See my reply to LeoPanthera.  Shiva2012 doesn&#x27;t claim that GR effects can&#x27;t be detected using GPS satellites, he&#x27;s saying they are already corrected in a way that doesn&#x27;t require understanding GR at all: by regularly re-syncing the clock with ground.  In a hypothetical world without GR, this would be a mysterious drift rather than a non-mysterious one, but it wouldn&#x27;t make GPS any less possible.<p>Do you have a link from any of those prestigious places that says GR is actually necessary for making GPS work?