GPS
Core route · invisible systems
Timing error, trilateration, and orbital geometry in one mental model.
GPS feels like magic until you can see the timing problem underneath it. This note connects satellites, clock bias, line-of-sight geometry, and signal travel time so the system reads like engineering instead of mystery.
At a glance
The maintained version lives at the route linked here, with this garden note keeping the embed and editorial framing.
Positioning systems usually get reduced to a map dot. This shows the hidden timing and geometry that make the map dot possible.
Start with trilateration, then add clock bias and satellite motion. The big jump happens when you see how a tiny timing error turns into a large positioning error.
About 12 to 18 minutes. Intermediate. Best if you want one invisible system made concrete through timing and geometry.
Embed
Reading path
- Open the live interactive: https://kohnnn.github.io/interactive-explanation/gps/
- Continue through Visual Notes for more geometry and systems explainers
- Pair it with Mechanical-Watch if you want another precision-timing system from a completely different domain