GPS has a special mode for theater-wide military operations that is much harder to jam.

https://www.lockheedmartin.com/en-us/news/features/2025/regi...

You could still jam this but you need to overcome 20+dB of additional gain in the transmission. If the party you are jamming has anti-radiation missiles, you are forced to make yourself an extremely hot and unambiguous target to participate in jamming at these power levels.