Orbital Coordinate Systems, Part I By Dr. T.S. Kelso By this
point, I hope to have helped you develop an understanding of two
key aspects of practical orbital mechanics. The first has to do
with why we use the orbital models we do for predicting the
position of earth-orbiting artificial satellites. As with any
computer model, orbital models must trade off accuracy for
computational speed. Which model you decide to use will depend
upon which of these factors is most important to you. Of course,
from a practical perspective, the choice of orbital model is
also strongly influenced by the availability of data (element
sets). Knowing that orbital element sets are generated by
fitting observations to a trajectory based upon a particular
orbital model is the second of our key aspects. Accuracy of our
predictions will depend upon using that same orbital model. Up
to now, however, all we've really talked about are orbital
element sets. But how do we get from the data in these orbital
element sets to something we can u