How to Read GNSS Interference Maps

The layer measures effects, not the transmitter

Most public GNSS interference products infer disruption from aircraft navigation quality, receiver reports, or aggregated anomalies. They show where users experienced suspicious positioning behavior. They do not normally reveal the jammer's exact location, operator, power, or purpose.

A colored area should therefore be described as observed or inferred interference. Turning it into a claim about a particular military unit or political actor requires evidence outside the map and should never be automated from the polygon alone.

Coverage follows observers

A region with many reporting aircraft and receivers can produce detailed cells. A region with little cooperative traffic may appear clean even when interference exists. The absence of colored cells is not equivalent to a verified absence of disruption.

Coverage can also change by time of day as routes, fleets, and data-sharing participants change. Comparing two snapshots without checking observation density can mistake a change in reporting for a change in interference.

Why polygons can look blocky

Many sources aggregate observations into geographic bins to protect individual tracks, reduce noise, and make large datasets practical. SkyWatch may merge adjacent cells or outline clusters for readability. The resulting boundary reflects the resolution of the product, not a precise edge on the ground.

Zooming does not create additional measurement detail. A large cell remains a large cell even when the basemap underneath becomes sharper. Tooltips should expose the available score, observation window, and source rather than imply street-level accuracy.

False positives and cross-checks

Navigation anomalies can arise from receiver faults, aircraft equipment, multipath near terrain or structures, incomplete data, and ordinary statistical outliers. A useful product requires repeated observations, minimum sample counts, and temporal consistency before presenting a strong area.

Cross-check the shape against aviation notices, reports from more than one fleet or provider, movement of the affected area, and changes in the number of observers. Independent agreement raises confidence; a single weak cell should remain a lead rather than a conclusion.

A careful public description

Prefer wording such as 'public observations indicate degraded GNSS performance in this area during the displayed window.' Avoid claiming that every device is affected or that navigation is impossible.

Operational users should rely on certified navigation procedures, official notices, and their own equipment. SkyWatch is a situational-awareness aid for comparing public signals, not a navigation safety system.