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parzivail / SGP.NET

C# SGP4 Satellite Prediction Library. Load satellites from TLEs, convert between coordinate systems and reference frames, observe satellites from ground stations, and more.
MIT License
33 stars 14 forks source link

Converting between reference frames #26

Open hughesjs opened 1 year ago

hughesjs commented 1 year ago

I'm writing my own library for making life easier when working with orbits.

Your readme indicates that your library can be used to convert between reference frames which is great because I need the ability to convert between J2000, SGP4 TEME, and ICRF.

However, I can't seem to work out how to do this with your library. Am I missing something here?

parzivail commented 1 year ago

Apologies for the delay. SGP.NET emits a TEME ECI from Sgp4::FindPosition, and, by extension, all ECI coordinates referenced within SGP.NET are TEME. It does not support J2000 or ICRF ECI coordinate systems, although Skyfield for Python does, which might be of some help if you want to implement the conversion equations.

When referring to reference frames in the README, I had things like ground station observations in mind. I'm sorry I couldn't be of more help, I just haven't had the motivation to implement it for my use cases.