If nobody fixed it

If nobody fixed it

What happens if the satellite clocks are left alone? A clock that runs ahead puts a time in the broadcast that is also ahead, so the phone measures the distance to that satellite about 11.5 km too short every day. On top of that, each satellite’s clock was set at a slightly different moment, so each one drifts by a different amount. Then the spheres no longer meet at a single point. On screen, after one day, the point where three spheres meet is about 19 km from where you really are.

Why?If every satellite were off by exactly the same amount, the phone could treat it as an error in its own clock and fix it. The trouble is that each satellite is off by a different amount. It’s like a test where every page is graded by a different rule: you couldn’t trust the score.

Learn more“11.5 km a day” is how much the measured distance to a satellite drifts. It doesn’t mean the dot on your map slides exactly 11.5 km sideways. How far the dot actually wanders depends on where the satellites are and when their clocks were set. The differences in when the clocks were set are just an example here.

How much distances to satellites would drift

11.5 km a day

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