Global Navigation Satellite System Interferometric Reflectometry Signature-Based Defense

A global navigation satellite system (GNSS) interferometric reflectometry (IR) signature-based defense system comprising:

• a first GNSS antenna mounted on a first antenna mast at a geographic location;
• a first GNSS receiver that is communicatively coupled to the at least one GNSS antenna;
• a memory containing:
• (i) a positioning, navigation and timing (PNT) module;
• and (ii) a GNSS-IR signature-based defense module;
• a controller communicatively coupled to the first receiver and the memory, the controller executing the PNT module and the GNSS-IR signature-based defense module to enable the GNSS-IR signature based defense system to:
• receive, the GNSS receiver, a first broadcast from a particular GNSS satellite during a particular earth orbit;
• determine identifying information for the particular GNSS satellite according to GNSS satellite communication protocols;
• measure line of sight and reflected signal strengths of the first broadcast of the particular GNSS satellite during a portion of the particular earth orbit to detect multipath variations that are characteristic for the geographic location;
• create a GNSS IR signatures associated with the particular GNSS satellite based on the measured broadcast;
• store the GNSS-IR signature in the memory;
• during a subsequent earth orbit, determine whether a second broadcast self-identified as being from the particular GNSS satellite matches the GNSS IR signature associated with the particular GNSS satellite;
• and
• in response to determining that the second broadcast matches the GNSS IR signature, update the GNSS IR signature in the memory at least in part using the second broadcast;
• and
• in response to determining that the second broadcast does not match the GNSS IR signature, generate an alert indicating spoofing of the particular GNSS satellite.