An article linked by the article contains an informative section "How GNSS spoofing works", [1]. Excerpt:
> Effectively, if you can transmit to a GPS receiver, you can speak GPS to it and it will trust you. There's no authentication process involved, and you might even be able to MacGyver together a working spoofing device out of a hacked $15 USB-to-VGA adapter. Granted, you could easily wind up with thousands of dollars in fines or even prison time for trying it—but in strictly technical terms, there's very little stopping you.
[1] https://arstechnica.com/cars/2019/06/claims-of-tesla-hack-wi...
In reality would that happen? Probably not. There are multiple GNSS constellations these days, so just denying GPS is probably not a safe bet (you can buy civilian uBlox chips for $<50 that are tri-band...)
I love reading about the military aspect of GPS. It is really fascinating the use-cases they plan for. Hopefully they never actually are used in such an extreme scenario.
Sounds like a cat and mouse game. It only works because current spoofers are doing it sloppily. It's only a matter of time before the bad guys get their hands on this and use it to eliminate any discrepancies that the spoofers have. It doesn't sound like they found something that can't be spoofed.