As I recall from my childhood (pre-prequel days), 5 years passed between A New Hope and Empire Strikes back, then another 5 years passed before Return of the Jedi. In those years, Luke went back to Dagobah to finish his Jedi training, Lando got an undercover job working at Jabba's palace, and and Leia/Chewbacca tracked down Boush and murdered him, just so they could have his outfit.
The freaky thing about GPS is that those accurate timers in those satellites are not on our 24-hour cycle. Earth's gravity affects the satellites less than it does down here on Earth (duh), and that speeds up the passage of time. The timers have to run a little bit slow to make up for the difference caused by low gravity.
Sounds like they work for the Redundancy Department of Redundancies.
(Edited after seeing the sarco device.)