The claim that coordinate transformations are required in orbit propagation to relate different reference frames is a fundamental trigonometric and mechanical truism in astrodynamics and celestial mechanics, requiring no external citations.
The claim is a foundational definition regarding how reference frames (e.g., inertial versus orbital or body-fixed) relate during space navigation and orbit calculations. As a basic geometrical and physical truism, it falls under common knowledge. No retrieved papers specifically test or evaluate this exact general axiom as a novel hypothesis, making citations unnecessary.