| CPC G01S 19/243 (2013.01) [G01S 19/015 (2013.01); G01S 19/07 (2013.01); G01S 19/08 (2013.01); G01S 19/10 (2013.01); G01S 19/256 (2013.01)] | 16 Claims |
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1. A GNSS receiver comprising:
processing circuitry configured to:
receive a GNSS signal broadcast from a GNSS satellite and to acquire a navigation message;
perform positioning calculation on the basis of a propagation delay, which is a time required for the GNSS signal transmitted from the GNSS satellite, to reach an antenna;
store a reference timing that is a timing at which a navigation message of a predetermined type is received; and
determine that a GNSS signal including a subsequent navigation message is a spoofed GNSS signal when a timing difference, which is a difference between predicted reception timing of the next and subsequent navigation messages of same type predicted based on the stored reference timing and actual reception timing of navigation messages of same type after the reference timing, deviates from a predetermined time threshold range, until the timing difference falls within the predetermined time threshold range, wherein
when the GNSS signal is not determined to be the spoofed GNSS signal, the reference timing is updated based on the actual reception timing of the navigation messages, and
when the GNSS signal is determined to be the spoofed GNSS signal, the reference timing is not updated based on the actual reception timing of the navigation messages.
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