Receiver Protocol and Pitfalls of NMA and SCA Processing Under Spoofing Conditions for Future GNSS Signals Authentication

The scope of the paper is to provide a generic receiver architecture that can cope with future Navigation Message Authentication (NMA) and Spreading Code Authentication (SCA) for the open service (OS) Global Navigation Satellite System (GNSS) signals. The authentication proposals can be divided in those that suggest the encryption of the navigation data, those that suggest encryption of the spreading code, and those that suggest combining both encryptions. However, on the receiver side, the mere implementation of such algorithms is not enough to identify a spoofing attack, and therefore, further receiver capabilities need to be considered when defining a GNSS signal authentication receiver architecture. The primary goal of the investigation is to define a receiver architecture capable of detecting spoofing attacks and to identify the possible pitfalls that affect the receiver performance. For this purpose, a new signal is defined to provide authentication capabilities to a mass-market receiver. The proposed receiver architecture is then used with the newly defined authentication signal to test the spoofing detection capabilities under different receiver conditions, and attack scenarios. The scope of the verifications is to identify the possible pitfalls that might wrongfully affect to the spoofing detection mechanism.