Invisible systems
GPS
Signals from space help a receiver work out where it is.
GPS satellites broadcast timing and orbital information. A receiver uses signals from multiple satellites to calculate position and time.
A closer look
The picture, in three parts.
Broadcast
Satellites transmit signals.
Measure
A receiver compares the arriving signals.
Calculate
Measurements support a position and time solution.
Where could this take you next?
Sources & further reading +
Short explanations, grounded in published sources. Follow the originals for depth and context.
Sources checked: 10 September 2026. Visuals are illustrations, not documentary evidence.
Our approach to sources and corrections