Galileo satellites are equipped with laser retroreflector arrays for satellite laser ranging (SLR). In this study, we develop a methodology for the GNSS-SLR combination at the normal equation level with three different weighting strategies and evaluate the impact of laser observations on the determined Galileo orbits. We provide the optimum weighting scheme for precise orbit determination employing the co-location onboard Galileo. The combined GNSS-SLR solution diminishes the semimajor axis formal error by up to 62%, as well as reduces the dependency between values of formal errors and the elevation of the Sun above the orbital plane—the β angle. In the combined solution, the standard deviation of the SLR residuals decreases from 36.1 to 29.6 mm for Galileo-IOV satellites and |β|> 60°, when compared to GNSS-only solutions. Moreover, the bias of the Length-of-Day parameter is 20% lower for the combined solution when compared to the microwave one. As a result, the combination of GNSS and SLR observations provides promising results for future co-locations onboard the Galileo satellites for the orbit determination, realization of the terrestrial reference frames, and deriving geodetic parameters.

伽利略卫星配备了激光后向反射器阵列，用于卫星激光测距（SLR）。在这项研究中，我们为正态方程级别的GNSS-SLR组合开发了一种方法，具有三种不同的加权策略，并评估了激光观测对确定的伽利略轨道的影响。我们使用伽利略号上的同一位置为精确的轨道确定提供最佳的加权方案。组合的GNSS-SLR解决方案可将半长轴形式误差减少多达62％，并减少形式误差值与太阳在轨道平面上方的仰角（β角）之间的依赖性。在组合解决方案中，对于伽利略-IOV卫星，SLR残差的标准偏差从36.1降低至29.6 mm，β与仅GNSS的解决方案相比|> 60°。此外，与微波相比，组合溶液的日长参数偏差要低20％。结果，GNSS和SLR观测的结合为伽利略卫星上未来的同地定位，确定轨道，实现地面参考系和推导大地测量参数提供了可喜的结果。