Maybe new to ADS-B, but a long-established technique in other fields.
I know of ham radios from 15 years ago which could fingerprint incoming signals to identify (and block) "IQ-zero" operators. It involved looking at signal rise rate, deviation variations, frequency difference (ie PLL offset), ... Just didn't involve "AI" back then, so obviously this new research is completely different.
Biting the hand that feeds IT
