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What’s new:
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“State of Global Aviation Safety” 2025 report from the International Civil Aviation Organization (ICAO). It includes a section about GNSS interference.
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From the report: “For the short term, it is not foreseen that the issue of the GNSS RFI can be fully resolved.”
Why it’s important: ICAO is the United Nations body that deals with civil aviation issues and safety. While most in the community already thought this, it is good to have such a leading organization say so out loud.
What else to know:
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As a U.N. body ICAO has a lot of gravitas, but little hard power. Member states may or may not act in accordance with ICAO recommendations.
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We are not sure how ICAO defines “the short term.” We expect that it will really be more like “a long while.”
State of Global Aviation Safety
Global Navigation Satellite System
Radio Frequency Interference (GNSS RFI)
The global navigation satellite system (GNSS) provides positioning, navigation and timing
information, and is the backbone of modern aviation. Until recently, most pilots and industry
professionals may have been unfamiliar with GNSS spoofing, but due to a rise in incidents, spoofing
has become a major concern in aviation. GNSS is not only crucial in aviation but to other
industries as well, including maritime, transport and agriculture.
GNSS vulnerability lies in its low transmission power. The GNSS signal from satellites is weak at
the receiver antenna, making it susceptible to interference. Services provided by conventional aids
can also be disrupted by interference, however, GNSS typically serves more aircraft simultaneously
and the interference may affect wider geographic areas. Furthermore, GNSS civil signals and data
messages are unencrypted, unauthenticated and lack security protocols leaving GNSS data vulnerable.
There are two forms of GNSS radio frequency interference (RFI): jamming and spoofing. Jamming
refers to intentional radio frequency interference that blocks GNSS receivers from locking onto
satellite signals, effectively rendering the system unusable or degraded for users in the affected
area. Spoofing, on the other hand, involves broadcasting GNSS-like signals that deceive avionics
into calculating incorrect positions and providing false guidance.
GNSS RFI continues to persist in several regions around the world, posing a significant and ongoing
risk to civil aviation. While some instances of interference may be associated with conflict zones,
many occurrences are unrelated to such areas, further complicating the challenge of addressing and
mitigating their impacts.
Recognizing GNSS vulnerabilities
ICAO has been working to develop recommendations and guidance on GNSS RFI since 2003. At its 41st Session, the ICAO Assembly adopted Resolution 41-8/C, Ensuring the resilience of ICAO CNS/ATM systems and services, outlining a comprehensive policy to strengthen the resiliency of ICAO CNS/ATM systems and services, with a particular focus on GNSS. Furthermore, Recommendation 2.2/2, Addressing global navigation satellite system interference and contingency planning was approved by the Fourteenth Air Navigation Conference (AN-Conf/14), held in Montréal from 26 August to 6 September 2024.
- The Convention on International Civil Aviation (Chicago Convention, Doc 7300) and International Telecommunication Union (ITU) Regulations protect GNSS frequencies for aviation use. Furthermore, ICAO and ITU have established a memorandum of cooperation that sets a framework for enhanced cooperation between ICAO and ITU in matters related to harmful interference to GNSS with a potential impact on international civil aviation safety. In March 2025, ITU, ICAO and the International Maritime Organization (IMO) issued a joint statement to United Nations Member States, urging them to protect GNSS from harmful interference and outlined five key actions that Member States are expected to take. The joint statement “Protection of the radio navigation satellite service from harmful interference” is available at https://www.icao.int/Newsroom/Pages/Protect-satellite-navigation-from-interference-UN-agencies-urge.aspx.
For the short term, it is not foreseen that the issue of the GNSS RFI can be fully resolved. Hence, efforts are being focused on mitigation. ICAO, other international organizations and aviation industry have identified several actions and measures to mitigate the impact and likelihood of GNSS RFI.
ICAO is working on developing further guidance on spoofing as well as updating the Performance-based Navigation (PBN) Manual (Doc 9613) to better address GNSS disruption and implement PBN when GNSS is not available. The mid- to long-term solutions include the use of GNSS data authentication to enhance resilience toward GNSS spoofing, and redefining alternative position navigation and timing (A-PNT) technology and complementary position navigation and timing (C-PNT) to build resilient navigation.
Conclusion
Member States should anticipate, regulate and mitigate GNSS RFI.
• Anticipate by planning for potential disruptions, fostering coordination with all relevant stakeholders and raising awareness on its impact.
• Regulate by establishing clear guidelines and enforcing policies to safeguard GNSS systems from interference.
• Mitigate by implementing necessary strategies and measures such as maintaining a network of conventional navigation aids to ensure the uninterrupted provision of safe, efficient and secure air navigation services.
