Software-defined radio verifies secure satellite positioning watermark
Performance Characterization of Pulsar's Software-defined Watermark Verifier
Cryptography and Security
Summary
Satellite navigation systems need ways to confirm their signals are authentic to prevent spoofing or fake signals. The authors show how a special watermark embedded in Pulsar's satellite signals can be checked using software-defined radios, making it possible to verify signal authenticity in real-time. Their experiments with live data from early Pulsar satellites prove this verification can work in commercial receivers. This advances secure satellite positioning by showing a practical method to ensure trustworthy timing and location services.
What this means in practice
- •For gnss receiver engineers: Integrate watermark verification into GNSS receivers to detect and authenticate Pulsar satellite signals in real-time.$Commercial implications: Enables commercial GNSS manufacturers to build secure devices that verify Pulsar's authenticated navigation signals, enhancing product trust.
- •For software-defined radio developers: Develop SDR-based tools to process and verify Pulsar's watermarked signals for research or field testing of secure navigation.
Authors
Jason Anderson, Kaz Gunning
Abstract
Pulsar provides the world's most secure PNT service by incorporating a Combinatorial Watermark into its ranging service. Under conservative signal conditions, Pulsar's Combinatorial Watermark, where 21 ranging code chips are inverted among the 1023, provides 32-bit authentication security each second. In this work, we present our software-defined radio (SDR) implementation of the Pulsar watermark processor. We discuss various threat models, multiple receiver architectures, implications to the receiver, and results from using Pulsar's SDR processing watermarked signals daily from the Pulsar-0 mission. Our results demonstrate the feasible implementation of Pulsar's watermark verification process in commercial GNSS receivers. This is an important milestone in making Xona's Pulsar service available to customers later this year after deployment of our first four production satellites.