Long-Term Actions (2030 Onward)

Objective: To ensure the resilience of aviation operations in the presence of GNSS RFI through the development and integration of technological enhancements across GNSS, along with independent timing sources. Key actions include:

1.    Complementary Positioning, Navigation and Timing (C-PNT)

Assembly Resolution A41-8, Appendix C (Operative Clauses 1, 3, 4, and 5), emphasizes the need for enhancing resilience to interference by maximizing the integration of all suitable ground infrastructure, space infrastructure and airborne components in a complementary and cooperative manner, to be as robust as possible to cases of satellite-based service disruption or environments where false or deceptive signals are present.

To deliver guiding principles to infrastructure providers, and ensuring that space-based, ground-based and airborne capabilities are provided efficiently, ICAO is working toward a concept of complementary PNT (C-PNT), which aims to improve multi-sensor integration. This will ensure that individual airborne systems cannot corrupt others; achieve a suitable balance between terrestrial, aircraft autonomous capabilities (inertial navigation system (INS) and other sensors) and space-based capabilities (legacy and dual-frequency multi-constellation (DFMC) GNSS); and facilitate multi-sensor integration and complementary performance monitoring to take the maximum advantage of all available sensors.

Additionally, C-PNT introduces the use of precise and GNSS independent time sources, enhancing the integrity of both air and ground systems by protecting them from corrupted time information when GNSS signals are compromised. For a seamless implementation, aircraft and avionics manufacturers must carry out the necessary upgrades, preventing the cross-contamination of avionics sensors caused by GNSS RFI. These ongoing actions for the C-PNT are expected be completed by 2030.

2- GALILEO Open System Navigation Message Authentication (GALILEO OSNMA)

The European navigation satellite system Galileo is progressing towards the declaration of the Initial Service for Open Service Navigation Message Authentication (OSNMA). OSNMA will increase the resilience and robustness of Galileo service provision, ensuring that the received navigation message genuinely originates from Galileo satellites, as an additional security layer.

It is envisaged that the Standards and Recommended Practices (SARPs) for Galileo OSNMA navigation data authentication feature will be applicable in 2028. Furthermore, it is expected that Galileo authentication could be supported by a future generation of GNSS Receivers, together with authentication of satellite-based augmentation systems (SBAS).

3- Satellite-based Augmentation System (SBAS) Authentication

SBAS is used to enhance navigational accuracy by providing GNSS differential corrections and integrity monitoring. However, current SBAS signals are unencrypted and may be vulnerable to falsification. To address the safety risk of SBAS falsification, ICAO started the development of SARPs for SBAS Authentication in 2017. It is envisaged that the validation of the SARPs for the optional new authentication feature will be finalized in November 2027 and will be applicable in 2029.

4- Dual-Frequency Multiple Constellations (DFMC) GNSS

DFMC GNSS enhances global navigation by utilizing signals from multiple satellite constellations, such as GPS, Galileo, GLONASS, and BeiDou. This approach improves accuracy, reliability, and resilience against interference compared to single-frequency systems. This will also help mitigate vulnerabilities in respect of RFI affecting a single frequency or constellation, ionospheric disturbances, and the risk of having insufficient satellites within a single constellation.

Although Amendment 93 to Annex 10, Volume I introduced provisions to support the implementation of DFMC GNSS, the timeline of industry developments suggests that the initial operational introduction of DFMC GNSS would begin to occur in the 2032 - 2035 timeframe. In the long term, it is expected that avionics capabilities will be available to enable the use of all DFMC GNSS elements and signals.