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Robert McNees /
npub188w…3emc
2024-06-24 14:24:21
in reply to nevent1q…yw2y

Robert McNees on Nostr: Calculating the fractional frequency shift of the satellite clock compared to the ...

Calculating the fractional frequency shift of the satellite clock compared to the ground clock is a homework problem in GR textbooks.

Orbiting at 4.2 Earth radii, SR slows it down by ~ 250 parts in 10¹². The GR effect speeds it up by ~ 697 parts in 10¹².

General relativity produces the larger effect, and the orbiting clocks runs ahead of the earthbound clock by around 446 parts in 10¹². That’s an extra 38,500 nanoseconds per day.

This is a lot for GPS, which requires really precise timing.
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