I’m not sure if this forum is the right place for this kind of question, or if I should try my luck on Stack Exchange-type sites.
I have a set of TDM measurements of Starlink satellites. These TDMs contain right ascension, declination, time (and the latitude, longitude, and altitude above sea level of the observer). I want to compare them with SpaceX’s publicly published flight plans, which I believe are in the MEME2000 frame. Ideally, I would like to transform the SpaceX MEME data to RA/Dec as seen from the observer’s location. However, every approach I’ve tried so far has resulted in vastly different (and incorrect) results.
I know this problem is related to my confusion regarding different reference frames and is not strictly Orekit-dependent, but I would appreciate any help, advice, or even code snippets on how to handle this issue.
I would suggest first to plot RA/DEC with both your data and published data.
On a graphical plot, one can sometimes see if for example there is a pattern in the difference. If plots seems simply offset in right ascension, it would point to a date problem. If plots are both offset and stretched in right ascension, it would point to an inertial frame vs. Earth frame confusion. If plots seem scaled, it could point to a missing radians/degree conversion.
As another debugging source, using the TLE for the satellite (if you know which one it is) from SpaceTrak would possibly be useful - there’s a few good tools for quickly converting between a TLE and Ra/Dec for an observer to help you eyeball any issues, Skyfield is my personal go-to but there are many others. I’ve also tripped up on time zones before. Where are you getting the flight plan data from?