GNSS Spoofing Detection

Techniques that identify counterfeit GNSS signals, where a transmitter feeds a receiver false ranging data to drag its computed position or time off true. Detection methods include monitoring received signal power and automatic-gain-control behavior, checking cross-constellation consistency across GPS, Galileo, GLONASS, and BeiDou, cross-checking against an inertial navigation system, and verifying cryptographic authentication such as Galileo’s OSNMA. Incidents near the Strait of Hormuz and the Black Sea since 2019 have shown ships positions jumping ashore. IMO MSC.1/Circ.1644 (2024) gives guidance on detecting and mitigating GNSS jamming and spoofing.