Ibra wrote:
If someone is able to jam GPS on large scale, I don’t see what will prevent them from doing the same with a VOR/ILS/DME?
Physics.
The GPS signal is at best -125dBm, which is around 3.2 × 10E-16 (0.32 Femtowatt, 0.00032 Picowatt). This is what is left over after travelling all the way down from the 20,000 km orbit, where it is transmitted with around 50W (times antenna gain)
Any jamming signal on earth or carried by a small drone a few miles up is much, much, stronger. Now, GPS jamming is not quite as easy as blaring in the GPS spectrum, but it should be pretty obvious that it does not require much power to cover a large area.
Also, geometry. To generate a signal at the receiver that is much stronger than the one you want to jam, it helps if you are closer to receiver than the transmitter. For a GPS, that basically means “being on Earth, with line of sight to the aircraft”, while for the ILS/VOR it means “being close to the aircraft”
The ILS and VOR signals are much stronger and more local. While the receivers are of course a lot less sensitive and work in a completely different way, and jamming is actually easier if you have the power, widespread jamming is next to implossible, and would require many, many transmitters (or a HUGE one high up)
There is a real difference between gps being completly off versus wrong but sensible reading, as pilot who relies on GPS, I am more scared of the later and I prefer to see a red flag
For widspread jamming of GPS, you will probably need a full constellation up in the sky while for radio/radar stuff well: good luck, the technology is quit proven and people try to hack it in cold war without much sucess due to simple physics you mentioned (you need a lot of signal grid & power to cover space/time and all wavelengths, such infrastructure will not go unoticed and for sure you can’t fit it in a truck)
Military technology is capable of jamming GPS so it displaces your position and everything looks ok.
I don’t know if they can bend the WAAS signal as well however.
All the civilian jammers just jam the signal and the jamming is obvious.
Airliners are not affected because most have INS which use DME/DME for position updates (as well as GPS, but only in the most modern airliners).
