Too late to edit, but here is the paper that I meant: https://apps.dtic.mil/sti/pdfs/ADA516975.pdf https://apps.dtic.mil/sti/pdfs/ADA516975.pdf. At a mere 12 pa

Too late to edit, but here is the paper that I meant: https://apps.dtic.mil/sti/pdfs/ADA516975.pdf https://apps.dtic.mil/sti/pdfs/ADA516975.pdf. At a mere 12 pages it's an easy read. Needless to say, the military is almost certainly the highest quality source for info on the actual engineering practicalities of GPS. First sentence of the introduction: The Operational Control System (OCS) of the Global Positioning System (GPS) does not include the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require