As a spacecraft travels through space and moves farther from Earth, effects of differing reference frames and radio propagation time become progressively more important. This article studies the relationship between observations and signals on Earth and on a distant spacecraft, including the effects of relativity. By better understanding the complex transformations between these frames of reference, researchers can acquire more precise measurements and better track the motions of bodies in the solar system.

http://www.raa-journal.org/raa/index.php/raa/article/view/1022