Uploaded July 2026 | Updated September 2026, 3 weeks ago

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Something odd was going on with the signals broadcast by the GPS satellites. Steven Murdoch of University College London explains how he used statistical analysis to work out what might be going on.

To read more about Steven's findings: sjmurdoch.github.io/gps-special-messages

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This video was filmed and edited by Sean Riley.

Computerphile is a sister project to Brady Haran's Numberphile. More at bradyharanblog.com