1 min
Explainer

How GPS works: satellites, clocks and distance

8 min original · Original explainer · Technology

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A GPS receiver does not send a signal to find you. It listens to timing signals from several satellites and calculates its distance from each one. This explainer covers the role of precise clocks, why at least four satellites are needed, and what can reduce accuracy.

Summary of a 8 min original

Key takeaways

  • Distance comes from how long a signal takes to arrive
  • Four satellites are needed to fix position and receiver time
  • Atmosphere, buildings, and reflections can reduce accuracy
Watch 1 min summary

Chapters

  1. Signals and time
  2. Measuring distance
  3. Why four satellites
  4. What limits accuracy

Sources

Original from: Original explainer
Photo: NASA's Scientific Visualization Studio - Science and Technology Corporation/Kel Elkins, Public domain, via Wikimedia Commons

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