“They explain and predict the orbits of artificial down to centimeters per day, or very small fractions of a millimeter per second, in the order of 0.005 mm/sec.”
I don’t doubt this is true, but how come police radar guns can only measure speed +/- a couple of MPH? Call me easily impressed, but I’m just amazed they can figure out the speed of a spaceship a bazillion miles away with that kind of accuracy.
The cops probably could do it — if NASA built them $10 million scientific-quality handmade custom radar guns that were continuously calibrated.
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.