A method to detect at a GNSS receiver whether the received GNSS signals and navigation messages are the product of an attack. If there is evidence, as provided by the method described here, that the received signals and messages originate from adversarial devices, then receiver equipped with an instantiation of the method notifies the user or the computing platform that integrates the GNSS receiver that the calculated via the GNSS functionality position and time correction are not trustworthy. In other words, our method enables any GNSS receiver, for example, GPS, GLONASS, or Galileo, or any other GNSS system, to detect if the received navigation messages are the legitimate ones (from the satellites) or not (e.g., from attacker devices that generate fake messages that overwrite the legitimate messages). Based on this detection, neither the user and nor any application running in the computing platform is misled to utilize erroneous position information.