Emergency Contact Jamming and Spoofing - Responding to GNSS and AIS Interference Home Latest updates News Jamming and Spoofing - Responding to GNSS and AIS Interference 7 Aug 2025 Download article PDF Sign up for alerts Safe navigation of vessels today primarily relies upon Global Navigation Satellite Systems (GNSS) and Automatic Identification Systems (AIS) for real-time positioning and situational awareness. However, both systems operate using radio frequencies – which makes them susceptible to interference.  With ever-increasing political instability across the globe, the frequency and volume of deliberate and targeted disturbance, primarily via jamming and spoofing, is becoming increasingly common – posing significant risk to the safety of shipping.  Below is a short guide, jointly prepared by the United Kingdom Hydrographic Office (UKHO) and The Shipowners’ Club, exploring the difference between jamming and spoofing, with practical steps crews can take to prepare for and respond to these threats. Jamming vs spoofing: what’s the difference? Deliberate interference with GNSS and AIS navigational systems typically falls into two categories: jamming or spoofing. Jamming : Using a device to deliberately interfere with radio signals, blocking the system’s ability to receive accurate data. Spoofing : Sending fake radio signals to deceive a navigational system into showing false positions or data.                                                         Image 1: AIS spoofing of vessels at sea                                                        Image 2: AIS spoofing of vessels on land Image 1 shows vessel AIS positions being spoofed to appear to circle an offshore platform, in image