Satellite Positioning and Orbit Determination System (SPODS): Introduction and Evaluation

The Satellite Positioning and Orbit Determination System (SPODS) is a software package for GNSS positioning/orbit determination, developed by the Xi’an Research Institute of Surveying and Mapping. So far it has been able to analyse GPS data and has the capability of high precision GPS positioning and orbit determination. The underlying theory and the performance evaluation are briefly addressed in this paper. The experiments are carried out with GPS data collected from about 127 IGS stations during 4~10 January 2009. The results show that the RMS 1D difference is 1.1cm between SPODS orbits and final IGS combined orbits, and that the repeatability of daily solutions of station coordinates is 1.5mm for horizontal components, and 4.5mm for vertical component, and that the consistency of ERP solutions with IGS final products is 0.025mas, 0.093 mas and 0.013ms/d respectively for pole coordinates and LOD.