Precision Orbit Determination at the Yunnan Observatory

This paper first reviews the fundamentals of the Precision Orbit Determination (POD),and subsequently describes the details of the POD at the Yunnan Observatory (POREDY).These details include the processing steps,adopted dynamic models, and reference systems.We further list the residual analysis to eliminate "wild values" and analyze the data quality of each station in the satellite-tracking network.Using the POREDY software, we analyze the global SLR data of the satellite LAGEOS I between Jan 1,2004 and Oct 26,2004,and the global SLR data of the satellite AJISAI between May 3,2008 and Feb 26,2009.The data consist of those of orbital arcs with 3-day spans.The total RMS of the POREDY for an arc of LAGEOS I is typically 1.5 cm,and is always less than 3 cm.The total RMS for an arc of AJISAI is typically 3.5 cm, and is always less than 6 cm.The results are similar to those from the CSR,which indicates the reliability of the POREDY software.