Signal and Data Authentication Experiments on NTS-3

Abstract

The need for GNSS (Global Navigation Satellite System) signal and data authentication for civilian users and infrastructure has been well-documented, and various methods have been investigated for two decades, notably the work of Scott. This need has recently been stressed in Space Policy Directive 7, which points towards implementation of authentication methods. Recent work by the Advanced SatNav (Satellite Navigation) Technologies group at Air Force Research Laboratory (AFRL) Space Vehicles has worked to address this need with the creation of the Chimera (Chips Message Robust Authentication) protocol. Chimera jointly authenticates both the navigation data and the spreading code of a GPS civilian signal. Navigation Technology Satellite – 3 (NTS-3) presents the opportunity to explore the emerging signal and data authentication methods given by Chimera and its variations. This paper describes several authentication experiments planned on NTS-3, including baseline Chimera, Navigation Message Authentication (NMA) only, fast channel Chimera experiments, Chimera with the Timed Efficient Stream Loss-Tolerant Authentication (TESLA) protocol for data authentication, and experiments using a post-quantum digital signatures algorithm. We discuss recent progress in implementing these experiments in preparation for the NTS-3 flight. This preparation includes implementation in the L3Harris NTS-3 payload and in MITRE’s GNSS Test Architecture (GNSSTA) receiver.