The earth rotation parameters (ERPs) are time-variable global geodetic parameters with a purely geophysical origin. Theoretically, the estimates of these parameters should be independent of the satellite constellation used in GNSS processing. Nonetheless, clear differences in the time series of ERPs are noticed when using different GNSS constellations. In this study, GPS, GLONASS, and Galileo estimates of ERP have been extensively evaluated in search of system-specific signals. Some of the processing details, such as modeling of the direct solar radiation pressure and length of the orbital arc, also have an impact on the ERP estimates. The GPS-based polar motion estimates are of better quality than those based on GLONASS and Galileo, which are susceptible to deficiencies in the orbit modeling. On the other hand, we observe a systematic bias of GPS-based length-of-day (LoD) with respect to the IERS-C04-14 values with a mean offset of − 22.4 µs/day. The Galileo-based solutions are almost entirely free of this issue. The extension of the orbital arc in the GNSS processing from 1 to 3 days is superior for the quality of the ERPs, especially for pole coordinate rates and LoD. The spurious signals inherently influence the Galileo-based and GLONASS-based ERPs at the frequencies which arise from the resonance between the satellite revolution period and earth rotation, e.g., 3.4 days for Galileo and 3.9 days for GLONASS. These and the draconitic signals overshadow the GNSS-based ERP estimates. Although all the system-specific solutions are affected by the artificial signals, the combination of different GNSS mitigates most of the uncertainties and improves the ERP results.

中文翻译：

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GPS，GLONASS和Galileo推导的地球自转参数中特定于系统的系统误差

地球自转参数（ERP）是时变的全球大地测量参数，具有纯粹的地球物理起源。从理论上讲，这些参数的估计应独立于GNSS处理中使用的卫星星座。但是，使用不同的GNSS星座图时，会注意到ERP的时间序列存在明显差异。在这项研究中，已广泛评估了GPS，GLONASS和Galileo对ERP的估计，以查找系统特定的信号。一些处理细节，例如对太阳直接辐射压力和轨道弧长度的建模，也会对ERP估算产生影响。基于GPS的极地运动估计比基于GLONASS和Galileo的极地质量估计质量更高，后者容易受到轨道建模的影响。另一方面，我们观察到相对于IERS-C04-14值，基于GPS的日长（LoD）出现系统性偏差，平均偏差为-22.4 µs / day。基于Galileo的解决方案几乎完全没有这个问题。GNSS处理中的轨道弧从1天延长到3天，对于ERP的质量而言尤其出色，尤其是极坐标速率和LoD。杂散信号固有地影响基于伽利略和基于GLONASS的ERPs，其频率来自卫星旋转周期与地球自转之间的共振，例如Galileo为3.4天，GLONASS为3.9天。这些和严峻的信号掩盖了基于GNSS的ERP估算。尽管所有系统特定的解决方案都受到人工信号的影响，