Geocenter variations derived from a combined processing of LEO- and ground-based GPS observations
Geocenter variations derived from a combined processing of LEO- and ground-based GPS observations
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DOI：
10.1007/s00190-017-0997-y
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发表时间：
2017-01
影响因子：
4.4
通讯作者：
Benjamin Männel;M. Rothacher
中科院分区：
文献类型：
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作者：
Benjamin Männel;M. Rothacher
由国际全球导航卫星系统服务组织全球跟踪网络提供的全球导航卫星系统观测（IGS，Dow等人，J Geod 83（3）：191-198，2009年）在实现一个独特的地面参照系方面发挥着重要作用，该参照系的准确度足以允许对地球系统进行详细监测。将这些地面数据与低地球轨道飞行器上高质量双频接收器跟踪的全球定位系统观测数据相结合，是进一步改进地球参考框架的实现和对地心坐标、全球定位系统卫星轨道和地球自转参数的估计的一种有希望的方法。为了评估改进地心坐标的范围，我们在3年的时间间隔（2010-2012年）内处理了53个全球分布和稳定的IGS站以及4个LEO（GRACE-A，GRACE-B，OSTM/Jason-2和GOCE）的网络。为了确保完全一致的解决办法，对地面站和低地球轨道的零差相位观测值进行了共同的最小二乘调整，估计了所有相关参数，如全球定位系统和低地球轨道轨道、台站坐标、地球自转参数和地心运动。我们提出了显着的影响，个别低地球轨道和所有四个低地球轨道的组合上的地心坐标。由于将一个低地球轨道纳入仅地面的解决方案，形式误差减少了约20%，而在具有四个低地球轨道的解决方案中，低地球轨道的具体特征显着减少。我们比较推导出的地心坐标w.r.t. LAGEOS结果和基于GPS和SLR数据的外部解决方案。我们发现，所有组件的振幅很好的协议，但是，在x和z方向的相位不同意。
GNSS observations provided by the global tracking network of the International GNSS Service (IGS, Dow et al. in J Geod 83(3):191–198, 2009) play an important role in the realization of a unique terrestrial reference frame that is accurate enough to allow a detailed monitoring of the Earth’s system. Combining these ground-based data with GPS observations tracked by high-quality dual-frequency receivers on-board low earth orbiters (LEOs) is a promising way to further improve the realization of the terrestrial reference frame and the estimation of geocenter coordinates, GPS satellite orbits and Earth rotation parameters. To assess the scope of the improvement on the geocenter coordinates, we processed a network of 53 globally distributed and stable IGS stations together with four LEOs (GRACE-A, GRACE-B, OSTM/Jason-2 and GOCE) over a time interval of 3 years (2010–2012). To ensure fully consistent solutions, the zero-difference phase observations of the ground stations and LEOs were processed in a common least-squares adjustment, estimating all the relevant parameters such as GPS and LEO orbits, station coordinates, Earth rotation parameters and geocenter motion. We present the significant impact of the individual LEO and a combination of all four LEOs on the geocenter coordinates. The formal errors are reduced by around 20% due to the inclusion of one LEO into the ground-only solution, while in a solution with four LEOs LEO-specific characteristics are significantly reduced. We compare the derived geocenter coordinates w.r.t. LAGEOS results and external solutions based on GPS and SLR data. We found good agreement in the amplitudes of all components; however, the phases inx- andz-direction do not agree well.