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Understanding AIS & GNSS Spoofing

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Written by Vasilis Kontas
Updated this week

🔍 What is Spoofing?

Spoofing involves transmitting false data to misrepresent a vessel’s identity or location. There are two main types, each with distinct origins and implications:

• GNSS Spoofing

GNSS (Global Navigation Satellite System) spoofing is typically caused by external actors, such as military or state-level entities. These actors emit counterfeit GPS-like signals to deceive a ship’s onboard navigation systems. It can confuse both the vessel and external tracking systems, placing the vessel in an incorrect position.

GNSS spoofing is commonly seen in wartime zones, military exercises, or geopolitical hotspots, and may affect multiple vessels simultaneously.

• AIS Spoofing

AIS (Automatic Identification System) spoofing is usually conducted by the vessel itself or its operator. It involves intentionally transmitting falsified AIS messages, such as:

  • Fake GPS coordinates

  • Falsified vessel identity (MMSI, name, call sign)

  • Duplicate transmissions to simulate “ghost” ships or mislead tracking systems

This is typically done to hide real movements and evade detection.


⚠️ Why It Happens

GNSS Spoofing

  • Used by military or government entities to disrupt maritime awareness during conflicts or to protect sensitive assets

  • Common in areas under military occupation, airspace defense zones, or regions near active hostilities

  • Affects multiple ships at once, regardless of intent

AIS Spoofing

  • Used to intentionally disguise vessel activity, often to conceal:

    • Sanctions evasion

    • Illegal ship-to-ship (STS) transfers

    • IUU fishing

    • Smuggling and trafficking

Hot zones include: Strait of Hormuz, Black Sea, Gulf of Oman, South China Sea, Eastern Mediterranean


👀 What You Might See on MarineTraffic

Spoofing often shows up as anomalies on the map, such as:

  • Vessels “jumping” across oceans

  • Duplicate vessels with identical names or MMSIs in distant areas

  • Ships anchored at sea with no port calls for long durations

  • Unrealistic voyage durations between ports

Interference pattern of GNSS jamming in the Red Sea Port Sudan area in May 2025 - MarineTraffic.

Stationary circular pattern example - MarineTraffic.

Erratic loitering example - MarineTraffic.

A fabricated vessel trajectory that lasted for a period of 5 months - MarineTraffic.

PIONEER (now SPUTNIK ENERGY) spoofing her position back in July 2024 - MarineTraffic.


🛠️ How MarineTraffic Detects and Manages Spoofing

MarineTraffic applies both automated and human intelligence to flag suspicious activity:

  • Anomaly detection (e.g. position jumps, unnatural speeds)

  • Cross-checks with satellite imagery and known vessel behaviour

  • Behavioral models to spot spoofing patterns

  • Manual investigations by our Risk & Compliance team

🟡 Spoofed signals are still shown on the map, as they offer valuable intelligence. They are flagged internally and excluded from analytics and reporting when confirmed.


🌟 Risk & Compliance Intelligence Now Available

MarineTraffic now offers access to a new Risk & Compliance service, designed for customers who need more than just vessel tracking:

  • Sanction Risk Detection: Identifies vessels tied to sanction lists or PSC bans

  • Management Risk Assessment: Screens ownership and operating entities

  • Operational Risk Monitoring: Highlights suspicious or deceptive patterns

  • Flag Risk Analysis (coming soon): Measures risk by flag state profile

  • Compliance Tab: A 360° vessel risk profile, visible on the Vessel Details page

  • Color-Coded Risk Indicators: Instantly assess risk (Red: Sanctioned, Yellow: Risky, Green: Clear)

  • Global Coverage: Extends across IMO-registered vessels with new types being added

📩 Speak with your CSM to learn more or request a demo.


✅ What You Can Do

  • Use the “Report an Issue” form to flag suspicious activity

  • Contact our team for tailored analysis or support available for our Risk & Compliance customers


🚧 Coming Soon

We’re building new tools for greater control over spoofed data:

  • “Clean Tracks” Toggle – Filter out spoofed AIS positions on demand

  • Regional Spoofing Heatmaps – Visualize spoofing risks by zone

  • Spoofing Alerts – Get notified of risky behavior across your fleet


For further help, contact your account manager or support team. Your awareness is key in navigating today’s complex maritime data environment.

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