ChrisRowland wrote:I can understand jamming, the signal is very weak, but spoofing? The receiver is getting data from multiple satellites and all of them would need to be replicated by the spoof signal - woudn't they? I've seen it done on NCIS but that's not reality.
I'm not denying what you are saying but a little surprised. Could you really do this for a random passing aircraft or do you need to be really close so that you can be confident that all the signals come from the spoofer?
To do it to any random passing aircraft you would need transmitter powerful enough to be stronger than GPS signal (not that much power is actually needed as you would be significantly closer) or directional antenna and point it at the aircraft.
All you need is https://www.amazon.co.uk/Great-Scott-Ga ... 01COVX464/
and a PC - this will cover ~200-300m (assuming line of sight).
Then if you want better range a 2nd hand RF power amplifier will run you into few 100's + decent antenna (pretty cheap).
Both images below were taken ~10 minutes apart (time it took me to find my old sat nav as additional device to test against). 1st one shows somewhere in scotland, 2nd one somewhere in china.
I have also tested it against IFR GPS, which to make it worse, was perfectly happy to go into approach mode and provide LNAV approach (and with some work SBAS signals can also be simulated so LPV should also be possible)