Patent attributes
The present invention provides a system and method for determining the authenticity of reported positions of GNSS receivers, such as aircraft equipped with GPS positioning devices, and provides an in-band verification capability for GNSS positions by tasking one or more GNSS satellites as designated authentication support (DAS) satellites that transmit corrupted ephemeris data in a pseudo-random error corrupted C/A signal on the L1 band, and the GNSS receivers determine authentication ranges to the DAS satellites and transmit the DAS authentication ranges as part of their position report. The surveillance system can verify the authenticity by comparing the transmitted authentication ranges to true authentication ranges determined using actual ephemeris data and the known C/A code pseudo-random error for the DAS satellites.
