Patent ID: 11906634
Assignee: NOVATEL INC.
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A computer implemented method to determine whether a spoofing attack is occurring, the computer implemented method comprising:
receiving signals at a first antenna and a second antenna; and
performing a carrier phase authentication procedure on the signals, wherein the carrier phase authentication procedure comprises:
measuring a first double difference of a first carrier phase measurement of the signals received at the first antenna and the second antenna;
determining whether a first value corresponding to the first double difference of the first carrier phase measurement exceeds a predefined carrier phase threshold;
determining that the first value of the first double difference of the first carrier phase measurement does not exceed the predefined carrier phase threshold;
initiating an observation window that lasts a predefined amount of time after determining that the first value of the first double difference does not exceed the predefined carrier phase threshold,
determining that the signals are authentic navigation signals if (1) a signal difference variance value indicates that a current single difference, obtained during the observation window, it time variant in relation to a previous single difference of (2) a double difference variance value indicates that a current double difference, obtained during the observation window, is time variant in relation to a previous double difference, and
determining that the signals are spoofing signals if (1) the observation window has ended, (2) the single difference variance value indicates that the current single difference is not time variant in relation to the previous single difference, and (3) the double difference variance value indicates that the current double difference is not time variant in relation to the previous double difference.