Three time spoofing algorithms for GNSS timing receivers and performance evaluation

Abstract

This study proposes three different time spoofing algorithms based on modified satellite position, modified pseudorange, and combined modified pseudorange and satellite position. Their effectiveness and performance are verified and evaluated via computational simulations and experiments using open-source data provided by the Curtin Group. The algorithm of modified pseudorange shows the best performance, with the average value of receiver clock bias offset from the offset expected by the spoofer being 5.72 × 10⁻⁸ m, and the average value of spatial change in the receiver position being 4.88 × 10⁻⁴ m, thus, fully achieving the purpose of time spoofing, i.e., spoofing causes the receiver clock bias to reach an offset as intended by spoofer. However, the target receiver could detect spoofing by assessing pseudorange time delay. The algorithm of modified satellite position shows the worst performance. The outcome of the combination algorithm is between that of the two other time spoofing algorithms; The latter two algorithms mentioned above have an average receiver clock bias offset from the spoofer’s intended offset being − 117.80 m and − 58.90 m, the average value of spatial change in the receiver position being 109.08 m and 54.55 m, thereby basically achieving the purpose of time spoofing, respectively. The algorithm of modified satellite position does not require pseudorange time delay addition, which could be done by modifying navigation message parameters, it was challenging for target receiver to detect any pseudorange time delay as spoofing. Hence, users who rely on time information should enhance the security and reliability of detecting time information.