I'm relatively new at GPS positioning, and have come across precise orbital calculation files here. I've parsed the sp3 files and gotten the values into something I can work with, but I don't know much about the coordinate systems used. Is there a simple way to convert from the IGb08 or IGS14 system to the ECEF system that GPS uses? I'm working in Python, and any libraries or code would make life easier.
I've looked at the ITRF website, but don't know what SINEX files are, or what they're talking about, really.