Police radar cost about $1000, are hand held and have observation intervals of a couple seconds and produce reasonable real-time estimates. They are subject other sources of error, included unmodeled target accelerations and effects due to the target motion not being aligned with the radar line of sight.
Satellite orbits are developed using many thousands of independent observations by multimillion dollar sensors positioned all over the globe, processed off line using large computers and sophisticated algorithms. They really are not comparable.
“Satellite orbits are developed using many thousands of independent observations by multimillion dollar sensors positioned all over the globe, processed off line using large computers and sophisticated algorithms.”
So I infer it is triangulation to the Nth degree that permits such precision?
Memo to Self: do not let Barack Obama know about this capability, else he will direct GPS satellites to catch speeders all across America and use the revenue from fines to help bankroll the growing welfare state.