A vessel goes dark. Its AIS transponder stops transmitting, or it keeps transmitting — but from the wrong place. The first scenario is a dark period. The second is spoofing. Both are investigatively significant. Both are also frequently innocent. The discipline required to tell the difference is what separates a defensible finding from a speculative one. AIS gaps are among the most commonly misread signals in maritime OSINT, and that misreading has a consistent pattern: the gap is treated as the finding rather than the trigger for further analysis.
Apply dark vessel analysis when an AIS gap in open water requires classification, when a speed or position anomaly may indicate spoofing, or when an investigation requires documented evidence of intentional transponder deactivation. A transponder silent for four hours near a known relay gap is not the same as one silent for the same period in a known STS transfer zone. Each indicator, taken individually, is ambiguous. The pattern, corroborated across platforms and data sources, is not.
MAR-003 sets out the methodology for classifying AIS gaps, testing spoofing indicators, and documenting dark vessel findings to evidentiary standard.
Six tooling sources, five OPSEC requirements, eight workflow steps, five false-positive patterns, six chain-of-custody requirements, six key queries.
|
01
Required Tools
Six platforms covering AIS, SAR imagery, VIIRS, and spoofing detection.
|
02
OPSEC
Satellite query attribution and dark period premature disclosure risks.
|
|
03
Workflow
Eight-step sequence from baseline track to spoofing classification.
|
04
False Positives
Five receiver and platform artefacts misread as intentional spoofing.
|
|
05
Chain of Custody
Six requirements for documenting dark periods and satellite corroboration.
|
06
Key Queries
Six queries across AIS platforms, SAR, and VIIRS nighttime data.
|
Download the card.
A PDF version of MAR-003 is available below for Signal subscribers.
This reference card is for Signal subscribers.
Signal subscribers get the full OSINT Reference Card library, plus every Methods tutorial and Forensic Dossier.
A Signal subscription gives you:
• Full OSINT Reference Card library
• Methods, all tradecraft tutorials in full
• Shadow Analysis, all evidence-based reporting
• Forensic Dossiers, full access
• Discord access included
