> Purportedly newer GPS satellites don't have the option anymore.
That does sound suspiciously like something the military would want you to believe
Re:China's GPS 'rival' Beidou
by vlovich123 on Tuesday October 23, 2018 @03:49AM
(#18281515)
Selective availability was defeated a very long time ago so no reasons to doubt that the military gave up on it. Pretty sure they're just using an encrypted transport for the military signal so they can do whatever they want to civilian GPS wholesale without impacting the military. However, I'm not sure how that will work since it underpins our entire economy from logistics to air travel. On the other hand, at the point the military is disabling civilian GPS probably the economic impact is less of a concern.
Re:China's GPS 'rival' Beidou
by labcomputer on Tuesday October 23, 2018 @11:22AM
(#18284132)
It's worth mentioning here that SA-less Block IIF (and newer) satellites came after "codeless" and "semi-codeless" techniques were publicly-known. Those allow a receiver to use the encrypted P(Y) code to obtain a precise position fix without any knowledge of the encryption key.
There are probably other, newer ways to prevent an adversary to use the GPS signal, but there is little reason to doubt that SA is gone.
They also had the option in older satellites of turning on selective availability, which would degrade the civilian location service from 5-meter to 100-meter accuracy without affecting the military service. Purportedly newer GPS satellites don't have the option anymore.
https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_...