SLR data quality analysis and assessment based on zero-difference kinematic orbit of GRACE satellites

In this paper, we use SLR normal point observations provided by EDC to validate AIUB zero-difference kinematic orbit of GRACE satellites. By selecting 4 representative SLR sites, they are analyzed in detail from the regularity of observed elevation angle, azimuth angle and residual value of GRACE-A/B satellites. The results show that the data quality of different SLR sites is uneven, and more than 97% of the SLR observed data are very stable. There is almost no systematic error in the SLR validation of GRACE kinematic orbits, and the accuracy is better than 2.5 cm for GRACE-A and 2.7 cm for GRACE-B respectively. Under the statistics of nearly 350,000 available observations for each satellite, the accuracy indicators have strong similarity in the same site. The SLR residuals of each site obey normal distribution. The number of SLR data is inversely proportional to the observed elevation angle, and the geometric distribution of spatial observation points has a periodicity of π at different azimuth angles.