this post was submitted on 23 Nov 2023
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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.
Pretty much this, look up Kalman filters if you want details. The most likely explanation is that they are tuned to effectively trust GPS more than the internal IMU for long periods of time. Really good IMUs are very expensive and still drift but have high speed output. When it works well, GPS is cheap and doesn't drift but with a slow update rate. The cost optimisation probably means that the IMU data is usually only trusted for a few seconds, probably 10 min at most before it takes whatever the GPS says as truth. If they lost gps signal through jamming, then they would keep navigation on the less certain IMU data, but the GPS sensor thinks all is well so they shift position.
There is probably a software upgrade to the filter that could be used to limit these attacks, but I imagine it's an active area or research.