Independent, reproducible monitoring of GNSS interference affecting civil aviation.
Satellite navigation signals reach an aircraft receiver extremely weak — roughly the power of a car headlight seen from twenty thousand kilometres away. They are correspondingly easy to disrupt.
Episodes of degraded satellite navigation affecting commercial aviation over parts of Europe have been reported publicly by airlines, aviation authorities and the trade press. Individual accounts exist. What does not is a continuous, independent, reproducible record of where and when aircraft reported degraded navigation integrity — one built to survive being challenged, and held by someone with no stake in the answer.
GNSS Observatory is being built to be that record.
Aircraft broadcast their position continuously over ADS-B, derived from onboard GNSS receivers. Those broadcasts also carry navigation integrity fields — the receiver's own assessment of how far its reported position can be trusted.
When reception degrades, that self-assessment falls, and the aircraft broadcasts the degradation to anyone listening. The effect publishes its own evidence. We read those public broadcasts and look for populations of aircraft whose navigation integrity falls together, in the same airspace, at the same time — then record the result in a form that can be re-derived and audited later.
A free, openly accessible view of where aircraft have reported degraded navigation integrity.
Open to anyone
Detailed records of individual episodes — airspace, time bounds, the underlying evidence, and the exact software version that produced them.
Airlines · insurers · legal · regulators
A programmatic interface and monitoring notifications, for organisations that need this inside their own systems.
Operations · routing · analytics platforms
Technical feasibility was assessed against real archive data in August 2026. The processing pipeline is being built now.
No findings are published on this site yet, and none will be until they have been evaluated against independently documented events.
If this would be useful to you, say so now. Early conversations shape what gets built first, and we will tell you directly when there is something to see.
Particularly relevant if you work in airline operations or flight safety, aviation insurance, air navigation services, regulation, accident investigation, maritime operations — or you are a journalist covering the subject.
These are design rules rather than aspirations. They exist because the failure modes are worse than the missed detections — and because they are what allows a finding to survive being challenged.
The data processed consists of transponder broadcasts made openly by aircraft: position, altitude, velocity, and navigation integrity values, together with the transponder's assigned address. It contains no passenger or crew information, and none is derived.
Analysis is carried out at the level of airspace and populations of aircraft, not individual flights, and individual aircraft are not identified in the public map or in public findings.
A transponder address can, in some cases, relate to an identifiable person — for example where an aircraft is privately owned. Where it does, processing is carried out on the basis of legitimate interests under Article 6(1)(f) GDPR: the independent documentation of navigation interference affecting aviation safety, using data already broadcast openly and published by others.
You may object to that processing at any time. An owner or operator may request exclusion, and the aircraft will be removed from processing and from any published output. Requests go to the contact address above. A full privacy notice will be published before any findings are.
This site sets no cookies, loads no third-party resources, and performs no tracking.
GNSS Observatory is not an aviation information service. Nothing published here is certified, validated for operational use, or suitable for navigation, flight planning, dispatch, or any safety-of-flight decision. Authoritative information about GNSS availability is issued by the relevant national aviation authorities and air navigation service providers, through NOTAMs and equivalent channels. Always use those.
GNSS Observatory is independent and is not affiliated with, endorsed by, or acting on behalf of any government, aviation authority, air navigation service provider, or aircraft operator.