Detection of GNSS Spoofing using NMEA Messages

Many devices are dependent on the positioning, velocity, and time information provided by Global Navigation Satellite Systems (GNSS) receivers. Although the accuracy and integrity of GNSS receivers have improved over the years, the susceptibility of the receivers to signal interferences such as GNSS jamming and spoofing remains a significant issue to various systems. In this study, the authors successfully spoof a commercial u-blox GNSS receiver, and the GNSS receivers inside multiple Android smartphones, and an iPhone. In addition, it is shown that the spoofing of GNSS receivers is sufficient to successfully spoof the fused location engines of the smartphones which use not only GNSS, but a combination of other location sources such as network positioning and inertial sensors. Following the spoofing, the authors suggest how the National Marine Electronics Association (NMEA) messages provided by the GNSS receivers can be utilized to detect instances of spoofing and identify suspicious potentially spoofed satellite signals. The use of NMEA messages instead of raw GNSS measurements to detect potential GNSS spoofing allows us to assess the utility of the currently available resources, and bypass large computation loads required to obtain and process raw measurements.