# US 12,222,426 B2 · Method for detecting spoofing in a GNSS (global navigation satellite system) receiver, corresponding receiver apparatus method and computer program product > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,222,426 B2 - Document ID: US12222426B2 - Status: Granted - Kind: B2 - Application number: 17/953,869 - Filed: 2022-09-27 - Published: 2023-03-30 - Granted: 2025-02-11 - Earliest claimed: 2021-09-30 - Assignees: STMicroelectronics S.r.l. - Applicants: STMICROELECTRONICS S.r.l. - Inventors: Domenico Di Grazia; Fabio Pisoni - Web page: https://patentgrep.com/patent/US12222426B2 ## CPC - G01S 19/215: {issues related to spoofing} - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract A satellite tracking channel has a frequency loop tracking a carrier frequency of a satellite signal. A first indication of a spoofed signals is generated based on a determined satellite signal noise floor value associated with the satellite tracking channel and a tracking channel signal noise threshold associated with the satellite tracking channel. A second indication of a spoofed signal is generated based on a determining satellite tracking phase noise associated with the satellite tracking channel and a tracking channel phase noise threshold associated with the satellite tracking channel. Reception of a spoofed signal on the satellite tracking channel is detected based on the generated first indication of a spoofed signal and the generated second indication of the spoofed signal. ## Claims ### Claim 1 A method, comprising: determining a satellite signal noise floor value associated with a satellite tracking channel, the satellite tracking channel having a frequency loop tracking a carrier frequency of a satellite signal; comparing the determined satellite signal noise floor value with a tracking channel signal noise threshold associated with the satellite tracking channel; determining a satellite tracking phase noise associated with the satellite tracking channel; comparing the determined satellite tracking phase noise with a tracking channel phase noise threshold associated with the satellite tracking channel; detecting reception of a spoofed signal on the satellite tracking channel based on the comparing of the determined satellite signal noise floor value with the tracking channel signal noise threshold and the comparing of the determined satellite tracking phase noise with the tracking channel phase noise threshold; and responding to the comparing of the determined satellite signal noise floor value with the tracking channel signal noise threshold indicating the determined satellite signal noise floor value exceeds the tracking channel signal noise threshold and the comparing of the determined satellite tracking phase noise with the tracking channel phase noise threshold indicating the determined satellite tracking phase noise exceeds the tracking channel phase noise threshold by generating a signal indicating a spoofed signal has been detected on the satellite tracking channel. ### Claim 2 (depends on 1) The method of claim 1, wherein the comparing the determined satellite signal noise floor value with a tracking channel signal noise threshold associated with the satellite tracking channel comprises: determining a reference signal noise floor value; determining a ratio of the determined satellite signal noise floor value and the reference signal noise floor value; and comparing the determined ratio to the tracking channel signal noise threshold. ### Claim 3 (depends on 2) The method of claim 2, wherein the reference signal noise floor value is an average channel noise over a plurality of satellite signals being tracked. ### Claim 4 (depends on 3) The method according to claim 3, wherein said reference signal noise floor value is computed in the tracking channel using correlators integrating over a chip length and at a different Doppler frequency with respect to said frequency tracking loop. ### Claim 5 (depends on 1) The method according to claim 1, wherein said generating the signal indicating a spoofed signal has been detected on the satellite tracking channel includes setting a flag and quarantining the spoofed signal over a defined time interval. ### Claim 6 (depends on 5) The method according to claim 5, wherein the generating the signal indicating a spoofed signal has been detected on the satellite tracking channel includes sending a detection alert to a host processor of an autonomous driving system or of another navigation system. ### Claim 7 (depends on 1) The method of claim 1, wherein the satellite tracking channel is a tracking channel of a Global Navigation Satellite System (GNSS). ### Claim 8 A device, comprising: a memory; and signal processing circuitry coupled to the memory, wherein the signal processing circuitry, in operation: implements a satellite tracking channel having a frequency loop tracking a carrier frequency of a satellite signal; determines a satellite signal noise floor value associated with the satellite tracking generates a first indication of a spoofed signal based on the determined satellite signal noise floor value and a tracking channel signal noise threshold associated with the satellite tracking channel; determines a satellite tracking phase noise associated with the satellite tracking channel; generates a second indication of a spoofed signal based on the determined satellite tracking phase noise and a tracking channel phase noise threshold associated with the satellite tracking channel; and detects reception of a spoofed signal on the satellite tracking channel based on the generated first indication of a spoofed signal and the generated second indication of the spoofed signal. ### Claim 9 (depends on 8) The device of claim 8, wherein the signal processing circuitry, in operation, responds to the first indication of a spoofed signal indicating detection of a spoofed signal and the second indication of a spoofed signal indicating detection of a spoofed signal by generating a signal indicating a spoofed signal has been detected on the satellite tracking channel. ### Claim 10 (depends on 8) The device of claim 8, wherein the signal processing circuitry, in operation, generates the first indication of a spoofed signal by: determining a reference signal noise floor value; determining a ratio of the determined satellite signal noise floor value and the reference signal noise floor value; and comparing the determined ratio to the tracking channel signal noise threshold. ### Claim 11 (depends on 10) The device of claim 10, wherein the signal processing circuitry, in operation, determines the reference signal noise floor value by determining an average channel noise over a plurality of satellite signals being tracked. ### Claim 12 (depends on 11) The device according to claim 11, wherein said reference signal noise floor value is computed in the tracking channel using correlators integrating over a chip length and at a different Doppler frequency with respect to said frequency tracking loop. ### Claim 13 (depends on 9) The device according to claim 9, wherein the generating the signal indicating a spoofed signal has been detected on the satellite tracking channel includes setting a flag and quarantining the spoofed signal over a defined time interval. ### Claim 14 (depends on 13) The device according to claim 13, wherein the generating the signal indicating a spoofed signal has been detected on the satellite tracking channel includes sending a detection alert to a host processor of an autonomous driving system or of another navigation system. ### Claim 15 (depends on 8) The device of claim 8, wherein the satellite tracking channel is a tracking channel of a Global Navigation Satellite System (GNSS). ### Claim 16 A system, comprising: a host processor; and signal processing circuitry coupled to the host processor, wherein the signal processing circuitry, in operation: implements a satellite tracking channel having a frequency loop tracking a carrier frequency of a satellite signal; determines a satellite signal noise floor value associated with the satellite tracking channel; generates a first indication of a spoofed signal based on the determined satellite signal noise floor value and a tracking channel signal noise threshold associated with the satellite tracking channel; determines a satellite tracking phase noise associated with the satellite tracking generates a second indication of a spoofed signal based on the determined satellite tracking phase noise and a tracking channel phase noise threshold associated with the satellite tracking channel; and detects reception of a spoofed signal on the satellite tracking channel based on the generated first indication of a spoofed signal and the generated second indication of the spoofed signal. ### Claim 17 (depends on 16) The system of claim 16, wherein the signal processing circuitry, in operation, responds to the first indication of a spoofed signal indicating detection of a spoofed signal and the second indication of a spoofed signal indicating detection of a spoofed signal by generating a signal indicating a spoofed signal has been detected on the satellite tracking channel. ### Claim 18 (depends on 16) The system of claim 16, wherein the signal processing circuitry, in operation, generates the first indication of a spoofed signal by: determining a reference signal noise floor value; determining a ratio of the determined satellite signal noise floor value and the reference signal noise floor value; and comparing the determined ratio to the tracking channel signal noise threshold. ### Claim 19 (depends on 18) The system of claim 18, wherein the signal processing circuitry, in operation, determines the reference signal noise floor value by determining an average channel noise over a plurality of satellite signals being tracked. ### Claim 20 (depends on 16) The system according to claim 16, wherein the signal processing circuitry, in operation, responds to detection of a spoofed signal by sending a detection alert to the host processor. ### Claim 21 (depends on 20) The system of claim 20 wherein the host processor, in operation, implements a navigation system, and the signal processing circuitry, in operation, detects signals of a Global Navigation Satellite System (GNSS). ### Claim 22 A non-transitory computer-readable medium having contents which cause a signal processing system to perform a method, the method comprising: implementing a satellite tracking channel having a frequency loop tracking a carrier frequency of a satellite signal; determining a satellite signal noise floor value associated with the satellite tracking channel; generating a first indication of a spoofed signal based on the determined satellite signal noise floor value and a tracking channel signal noise threshold associated with the satellite tracking channel; determining a satellite tracking phase noise associated with the satellite tracking channel; generating a second indication of a spoofed signal based on the determined satellite tracking phase noise and a tracking channel phase noise threshold associated with the satellite tracking channel; and detecting reception of a spoofed signal on the satellite tracking channel based on the generated first indication of a spoofed signal and the generated second indication of the spoofed signal. ### Claim 23 (depends on 22) The non-transitory computer-readable medium of claim 22, wherein the method comprises responding to the first indication of a spoofed signal indicating detection of a spoofed signal and the second indication of a spoofed signal indicating detection of a spoofed signal by generating a signal indicating a spoofed signal has been detected on the satellite tracking channel. ### Claim 24 (depends on 22) The non-transitory computer-readable medium of claim 22, wherein the contents comprise instructions executed by a processor of the signal processing system.