I have a model that will be acting like a satellite and we need the orientation to be correct.
The problem: We are getting position data in ECI reference frame. We are also getting quaternions for orientation. We are able to show the position correctly in ECI frame with the earth rotating and position changing and the sun staying relatively still. It is with the orientation where things get strange. I created a sandcastle below for reference. There are three comments in the test sections. to test each section uncomment the code snippet.
Sandcastle: Orientation