Given that the Russians took down all of Ukraine's telecoms only to realize that that meant that they couldn't communicate either, and had to therefore use insecure systems does make me think that perhaps they haven't thought it through.
@echodot@IrateAnteater I suspect, despite occasional advances, that on the whole they have thought little of it through. And now their, or rather putines, pride won't let them just say "sorry. We fecked up, just let us back out"
civilian GPS operates at a few fixed frequencies like 1575.42 MHz, 1227.60 MHz, and L5 at 1176.45 MHz (plus 2-3 more; military GPS is a different story). The structure of the GPS data is also fairly well known; all of this is easy to find on the goog.
So you hop on the same frequency start spamming bad GPS data. wrong time stamps, wrong satellite info, etc. with a little effort you can convince a long range missile they're off by 2 miles and should veer left hard.
or you just put a shit ton of noise on the same frequencies and make it so it's forced to use inertial navigation (which isn't very accurate).
GPS is a product of the US military; its usefulness to them would be limited if it were North America only, since they mostly wanted it to tell where they were, wherever they happened to be in the world that they had no knowledge of but were actively fuckin' with.
GPS is equally available to civilians in Freedomland as it is to civilians wherever else in the globe. They used to arbitrarily fuck up the signal resolution for the non-military version, until they realized that all they were doing was (a) mildly inconveniencing tech companies who had go through the rite of passage of assigning a single junior programmer to determine how to mostly undo their resolution-fucking-with which wasn't that challenging (b) motivating every other country to develop their own GPS equivalents.
By the time they just let everyone have real GPS, people had cottoned on to the idea that maybe putting your navigation under the whims of the US military wasn't a great idea, and had gone to the pretty significant expense of developing their own. So now there's a bunch of them, and you can pretty much choose whichever one pleases you. But with the exception of NavIC, they're all available all over the world.