SBAS Simulation Platform for Authentication Reliable Concepts
Background & Objectives
The European Commission is exploring the possibility of improving the security of the SBAS service. SBAS data is currently trusted by end users, even if the navigation data (and signals) are not protected. The objective of the SPARC project is to identify a viable solution to authenticate the SBAS messages, when broadcast by the GEO satellites, possibly providing authentication also for the GNSS constellations augmented by SBAS. SPARC is a procurement launched by EC under the H2020 Framework Programme and it is technically managed by GSA.
Satellite based augmentation systems (SBAS) have been conceived to support safety of life operations in aviation by broadcasting GNSS differential corrections and integrity information. They are used mostly during precision approach. SBAS systems are regional systems, such as EGNOS in Europe and WAAS in the United States, among others. SBAS transmits a data signal in L1 frequency (1,575.42 MHz) and the next generation SBAS service will provide a dual frequency multi constellation (DFMC) service through data broadcast on L5 frequency (1,176.45 MHz) in 2025.
The increasing amount of radio frequency interference (RFI) and cyber-attacks to navigation systems is an emerging trend that can threaten receiver operation. The signal broadcast by the SBAS service can be subject to falsification. Since SBAS data is trusted by the user, erroneous data would affect the computation of the navigation solution, in a manner that is not detectable by the traditional techniques available for GNSS. This creates a risk for any SBAS user, including civil aviation and safety-critical applications. Authentication techniques can mitigate some of these threats.
The purpose of the SPARC project is to identify a viable solution to authenticate SBAS data, when broadcast by the GEO satellites, possibly providing authentication also for the GNSS core constellations. SPARC follows the previous H2020 project on EGNOS Authentication (EAST).
The project includes three iterations of the design with the following steps:
- The analysis of the external requirements. The purpose of this analysis is to consider the information available from the different organizations and stakeholders defining the aviation operational needs and developing SBAS standards. This is a fundamental step to identify a solution meeting the operational needs and current status of the standardization process.
- The analysis of the technical drivers. This activity aims at identifying which technical requirement drives the design of the authentication technique; these technical requirements must be compatible with the current state of the SBAS technologies, the SBAS standardization process and the aviation community requirements.
- The definition of the authentication techniques. The consortium will design and test techniques for the authentication of the SBAS messages and possibly also GNSS navigation data and will determine their impact on the SBAS availability or continuity performance. The broadcast of authentication data is done through the SBAS satellite communication channels. The project will explore the transmission of the authentication data exploiting existing data channel and also new data channels.
The project includes the development of a Simulation Environment capable of generating the whole SBAS and GNSS navigation chain (including GPS and Galileo constellations). The Simulation Environment allows to test each authentication solution to assess the impact on the SBAS services. It can work faster that real time or real time modes to provide statistically meaningful results from synthetic and real data for the metrics of interest.