Consistent dynamic satellite reference frames and terres-trial geodetic datum parameters

该项目的目的是利用全球导航卫星系统、激光测距仪和DORIS现有观测数据的优势，对轨道高度、倾角和跟踪技术各不相同的单个卫星和共同观测卫星进行观测，从而实现高精度动态参照基准。工作的重点是改进全球大地测量基准的实现，以及为地球参照框架的基准定义提出新的概念。与前一个项目相比，特别是将包括通过至少两种技术观测的低地球轨道卫星。这些类型的卫星充当移动的共址站点，并提供具有非常不同和不断变化的观测几何的观测。因此，联合轨道确定将大大加强参照系解，预计该解对大地基准参数的敏感性将大大增加。进行了补充模拟研究，以了解和评估对基准参数非常敏感的卫星和台站配置。模拟使它能够研究新的轨道和观测类型。将通过扩展模拟研究地球同步导航卫星以及DORIS相位观测和导航卫星之间的精确星间测距链路对参考框架稳定性的贡献。该项目的成果是时代和长期的参考框架，具有当今可以达到的最高精度的数据实现。此外，还将就今后如何通过新的卫星飞行任务和优化观测站网络以及使用新的观测类型来改进地面参照基准的数据实现提出建议。

The aim of the project is the realization of high-precision dynamic reference frames by exploiting the strengths of the available GNSS, SLR and DORIS observations to individual and commonly observed satellites that are characterized by different orbit heights, inclinations and tracking techniques. The focus of the work is the improved realisation of the global geodetic datum as well as on the development of novel concepts for the datum definition of the terrestrial reference frames. Compared to the previous project, in particular low Earth orbiting satellites observed by at least two techniques will be included. These type of satellites act as moving co-location sites and provide observations with very different and changing observation geometries. Thus, combined orbit determination will strengthen the reference frame solution significantly and it is expected that the sensitivity of the solution with respect to the geodetic datum parameters will increase strongly. Complementary simulation studies are performed in order to realize and assess satellite and station configurations which are very sensitive to the datum parameters. Simulations allow it in addition to investigate new orbit and observation types. The contribution of geosynchronous navigation satellites as well as DORIS phase observations and precise inter-satellite ranging links between navigation satellites to the stability of the reference frame will be investigated with extended simulations. The outcomes of the project are epoch and long-term reference frames with a datum realization of the highest accuracy which can be reached today. Furthermore, recommendations will be made, how the datum realization of the terrestrial reference frames can be improved in future by new satellite missions and optimised observing station networks but also by using new observation types.