Commercial Flights Are Experiencing ‘Unthinkable’ GPS Attacks and Nobody Knows What to Do::New “spoofing” attacks resulting in total navigation failure have been occurring above the Middle East for months, which is “highly significant” for airline safety.
But the article mentioned that “the spoofing corrupts the Inertial Reference System”. How?
Yeah I have the same question. Based upon a comment above, it looks like the independent gyro system is updated for drift based upon the spoofed GPS data and thus causes issues. If the IRS is not updated at all then drift becomes a bigger issue but if it’s updated regularly with valid GPS data then it’s a good thing. So the challenge is to only update the gyro drift with valid GPS data which I am guessing is hard to determine.
If it’s a smaller plane (such as a CRJ / ERJ) with only one IRU, it will not be able to determine if GPS is valid or not, so the drift correction gets spoiled.
Large commercial aircraft are using 3 IRUs, with newer aircraft using ADIRUs. If GPS does not agree with the three IRUs, the GPS data is thrown out. If the GPS is within tolerance, correction is applied. You could build up very small errors over a long distance, but you should still be pretty close to the airfield when you get there.