Intermodulation Component-Based Authentication for Civilian GNSS Signals.

Area of Science:

• Navigation Systems
• Signal Processing
• Cybersecurity

Background:

• Civilian Global Navigation Satellite System (GNSS) receivers face authentication challenges.
• Existing authentication schemes often require modernized signals or access to authorized spreading codes, limiting civilian use.
• Intermodulation components from constant envelope modulation offer a novel, unexploited feature for authentication.

Purpose of the Study:

• To propose and analyze a novel navigation signal authentication scheme for civilian GNSS receivers.
• To leverage intermodulation components for signal authentication without relying on modernized signals or authorized codes.
• To evaluate the performance and security of the proposed scheme against existing methods.

Main Methods:

• Exploiting intermodulation components generated by constant envelope modulation in GNSS signals.
• Utilizing the unpredictable spreading code of intermodulation components as an authentication feature.
• Employing a correlation-based hypothesis test for signal authentication after obtaining the intermodulation spreading code via a communication link.
• Analyzing the scheme using the GPS L1 signal and comparing performance with Chimera, OSNMA, and PROSPA.

Main Results:

• The proposed scheme provides authentication comparable in robustness and security to the Chimera system.
• It successfully avoids the authorization restrictions inherent in schemes requiring authorized spreading codes.
• Achieves high authentication efficiency (exceeding Chimera's fast channel) with significantly reduced data storage requirements under specified conditions (63.82 kbps, 30 dB-Hz C/N0).

Conclusions:

• The proposed intermodulation-based authentication scheme offers a viable and secure solution for civilian GNSS receivers.
• It presents a practical alternative to existing methods by circumventing the need for authorized signal access.
• The scheme demonstrates strong performance metrics and reduced resource demands, making it suitable for widespread civilian adoption.