Spoofing Detection in GNSS Receivers through Cross-Ambiguity Function Monitoring

Searching for the presence of multiple peaks within the cross-ambiguity function (CAF) of a received GNSS signal against a known GNSS pseudorandom noise (PRN) code is a well-known technique to detect the presence of spoofing. However, little is available in the public literature on the performance capabilities and limitations of this technique. This paper presents a performance assessment of CAF monitoring for spoofing detection with a focus on the GPS C/A-code and L5 signals, which are the two GPS signals that will be utilized by future airborne equipment now being standardized.