Incidentally, there has been a recent escalation in this: over Iraq commercial airline pilots have been reporting increasingly successful GPS spoofing, with GPS positions being shifted by tens or hundreds of nm, the clock being shifted, etc. In some cases this has exposed bugs in aircraft software where it has not successfully recovered the GPS position even after leaving the affected area, leaving them with degraded navigation all the way to the destination.
This is not as dire as it might sound, as there are plenty of other ways for an aircraft to determine its position, though it certainly reduces the margins for error in some cases. But it’s interesting because such spoofing should be extremely difficult to carry out successfully, especially on a moving target like an airliner.
Current areas where jamming is being detecting.
* https://gpsjam.org