The International Laser Ranging Service (ILRS) provides weekly solutions for coordinates of Satellite Laser Ranging (SLR) stations coordinates, geocenter coordinates, as well as Earth rotation parameters with a daily resolution. The ILRS standard solution is an important contribution to the International Terrestrial Reference Frame (ITRF). As of today, it is derived from SLR observations to the pairs of LAGEOS and Etalon satellites exclusively. In this paper, the effect of altering the tracking strategy for the LAGEOS and Etalon satellites on the weekly ILRS standard solution is studied. This is done by simulating various tracking scenarios and by comparing the parameters of the solutions for each scenario. In particular, the focus lies on redistributing observation time between the LAGEOS and Etalon satellites as a possible optimization for the tracking scheduling. By this, the current tracking capability of each station is taken into account with no change of the overall tracking activity to LAGEOS and Etalon. It is shown that the quality of the solution for the ITRF-relevant parameters is not significantly degraded when reducing the number of observations to LAGEOS by up to 20% with respect to the number of available normal points in 2016. The vacant tracking capability obtained from the reduction of LAGEOS observations may be used to increase the number of measurements to Etalon by a factor of three. This leads to nearly 10% improvement of the recovery of Earth rotation parameters within the combined LAGEOS–Etalon solution. With our study, we contribute to the ongoing discussions regarding tracking strategies for SLR stations within the ILRS. In particular, the stations could adjust their individual tracking priorities according to these results in the future without major investments or the need for new infrastructure.

中文翻译：

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模拟 LAGEOS 和 Etalon 卫星的跟踪场景

国际激光测距服务 (ILRS) 每周提供卫星激光测距 (SLR) 站坐标、地心坐标以及具有每日分辨率的地球自转参数的解决方案。ILRS 标准解决方案是对国际陆地参考框架 (ITRF) 的重要贡献。截至今天，它仅源自对 LAGEOS 和标准具卫星对的 SLR 观测。本文研究了改变 LAGEOS 和 Etalon 卫星跟踪策略对每周 ILRS 标准解的影响。这是通过模拟各种跟踪场景并通过比较每个场景的解决方案参数来完成的。特别是，重点在于重新分配 LAGEOS 和标准具卫星之间的观测时间，作为跟踪调度的可能优化。这样，每个站点的当前跟踪能力都被考虑在内，而对 LAGEOS 和标准具的整体跟踪活动没有变化。结果表明，相对于 2016 年可用法线点的数量，将 LAGEOS 的观测数量减少多达 20% 时，ITRF 相关参数的解的质量没有显着下降。 LAGEOS 观测值的减少可用于将标准具的测量次数增加三倍。这导致 LAGEOS-标准具组合解决方案中地球自转参数的恢复提高了近 10%。通过我们的学习，我们为正在进行的关于 ILRS 内 SLR 站跟踪策略的讨论做出了贡献。特别是，这些站点可以在未来根据这些结果调整各自的跟踪优先级，而无需进行大量投资或需要新的基础设施。