实现了小于15 ps的单个射击精度，但各自的重建卫星轨道的准确性不高于20 - 45 PS。这是由于SLR技术当前实现的一些基本短暂的作用，因为该测量是在光学域中完成的，并且在微波炉状态下进行了时间标记。为了通过将系统误差减少到10 ps来提高光学时间传输的准确性，我们建议使用延迟补偿的FS-pulse激光器（可在观察值中获得）将激光范围技术的完整时间标记过程完全转移到光学领域中，并简单地探索了模式的FS-Pulse-pulse-lasime sive and optical offical offical off the Ultra nose and optir and optic and optir and off the Ultra nose shise oft the Ultra sy.这将显着提高地面上的Wettzell激光范围系统与太空中的原子钟集合（ACE）之间的时间传输精度和准确性，该集合已准备好用于国际空间站（ISS）的操作。类似的考虑因素适用于非常长的基线干涉法（VLBI）。长电缆，当天线在运动和温度敏感的放大器和混合器延迟时，可能会挤压和拉伸，导致系统误差。这些只能通过时钟调整和对流层延迟校正来部分吸收。因此，我们建议对VLBI使用相同的双向光学延迟补偿时间和频率分布概念，以获得新的VGOS系统的稳定的明确系统参考以及超宽带FS FS脉冲激光器的相位校准，还涵盖KA频段。最后但并非最不重要的一点是，我们将基于通常正在主动稳定的时态的封闭测量概念中的系统测量误差减少。