Authentication Concepts for Satellite-Based Augmentation Systems

The main focus of Satellite-Based Augmentation Systems has been the provision of integrity to the GNSS signals. However, the sensibility towards interference is growing within the GNSS community, as it becomes day by day more realistic, more feasible and cheaper. The purpose of this paper is to present a framework for designing SBAS authentication and to present innovative solutions. The paper will initially outline the threats to be mitigated, with emphasis on those specific to SBAS. The work will then focus on signals and signal components that could support authentication, its adequacy and the margin of maneuver for implementation. Subsequently, the paper will present some authentication approaches and discuss their adequacy for the SBAS service. Finally, the paper will discuss the impact of authentication for the SBAS users. Finally, some concrete implementation proposals will be presented and its bit-level implementation and their performance will be characterized, concluding with some recommendations. The paper is based on the activities of the EAST project (EGNOS Authentication Security Testbed), therefore most of the considerations are based on the European SBAS service EGNOS.