Guidelines for Galileo Assisted Commercial Authentication Service Implementation

The European Global Navigation Satellite System (GNSS), Galileo, is currently developing and implementing new added-value services aiming to provide increased security and robustness against malicious attacks (e.g. spoofing), like Open Service Navigation Message Authentication (OSNMA), to authenticate the data symbols, or Commercial Authentication Service (CAS), to authenticate the ranging signal. This paper analyses the impact, from a signal-level performance, of the different parameters involved in the service definition of the Assisted Commercial Authentication Service (ACAS) mode, and presents some guidelines for the implementation of this new service, focusing on the acquisition procedure. We also offer some simulation results showing the performance in different scenarios.