Risk Intelligence

AIS gap / dark period

An AIS gap, or dark period, is an interval in which the vessel record has no qualifying position report. The platform opens a dark event once a vessel's position gap reaches or exceeds 6 hours — one global cutoff, applied the same way everywhere, not a coastal-vs-open-ocean split. Once a gap is open, a separate step that classifies its likely cause also checks a shorter 2-hour bar, gated on whether the platform has any active transfer hotspot on record at all rather than this gap's actual distance to one, and it only runs after the 6-hour cutoff has already been met — so it never changes which gaps get flagged. Overwatch records gap start, gap end when available, duration, last known position, and reappearance context, then uses the event as an input to risk scoring and review. A gap is evidence that the AIS record is incomplete; it is not proof that a transmitter was deliberately disabled, that the vessel was absent, or that cargo was transferred. Additional evidence is required to interpret cause or intent. Why it matters for grain flows: a gap marks a break in voyage evidence that can qualify route and cargo inferences without turning missing data into a fact.

Read the AIS gap risk-factor methodology for validation context.

See how this fits into the platform: Axiom Overwatch · pricing