@michaelcoyote @osinttechnical GPS was built for ICBM navigation; one of the great Cold War unintentional innovations.
Thirty years after initial full operational capability, the intended-to-be-enabled smite button has been downscaled and widely deployed.
@necedema @michaelcoyote @osinttechnical SLBM and (at the time, planned) mobile ICBM launchers benefit greatly from knowing just where they are on launch, and that was the original justification for the stonking price tag of the GPS constellation.
Then it became the world's clock and a US national technical asset, but in the beginning, it was so the missiles would know where they were on launch.
(Also, jamming GPS at the peak of a strategic ballistic missile's trajectory is non-trivial.)