Europe’s aviation safety body is working with the airline industry to counter a danger posed by interference with GPS signals - now seen as a growing threat to the safety of air travel.
Interference with global navigation systems can take one of two forms: jamming requires nothing more than transmitting a radio signal strong enough to drown out those from GPS satellites, while spoofing is more insidious and involves transmitting fake signals that fool the receiver into calculating its position incorrectly.
According to EASA, jamming and spoofing incidents have increasingly threatened the integrity of location services across Eastern Europe and the Middle East in recent years.
Yes, and those messages can be signed to allow receivers to verify they are a credible source of position information.
Not sure what the above commenter meant with the last sentence though. My understanding is that GPS satellites don’t just relay signals, but instead have computers on board to calculate the appropriate signal all the time. So I assume a software update is required.