“…Spread spectrum security code (e.g., [32]) System Navigation message authentication (e.g., [32,33]) L1/L2 power level comparison (e.g., [34,35]) L1/L2 power level code phase comparison (e.g., [34]) Hardware DOA monitoring (e.g., [36,37]) Synthetic antenna array (e.g., [38]) Signal strength monitoring (e.g., [17,39]) Doppler monitoring (e.g., [40,41]) Code and phase rates consistency check (e.g., [34]) TOA monitoring (e.g., [17,42]) PRN code and data bit latency (e.g., [43][44][45]) Auxiliary peak tracking APT (e.g., [18]) Signal quality monitoring (e.g., [46][47][48]) Firmware Distribution analysis of correlator output (e.g., [49,50]) C/N 0 Monitoring (CNM) (e.g., [34,39]) Physical Cross-Check (PCC) (e.g., [51][52][53][54]) Clock Drift Monitoring (CDM) (e.g., [8,18]) Ephemeris Data Validation (EDV) (e.g., [34,55]) Software Pairwise Distance Monitoring (PDM) (e.g., [7,56]) Notation: Effective ( ), semi-effective ( ), and ineffective ( ) GPS spoofing detection regarding individual attacker models defined in Section 3.2, cf. Figure 2.…”