GNSS spoofing detection and alert using SBAS satellites

A system comprising:

• at least one processor onboard a vehicle;
• a Global Navigation Satellite System (GNSS) receiver onboard the vehicle and operatively coupled with the at least one processor;
• and
• a GNSS spoofing detection module onboard the vehicle, the GNSS spoofing detection module including instructions to perform a method comprising:
• monitoring a plurality of satellite signals, from GNSS satellites and Satellite-based Augmentation System (SBAS) satellites, with the GNSS receiver;
• obtaining a current time and satellite orbital parameters from the GNSS receiver, based on real-time satellite signals received from the GNSS and SBAS satellites through a GNSS antenna;
• computing satellite orbital positions for the GNSS and SBAS satellites based on the current time and satellite orbital parameters from the GNSS receiver;
• retrieving past satellite orbital parameters from the GNSS receiver stored in a memory;
• calculating predicted satellite orbital positions for the GNSS and SBAS satellites based on the satellite orbital parameters with respect to the current time, and the past satellite orbital parameters stored in the memory;
• computing current satellite orbital positions for the GNSS and SBAS satellites based on current satellite signals from the GNSS and SBAS satellites received by the GNSS receiver;
• determining at least one first distance value between two or more of the GNSS and/or SBAS satellites based on the predicted satellite orbital positions;
• determining at least one second distance value between two or more of the GNSS and/or SBAS satellites based on the current satellite orbital positions;
• comparing the at least one first distance value and the at least one second distance value to obtain at least one discriminator value;
• determining whether the at least one discriminator value is greater than a threshold level;
• and
• outputting a spoofing alert signal when the at least one discriminator value is greater than the threshold level;
• wherein if a spoofer changes a SBAS satellite orbital position, then the changed SBAS satellite orbital position will be detected in a first validation step using the predicted satellite orbital position of the SBAS satellite;
• wherein if the spoofer changes a GNSS satellite orbital position without changing the SBAS satellite orbital position, then the changed GNSS satellite orbital position will be detected in a second validation step using the predicted satellite orbital position of the GNSS satellite;
• wherein if the spoofer changes the GNSS and SBAS satellite orbital positions together, then the changed GNSS and SBAS satellite orbital positions will be detected by prediction positioning using past ephemeris data for both the GNSS and SBAS satellites.