Strengthening the GNSS based kinematic positioning of low Earth orbiters for gravity field determination (B03)

在第一个资助期内，B03研究了基于模拟和真实全球定位系统数据确定低地球轨道飞行器卫星运动轨道的新方法。第一个重点是接收器时钟建模的概念，这导致实际数据分析的3D RMS改进了29%。第二个主题是虚拟接收器，它结合了来自多个GNSS天线的数据，将径向分量的观测几何强化了43%。这一概念将在第二个资助期得到进一步研究。此外，还将详细研究基于GPS多普勒观测的直接速度估计及其对重力场恢复的影响。

Within the first funding period, B03 investigated new approaches for kinematic orbit determination of low Earth orbiter satellites based on simulated and real GPS data. The first focus was on the concept of receiver clock modelling, which lead to an improved 3D RMS of 29 % for real data analysis. The second topic is the virtual receiver, which combines data from multiple GNSS antennas and strengthens the observation geometry for the radial component by 43 %. This concept will be further investigated in the second funding period. In addition, the direct velocity estimation based on GPS Doppler observations and its impact on gravity field recovery will be studied in detail.