RFI affecting GBAS generally includes:

• Unintentional interference

  • Personal electronics and consumer devices

  • Nearby RF systems and emitters

  • Adjacent-band activity

  • Industrial equipment

• Intentional interference

  • Jammers

  • Spoofing devices

  • Deliberate GNSS-focused attacks

Effects vary from mild degradation of GNSS measurements up to complete loss of usable signals or denial of GBAS service.

RFI can affect GBAS in multiple ways:

• degradation of GPS/GNSS carrier tracking

• increased noise and loss of lock at the reference receivers

• elevated pseudorange errors and ionospheric correction uncertainty

• VDB message degradation or data dropouts

• increased protection levels (availability reduction)

• triggering of integrity or continuity alerts

In severe cases, GBAS can become temporarily unavailable, with GLS approaches reverting to ILS or other backup procedures.

Modern GBAS installations incorporate:

• reference-receiver quality monitoring

• signal-to-noise and tracking health monitoring

• anomaly detectors against excessive noise or loss of satellites

• ionospheric threat and gradient monitoring

• FDE (fault-detection and exclusion) algorithms in both ground and airborne systems

These monitors help detect degraded conditions early and prevent hazardous misleading information from being provided to aircraft.

GBAS RFI mitigation combines site engineering, system design, and operational procedures:

Site and infrastructure

• strategic siting of GNSS antennas away from likely interference sources

• shielding and filtering techniques

• redundant receivers in diverse locations

• controlled RF environment within the airport perimeter

Ground-system design

• multi-frequency and multi-constellation processing

• robust tracking algorithms resilient to jamming

• adaptive interference suppression and quality thresholds

Operational measures

• NOTAMs and temporary service restrictions

• fallback to ILS or RNAV minima

• ATC and airport procedures for GBAS outages

• reporting mechanisms for repeated interference events

When RFI is detected or suspected:

• GBAS service status is annunciated

• GLS approaches may be restricted or suspended

• crews revert to ILS, RNAV or visual minima

• operational advisories may be issued

• ground systems may automatically downgrade or disable service

Operators, ATC, and airport authorities coordinate to ensure safe continuation of operations and rapid restoration when interference subsides.