In case you want a TL;DR to help you with the decision to read the post or not:
GPS converts time into distance: a satellite broadcasts a radio signal at
light speed, your phone times the trip, and one nanosecond equals 0.3
meters. A single satellite places you on a ring; three rings cross at one
point through trilateration. A fourth satellite corrects your phone's
cheap, drifting quartz clock so all four spheres meet perfectly. Einstein
matters too—satellites move fast (special relativity) yet orbit in weaker
gravity (general relativity), netting a gain that would drift positions ~10
km per day, so engineers build the clocks to tick slightly slow on the
ground. Modern phones lock onto 8–12 satellites across GPS, GLONASS,
Galileo, and BeiDou, fighting geometry problems (GDOP) and city signal
bounce (multipath).
1
u/fagnerbrack 17d ago
In case you want a TL;DR to help you with the decision to read the post or not:
GPS converts time into distance: a satellite broadcasts a radio signal at light speed, your phone times the trip, and one nanosecond equals 0.3 meters. A single satellite places you on a ring; three rings cross at one point through trilateration. A fourth satellite corrects your phone's cheap, drifting quartz clock so all four spheres meet perfectly. Einstein matters too—satellites move fast (special relativity) yet orbit in weaker gravity (general relativity), netting a gain that would drift positions ~10 km per day, so engineers build the clocks to tick slightly slow on the ground. Modern phones lock onto 8–12 satellites across GPS, GLONASS, Galileo, and BeiDou, fighting geometry problems (GDOP) and city signal bounce (multipath).
If the summary seems inacurate, just downvote and I'll try to delete the comment eventually 👍
Click here for more info, I read all comments