Library·13 Aug 2026
GNSS spoofing and what the bridge actually sees
How a false position shows up on ECDIS, radar overlay and the GPS receiver — and what a watch officer should do before calling it a “glitch.” Draft for a longer note from sea.
This library note is the place for the long explanation. Digest items will link here when a spoofing or jamming report matters. The full piece — with examples from an LNGC bridge — will replace this stub.
What to look for
- COG/SOG that does not match the water or the Doppler log
- ECDIS own-ship jumping inland or onto another traffic lane
- Radar overlay no longer sitting on the charted coastline
- Two receivers disagreeing, or HDOP/quality flags changing together
Spoofing is not the same as a simple antenna fault. The useful habit is to cross-check, freeze a position, and tell the next watch what you saw — not to argue with the machine in the moment.
In the library & related
Contact: desk@seavanta.com — tips, corrections, I was there.