GPS satellites tell us where we are, which is all understandable and easy to explain given all the signals and maths that allow us to see ourselves as small dots on a map. While they can’t tell you where you left your car keys (yet), millions of people rely on them for directions, locations, and avoiding traffic. But how can GPS satellites keep track of their own position in order to relay the proper location to our devices if they are constantly orbiting the Earth? What informs them of their location?
This is an important question since, for GPS to work, and for us to know where the satellites are, we have to know the exact orientation of the Earth. While this may appear to be a simple task, it is not. In this video by the English YouTuber and educator Tom Scott, you’ll visit the NERC’s Space Geodesy Facility, tucked away in the English countryside. This facility shoots lasers at satellites because it turns out that pinpointing a satellite’s position exactly is quite difficult. If you’re curious to learn how and why, make sure you check out the video embedded above, and as always, enjoy.