QUASAR paper reports hybrid quantum classifier for satellite signal authentication

Researchers describe QUASAR, a quantum-classical neural-network architecture for physical-layer authentication of X-band synthetic-aperture-radar satellite signals. The system combines a CNN spectrogram encoder with a variational quantum circuit to distinguish hardware signal characteristics. In tests against replay, crafted-IQ injection and space-borne spoofing, the paper reports rejecting spoofed transmissions in 89.7%, 94.1% and 81.3% of attempts, respectively. The authors also report that it matched classical-baseline accuracy with 10% of their training data.