Authentication of GPS Modernized Signals Using TESLA Chimera

Spoofing of Global Navigation Satellite System (GNSS) signals continues to grow as a threat to position, navigation, and timing (PNT) users globally, including safety-of-life and other critical infrastructure users. United States (U.S.) Presidential Space Policy Directive 7 includes direction for the U.S. government to pursue authentication solutions for Global Positioning System (GPS) PNT services. We propose a Timed Efficient Stream Loss-tolerant Authentication (TESLA) Chips-Message Robust Authentication (Chimera) based authentication approach for modernized GPS signals that would provide in-band authentication of ranging measurements and navigation message content. Specific modernized civil navigation messages formats and message broadcast schedules are proposed, with associated trade-offs for frequency of authentication events vs. bandwidth consumed. We also present the results of simulations characterizing performance metrics including timeliness of authentication events for a representative notional configuration.