Yes, AIS can be spoofed through deliberate manipulation that broadcasts false identifying information or conceals a vessel’s true movement. This intentional act is distinct from ordinary equipment errors, poor transmission quality, or the legitimate disablement of units.
Not all ships carry AIS, and fitted units may be switched off in limited safety or security circumstances. Consequently, received data may be incomplete, unavailable, or wrong. The built-in integrity test can report equipment malfunction but does not validate the accuracy of connected sensor data; routine checks and corroboration remain necessary.
AIS target position and motion are supplied by the target's equipment, whereas radar provides own-ship measurements. The two may therefore disagree and should be cross-checked. A discrepancy is not proof of spoofing or intent. AIS does not prevent collisions by itself and does not replace visual lookout, radar plotting, use of all available means or compliance with the COLREG.
