Analysis of global navigation satellite system position deviation under spoofing

The position deviation in global navigation satellite system (GNSS) positioning, which is subject to spoofing, is analysed. A spoofer transmits GNSS-like signals to a navigation receiver and may cause a significant position deviation in navigation computation. Although GNSS receivers can be equipped with certain receiver autonomous integrity monitoring (RAIM) schemes to provide fault detection and isolation functions, it is possible that the misleading information because of spoofers may enter a GNSS receiver without being detected. As spoofers may inject erroneous pseudo-range measurements to the navigation receiver with a false message, it is important to assess the spoofing effect on the resulting position. An optimisation approach is adopted to determine the worst-case misleading message and the resulting position deviation. A vulnerability index against spoofing is defined for the assessment of the position deviation in a spoofed environment.