Abstract: A GNSS enabled device configured to process pulse per second (PPS) signals, in particular from a GNSS satellite constellation to determine a global position of the GNSS enabled device. The device comprises a GNSS receiver module configured to acquire the PPS signals, a computing unit, and a reference timer comprising a local reference clock and a timer circuit to measure periods of said PPS signals. The computing unit and reference timer are configured to measure a variance in jitter of said PPS signals to determine whether the received PPS signal is genuine or spoofed.