Frequency-domain code replica detection for a GNSS receiver

This paper addresses the problem of detecting the presence of spreading signal replica in GNSS receivers, a problem that is often related to the presence of non-authentic GNSS signals. In order to carry out the detection process, a super-resolution frequency-domain technique is proposed based on the well-known Pisarenko harmonic decomposition, which allows us to circumvent many of the problems encountered by non-parametric spectral methods in the presence of short data records. The proposed technique allows to detect the presence of signal replicas while at the same time, it provides an estimate of its frequencies which can be used for frequency tracking purposes in integrity monitoring applications. The performance of the proposed technique has been tested with real GNSS signals from a hardware simulator, confirming the capability of this technique to detect real-life code replicas, even when they are just a few Hz apart.