The Center for Orbit Determination in Europe (CODE) is contributing to the most recent reprocessing effort of the International GNSS Service (IGS) with a triple-system solution including GPS (since 1994), GLONASS (since 2002) and Galileo (since 2013). Several model improvements with respect to the operational processing scheme have been implemented and applied for the reprocessing effort: The first group of improvements is related to the update of IERS-related models (mean pole and high-frequency pole models). The second group is related to the inclusion of Galileo with calibrated receiver and satellite antennas. The consistency of the scale for the ground station coordinates was verified based on the estimation of GNSS-specific coordinate biases. It turned out that currently widely used GPS-based receiver antenna calibrations do compensate (just by chance) a discrepancy in the scale when using the pre-launch satellite antenna calibrations for Galileo.

Furthermore and third, a long-arc solution over three days is introduced where in particular empirical velocity changes are rescheduled with respect to the operational processing chain at CODE. Instead of simply estimating them every 12 h they are now setup at orbit midnight. This rescheduling reduces the size of orbit misclosures by 10% for GPS and 15% for Galileo; no improvement for GLONASS was observed because there the orbit misclosures are dominated by other effects. Another feature applied for the first time in this reprocessing series is to downweight the observations of a number of GPS satellites with a reduced stability in the attitude control around the year 2000. This change in the analysis strategy reduces the noise level of GNSS-derived products, e.g., of the Earth rotation series.

Even if the article is focusing on the reprocessing series as provided by the CODE analysis center many of the conclusions may also be applied to other GNSS series in future.

欧洲轨道测定中心 (CODE) 正在为国际 GNSS 服务 (IGS) 的最新后处理工作做出贡献，其三系统解决方案包括 GPS（自 1994 年）、GLONASS（自 2002 年）和伽利略（自 2013 年） . 针对操作处理方案的若干模型改进已实施并应用于再处理工作：第一组改进与 IERS 相关模型（平均极点和高频极点模型）的更新有关。第二组与包含校准接收器和卫星天线的伽利略有关。基于对 GNSS 特定坐标偏差的估计，验证了地面站坐标比例尺的一致性。

此外，第三，引入了一个超过三天的长弧解决方案，特别是根据 CODE 的操作处理链重新安排经验速度变化。现在不是每 12 小时简单地估计它们，而是在午夜轨道上设置它们。这种重新安排将 GPS 和伽利略的轨道错合减少了 10% 和 15%；没有观察到 GLONASS 的改进，因为在那里轨道不闭合主要受其他影响。本次再处理系列中首次应用的另一个功能是降低了 2000 年左右姿态控制稳定性降低的多颗 GPS 卫星的观测值。这种分析策略的变化降低了 GNSS 衍生产品的噪声水平，例如，地球自转系列。

即使文章关注的是CODE分析中心提供的再处理系列，很多结论将来也可能适用于其他GNSS系列。