It'd be more practical to have a faraday cage and several GPS transmitters to spoof a location (let's say 33.783, -118.14899); turn on the device, if it tells you it's located at 33.783, -118.14899, then it's GPS receiver is working correctly, anywhere else, then there's something wrong...
Reminds me of an anecdote that getting a rideshare in Moscow is difficult nowadays, because GPS for the whole city is jammed and the driver won't be able to find you.
Is it easier to spoof GPS transmissions such that the phone will calculate it's at a specific coordinate? Rather than just check where they are reporting?
If they're worried about someone guiding missiles with satnav, they are probably jamming those both plus the European one, would be my guess, or since they control their own GLONASS system they could be encrypting it if it supports that, or shutting it down in those areas.
Reminds me of an anecdote that getting a rideshare in Moscow is difficult nowadays, because GPS for the whole city is jammed and the driver won't be able to find you.