Navigation, Seamanship, And Shiphandling (NSS) – Officer Of The Deck (OOD) Phase 2 Practice Exam

When GNSS signals are suspected of being manipulated, the priority is to preserve a trustworthy navigation solution while the situation is assessed. Rebooting or power-cycling GPS receivers can cause them to re-acquire signals that may still be spoofed, reintroducing a misleading position and time fix. That’s why the recommended action is not to restart the GPS systems. Instead, rely on other navigation sources to maintain safety: use radar to verify relative positions to known objects, gyro or flux gate for heading, the ship’s speed log for motion, and perform dead reckoning to sustain a current track. Cross-check any GPS-derived data with these independent sources, and only resume full GNSS trust after confirming the spoofing issue has been resolved through proper procedures. If applicable, report the anomaly per ship’s protocols and engage the appropriate authorities.