Precise orbit determination for geostationary satellites with multiple tracking techniques

A new precise orbit determination (POD) strategy based on the combination of satellite laser ranging (SLR) and C-band transfer ranging for geostationary satellites (GEO) is presented. Two approaches to calibrate ranging biases of the C-band ranging system are proposed, namely the two tracking system co-location comparison and the combined POD method, with calibration accuracies estimated to be 0.5 ns and 1 ns respectively. Using data from a C-band tracking network in China, POD experiments indicate that meter-level POD accuracy is achievable for GEO. Root-mean-square (RMS) of the post-fit C-band ranging data is about 0.205 m. The radial component errors of POD are evaluated with SLR data from a station in Beijing, with residual RMS of 0.133 m. Orbital overlapping experiments show the total orbit error is a few meters. Computations of SLR residuals also suggest that for 2-hour prediction, the predicted radial error is about 0.373 m.