Aircraft continuously broadcast how accurate they believe their own navigation position to be — a value called NACp. When GPS is jammed or spoofed, that figure collapses. This map bins every eligible aircraft report into hexagonal cells and colours each one by the share of aircraft that reported degraded accuracy.
Degraded means NACp < 8, the same threshold the FAA treats as non-compliant. Only ICAO-addressed aircraft above 10,000 ft are counted: ground traffic, light aircraft with older equipment, and FAA ground-station rebroadcasts all report poor accuracy for reasons that have nothing to do with interference.
Red does not always mean jamming. It means aircraft there reported poor navigation accuracy. That correlates strongly with known jamming, but equipment faults and military testing produce it too.
Unlike a daily map, this one updates continuously — an event that starts this morning is visible this morning, not tomorrow.
The hexagonal-aggregation approach was pioneered by John Wiseman's gpsjam.org, which has mapped this daily since 2022. Our cells use the same H3 grid at the same resolution so the two can be read against each other.