What GPS spoofing means at sea
Ships use Global Navigation Satellite Systems, or GNSS, to calculate position, speed and precise time. GPS is the best-known constellation, but modern receivers may also use Galileo, GLONASS and BeiDou. The signals travel from satellites roughly 20,000 kilometres above Earth, so they are extremely weak by the time they reach a vessel. A stronger local transmission can overwhelm or imitate them.
Jamming blocks or degrades the signal, leaving the receiver without a dependable position. Spoofing is more deceptive: a transmitter imitates genuine satellite signals and persuades the receiver that the ship is somewhere else. In 2025 the IMO, the International Telecommunication Union and the International Civil Aviation Organization expressed grave concern about the increase in both forms of interference.
A wrong dot does not mean a wrong voyage
When GNSS is spoofed, the ship's onboard receiver may calculate a false position. AIS can then broadcast that position to shore stations and satellites. The map is faithfully displaying bad source data. The vessel may still be following its planned course using radar, visual bearings, gyrocompass data and other independent navigation methods.
Why the problem became impossible to ignore
GNSS interference was once treated as an occasional technical anomaly. It is now a routine operational risk around the Baltic Sea, Black Sea, Red Sea and Arabian Gulf. The French Navy's MICA Center identified those four areas as the global hotspots in its 2025 maritime security report, with an average of around 400 ships affected each month.
The 2026 Middle East conflict pushed the scale much higher. Maritime intelligence company Windward recorded nearly one million instances of satellite-positioning interference in the region from 28 February to May, according to reporting by Le Monde. Almost 1,100 ships were affected on the first day alone. Some vessel icons appeared on land, beside airports or at locations far from the ships' physical tracks.
The safety consequences are no longer theoretical. The Royal Institute of Navigation reported in January 2026 that at least two collisions or groundings reported in mainstream media during 2025 were linked to GNSS interference. Its report also warned that hundreds of vessels are now affected daily across the Baltic, Strait of Hormuz and Red Sea regions.
GPS, AIS and container tracking are not the same thing
Three data layers are often mixed together on one tracking screen, but they do different jobs:
- GNSS position is calculated on the vessel from satellite signals. It can be jammed or spoofed.
- AIS position is broadcast by the vessel. It usually takes position and timing from the ship's GNSS receiver, so a false GNSS fix can appear in AIS data.
- Container milestones come from operational events such as terminal gate moves, loading confirmations, vessel departure messages, discharge scans and empty returns. They are generally separate from the ship's live position.
This distinction matters. A spoofed AIS position can make the vessel map wrong without changing the fact that your container was loaded on a named ship at a recorded port. Likewise, a carrier's discharge event can be valid even if the vessel's preceding track contains gaps or impossible jumps. The most reliable view combines the sources instead of treating any single feed as the whole shipment record.
What a suspicious track looks like
You do not need to diagnose electronic warfare from your desk, but a few patterns should stop you from taking the map literally:
- The vessel suddenly jumps hundreds of kilometres and then returns to its previous route.
- The position appears on land, at an airport, beside a government site or at the exact same point as many unrelated ships.
- The reported speed or course would be physically impossible for that vessel.
- AIS disappears for a period while nearby ships show similar gaps or distorted tracks.
- The live dot conflicts with recent port-call records, radar-based reporting or a confirmed carrier milestone.
A missing position is not automatically suspicious. Satellite AIS coverage varies, equipment can fail, and vessels can experience normal transmission gaps. Spoofing is more likely when several independent signs conflict at once, especially in a region already covered by navigation warnings.
Which shipment data should you trust
Start with confirmed operational milestones. A terminal gate-in, loaded-on-vessel event, departure message or discharge scan records a physical handling event. These events can still arrive late, be corrected or be mapped inconsistently by different carriers, but a GNSS transmitter does not create them simply by moving the vessel's coordinates.
Next, compare the vessel position with its port-call history, destination, course and ETA trend. One impossible coordinate should carry less weight than a consistent sequence of operational events. If the ship's dot jumps to land but the next confirmed port call and carrier schedule remain plausible, do not cancel trucking or change customer commitments on the map alone.
Use corroboration, not confidence theatre
A precise latitude and longitude can still be false. Trust rises when independent sources agree: carrier milestone, terminal event, vessel course, port call and schedule update. If only the position dot changes, treat it as an anomaly until another source confirms a real voyage change.
How spoofing can affect your operation
Most shippers will not steer a vessel, but bad position data can still reach your planning process. An automated ETA model may react to an impossible location. Customer-service teams may report a false diversion. A sanctions-screening system can associate the wrong vessel with a restricted area or another ship's identity. Insurers and banks may pause a transaction while the anomaly is investigated.
In one reported 2025 case, a tanker owner's location data was copied by a sanctioned vessel, which contributed to the legitimate ship being placed on a US sanctions list before the error was corrected. Another vessel's position reportedly shifted from waters off Fujairah to Iran's Kharg Island, leaving its owner facing blocked financial transactions for 45 days. The commercial harm came from systems acting on the signal, not from the ship physically sailing to the false location.
What shippers should do when the map looks wrong
- Do not act on one coordinate. Check whether the carrier milestone, destination, speed, course and recent port calls support the same story.
- Check maritime advisories. Coastal authorities, NAVTEX warnings and maritime security centres publish known GNSS interference areas.
- Ask the carrier or forwarder for confirmation. For a material diversion or delay, request the latest operational message rather than a screenshot of the same AIS feed.
- Protect downstream plans. Keep trucking and warehouse arrangements tied to confirmed arrival and discharge events, not only the vessel's map position.
- Record the anomaly. Save the time, coordinates and conflicting milestones. That evidence helps if an insurer, bank, customer or sanctions-screening provider questions the shipment later.
- Use exception-based tracking. A platform that presents milestones, AIS movement and ETA changes together makes contradictions easier to spot than a standalone vessel map.
The bottom line
GPS spoofing can make a real ship appear in an impossible place, and in 2026 the problem is affecting vessels at a scale the industry can no longer dismiss. But a false vessel coordinate does not automatically make every part of your container record false. Separate GNSS from AIS, and AIS from operational milestones. When the sources disagree, trust confirmed handling events and corroborated movement over one precise-looking dot. Good shipment visibility is not about believing more data. It is about knowing which data deserves to change your plan.