We derive an empirical model of the sub-daily polar motion (PM) based on the multi-GNSS processing incorporating GPS, GLONASS, and Galileo observations. The sub-daily PM model is based on 3-year multi-GNSS solutions with a 2 h temporal resolution. Firstly, we discuss differences in sub-daily PM estimates delivered from individual GNSS constellations, including GPS, GLONASS, Galileo, and the combined multi-GNSS solutions. Secondly, we evaluate the consistency between the GNSS-based estimates of the sub-daily PM with three independent models, i.e., the model recommended in the International Earth Rotation and Reference Systems Service (IERS) 2010 Conventions, the Desai–Sibois model, and the Gipson model. The sub-daily PM estimates, which are derived from system-specific solutions, are inherently affected by artificial non-tidal signals. These signals arise mainly from the resonance between the Earth rotation period and the satellite revolution period. We found strong spurious signals in GLONASS-based and Galileo-based results with amplitudes up to 30 µas. The combined multi-GNSS solution delivers the best estimates and the best consistency of the sub-daily PM with external geophysical and empirical models. Moreover, the impact of the non-tidal spurious signals in the frequency domain diminishes in the multi-GNSS combination. After the recovery of the tidal coefficients for 38 tides, we infer better consistency of the GNSS-based empirical models with the new Desai–Sibois model than the model recommended in the IERS 2010 Conventions. The consistency with the Desai–Sibois model, in terms of the inter-quartile ranges of tidal amplitude differences, reaches the level of 1.6, 5.7, 6.3, 2.2 µas for the prograde diurnal tidal terms and 1.2/2.1, 2.3/6.0, 2.6/5.5, 2.1/5.1 µas for prograde/retrograde semi-diurnal tidal terms, for the combined multi-GNSS, GPS, GLONASS, and Galileo solutions, respectively.

中文翻译：

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来自 GPS、GLONASS 和 Galileo 的次日极地运动

我们基于结合 GPS、GLONASS 和伽利略观测的多 GNSS 处理推导出次日极移 (PM) 的经验模型。次日 PM 模型基于具有 2 小时时间分辨率的 3 年多 GNSS 解决方案。首先，我们讨论从单个 GNSS 星座（包括 GPS、GLONASS、Galileo 和组合的多 GNSS 解决方案）提供的次日 PM 估计值的差异。其次，我们评估了基于 GNSS 的亚日 PM 估计值与三个独立模型之间的一致性，即国际地球自转和参考系统服务 (IERS) 2010 公约中推荐的模型、Desai-Sibois 模型和吉普森模型。来自系统特定解决方案的次日 PM 估计值本质上受到人工非潮汐信号的影响。这些信号主要来自地球自转周期和卫星公转周期之间的共振。我们在基于 GLONASS 和基于伽利略的结果中发现了幅度高达 30 µas 的强杂散信号。组合的多 GNSS 解决方案通过外部地球物理和经验模型提供了最佳估计和次日 PM 的最佳一致性。此外，在多 GNSS 组合中，频域中非潮汐杂散信号的影响减弱。在恢复 38 个潮汐的潮汐系数后，我们推断基于 GNSS 的经验模型与新的 Desai-Sibois 模型的一致性比 IERS 2010 公约中推荐的模型更好。与 Desai-Sibois 模型的一致性，在潮汐幅度差异的四分位间距方面，达到了 1.6、5.7、6.3 的水平，