A goal of GPS triangulation is to sync a local device's clock to TAI/UTC, but it is still a sync done with 3 to 5 (or sometimes more) satellites and math that i

A goal of GPS triangulation is to sync a local device's clock to TAI/UTC, but it is still a sync done with 3 to 5 (or sometimes more) satellites and math that isn't just Euclidean triangulation but needs to account for relativistic effects. At the scale of GPS and the relative velocity differences between a moving cellphone and moving satellites in orbit that is mostly just accounting for drifts on the order of microseconds, but GPS triangulation does need to account for those and does the relativistic math (on a device, in your hand!). It's an incredible mathematical achievement that the byproduct of triangulation of your position on Earth also syncs your clock extremely close to our best and strictest clocks. Some of that math is relativistic. Certainly not on the scale (velocity/time/distance) that most people think of when they hear relativistic but partly because something as incredible as GPS satellites orbiting in space is no longer science fiction but a mundane part of our day to day lives and devices. There are satellites broadcasting clock signals from space 24/7! With relativistic math our phones figure out where we are down to foot, nearly (sometimes more) and figure out a precise time for where we are! It's incredible and it is a wonderful thing to take advantage of. Relativistic time math happens every day now (sometimes a lot of times in a day) in our lives, and we don't need to think about it.