GNSS (Global Navigation Satellite System)

GNSS underpins a large part of contemporary air navigation. Receivers compute an aircraft's position by measuring the time taken for signals to arrive from multiple satellites, and that position feeds navigation displays, flight management systems, satellite-based approach procedures and surveillance systems such as ADS-B. Because the signals also carry precise time, GNSS additionally serves as a timing reference for avionics and ground infrastructure.

The dependence on GNSS is also its vulnerability. The signals arrive extremely weak after travelling from medium Earth orbit, so they can be overwhelmed by jamming or imitated by spoofing. Loss or corruption of GNSS can degrade navigation accuracy, invalidate satellite-based approaches and create discrepancies between satellite-derived and inertial position, increasing crew workload and, in places, forcing reversion to conventional navigation aids.

GNSS is the umbrella that GPS jamming and spoofing attack, and interference is now a routine feature of airspace near conflict and militarised regions. AeroVigil treats reported GNSS interference as an airspace-risk signal, associating jamming and spoofing advisories with the regions and routes where navigation integrity may be degraded before dispatch.