Long arc orbit determination for Mariner 9 using combined radio and optical data types

Results of postflight orbit determination for the Mariner 9 trajectory (Mariner-Mars 1971 mission) using Doppler data combined with optical data in the form of TV photographs of the natural satellites and Mars' surface features. It is shown that the combined data yield a solution which is a factor of 3 to 5 better than that obtained from Doppler-only solutions for the node of the orbit relative to the plane perpendicular to the Earth-Mars line. Consequently, these optical data types have a demonstrated potential to significantly improve planetary orbiter navigation accuracies.