Wow, what a masterpiece of an article with numerous great visualizations! I learned a lot!
Be sure to check out his archives. He has a lot of articles with amazing interactive visualizations.
I’m glad I read your reply, I was planning on skipping the article because I assumed I basically knew how GPS worked. Not only is it beautifully presented, it builds up each step very carefully and pointed me at quite a few bits of the problem that I’d skipped in my mental model (why the orbits were chosen and how the time synchronisation works, for example). Even the bits that I did know well, I thoroughly enjoyed reading the description and playing with the animations.
I’m going to keep this as my gold standard reference for how to do scientific communication.
I still find it amazing that this was launched at a time where there was still sufficient uncertainty about relativity that they built the system to operate in Einstein-was-right and Einstein-was-wrong modes, just in case they accidentally disproved his theories (as I recall, the first GPS satellites were the first clocks put into orbit that were sufficiently sensitive to measure relativistic effects). The fact that I can now buy a cheap consumer device that can receive signals from four such systems and tell me my precise location anywhere in the world is a phenomenal achievement. The fact that four such systems need to exist because four large political entities don’t trust the other three is much less of an achievement for the species.
GPS is just so well-designed, you put it well.
wow. I can’t imagine how much work went into this. it’s like an interactive textbook!