# US 10,120,080 B2 · Detection of spoofed satellite signals > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,120,080 B2 - Document ID: US10120080B2 - Status: Granted - Kind: B2 - Application number: 15/385,662 - Filed: 2016-12-20 - Published: 2017-04-13 - Granted: 2018-11-06 - Earliest claimed: 2013-10-30 - Assignees: Raytheon Company - Applicants: Raytheon Company - Inventors: Steven P. Davies - Web page: https://patentgrep.com/patent/US10120080B2 ## 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 technology is provided for detecting spoofed satellite signals. An aircraft may be equipped with a top antenna that is adapted to receive satellite signals and a bottom antenna that is adapted to receive terrestrial signals. A signal may be received on the top antenna and the bottom antenna. Relative signal strength between the top antenna and the bottom antenna may be used to differentiate satellite sourced signals from terrestrial sourced signals. ## Claims ### Claim 1 A method for detecting spoofed satellite signals, the method comprising: receiving a signal via a plurality of antennas, wherein the plurality of antennas are positioned on an aircraft; determining that the signal is a spoofed satellite signal based on a comparison of the signal strengths received via each of the plurality of antennas with a dynamic threshold; and determining an authenticated state when relative signal strengths associated with the signal meets the dynamic threshold for confirming that the signal is the authentic satellite signal. ### Claim 2 (depends on 1) The method of claim 1, further comprising using the dynamic threshold for determining that the signal is the spoofed satellite signal from the terrestrial source or an authentic satellite signal, wherein the dynamic threshold is based on at least one of: aircraft attitude, aircraft position, aircraft heading, and satellite position. ### Claim 3 (depends on 1) The method of claim 1, further comprising performing the comparison using an aircraft attitude to determine an expected relative signal strength between the plurality of antennas for an authentic satellite signal. ### Claim 4 (depends on 1) The method of claim 1, further comprising performing the comparison using at least one of aircraft position, aircraft heading, aircraft attitude, and satellite position to determine an expected relative signal strength between the plurality of antennas for an authentic satellite signal. ### Claim 5 (depends on 1) The method of claim 1, further comprising performing the comparison using an aircraft attitude to determine an expected relative signal strength between the plurality of antennas for the spoofed satellite signal from a terrestrial source. ### Claim 6 (depends on 1) The method of claim 1, further comprising performing the comparison using at least one of aircraft position, aircraft heading, aircraft attitude, and information on surrounding terrain to determine an expected relative signal strength between the plurality of antennas for the spoofed satellite signal from a terrestrial source. ### Claim 7 (depends on 1) The method of claim 1, wherein the plurality of antennas are positioned on an upper portion or a lower portion of the aircraft. ### Claim 8 (depends on 1) The method of claim 1, further comprising determining that the spoofed satellite signal is from a terrestrial signal source. ### Claim 9 A system for detecting spoofed satellite signals, the system comprising: a receiver configured to receive a signal via a plurality of antennas, wherein the plurality of antennas are positioned on an aircraft; a signal comparison module configured to compare the signal strengths received via the plurality of antennas with a dynamic threshold; a signal module configured to determine that the signal is a spoofed satellite signal when the signal strengths are compared against the dynamic threshold, wherein the signal module determines an authenticated state when relative signal strengths associated with the signals meet the dynamic threshold for confirming that the signal is the authentic satellite signal. ### Claim 10 (depends on 9) The system of claim 9, wherein the dynamic threshold is based on at least one of aircraft attitude, aircraft position, aircraft heading, and satellite position, or a combination of these. ### Claim 11 (depends on 9) The system of claim 9, wherein the dynamic threshold comprises aircraft attitude, and wherein the signal comparison module determines an expected relative signal strength between the plurality of antennas to identify an authentic satellite signal. ### Claim 12 (depends on 9) The system of claim 9, wherein the dynamic threshold comprises one of aircraft position, aircraft heading, aircraft attitude, and satellite position, and wherein the signal comparison module determines an expected relative signal strength between the plurality of antennas to identify an authentic satellite signal. ### Claim 13 (depends on 9) The system of claim 9, wherein the dynamic threshold comprises one of aircraft position, aircraft heading, aircraft attitude, and information on surrounding terrain, and wherein the signal comparison module determines an expected relative signal strength between the plurality of antennas for a spoofed satellite signal from a terrestrial source. ### Claim 14 (depends on 9) The system of claim 9, wherein one of the plurality of antennas is positioned on an upper portion of the aircraft, and one of the antennas is positioned on a lower portion of the aircraft. ### Claim 15 A method for detecting spoofed satellite signals, the method comprising: receiving a signal via a plurality of antennas, wherein the plurality of antennas are positioned on an aircraft; determining that the signal is a spoofed satellite signal based on a comparison of the signal strengths received via each of the plurality of antennas with a dynamic threshold; and determining a rejected state when relative signal strengths associated with the signal meets the dynamic threshold for confirming that the signal is a spoofed satellite signal. ### Claim 16 (depends on 15) The method of claim 15, further comprising using the dynamic threshold for determining that the signal is the spoofed satellite signal from a terrestrial source or an authentic satellite signal, wherein the dynamic threshold is based on at least one of: aircraft attitude, aircraft position, aircraft heading, and satellite position. ### Claim 17 (depends on 15) The method of claim 15, further comprising performing the comparison using an aircraft attitude to determine an expected relative signal strength between the plurality of antennas for an authentic satellite signal. ### Claim 18 (depends on 15) The method of claim 15, further comprising performing the comparison using at least one of aircraft position, aircraft heading, aircraft attitude, and satellite position to determine an expected relative signal strength between the plurality of antennas for an authentic satellite signal. ### Claim 19 (depends on 15) The method of claim 15, further comprising performing the comparison using an aircraft attitude to determine an expected relative signal strength between the plurality of antennas for the spoofed satellite signal from a terrestrial source. ### Claim 20 (depends on 15) The method of claim 15, further comprising performing the comparison using at least one of aircraft position, aircraft heading, aircraft attitude, and information on surrounding terrain to determine an expected relative signal strength between the plurality of antennas for the spoofed satellite signal from a terrestrial source. ### Claim 21 A method for detecting spoofed satellite signals, the method comprising: receiving a signal via a plurality of antennas, wherein the plurality of antennas are positioned on an aircraft; determining that the signal is a spoofed satellite signal based on a comparison of the signal strengths received via each of the plurality of antennas with a dynamic threshold; and determining an unknown state when relative signal strengths associated with the signal does not meet the dynamic threshold for confirming that the signal is an authentic satellite signal nor for confirming that the signal is a spoofed satellite signal from a terrestrial source. ### Claim 22 (depends on 21) The method of claim 21, further comprising using the dynamic threshold for determining that the signal is the spoofed satellite signal from a terrestrial source or an authentic satellite signal, wherein the dynamic threshold is based on at least one of: aircraft attitude, aircraft position, aircraft heading, and satellite position. ### Claim 23 (depends on 21) The method of claim 21, further comprising performing the comparison using an aircraft attitude to determine an expected relative signal strength between the plurality of antennas for an authentic satellite signal. ### Claim 24 (depends on 21) The method of claim 21, further comprising performing the comparison using at least one of aircraft position, aircraft heading, aircraft attitude, and satellite position to determine an expected relative signal strength between the plurality of antennas for an authentic satellite signal. ### Claim 25 (depends on 21) The method of claim 21, further comprising performing the comparison using an aircraft attitude to determine an expected relative signal strength between the plurality of antennas for the spoofed satellite signal from a terrestrial source. ### Claim 26 (depends on 21) The method of claim 21, further comprising performing the comparison using at least one of aircraft position, aircraft heading, aircraft attitude, and information on surrounding terrain to determine an expected relative signal strength between the plurality of antennas for the spoofed satellite signal from a terrestrial source. ### Claim 27 A system for detecting spoofed satellite signals, the system comprising: a receiver configured to receive a signal via a plurality of antennas, wherein the plurality of antennas are positioned on an aircraft; a signal comparison module configured to compare the signal strengths received via the plurality of antennas with a dynamic threshold; and a signal module configured to determine that the signal is a spoofed satellite signal when the signal strengths are compared against the dynamic threshold, wherein the signal module determines a rejected state when relative signal strengths associated with the signals meet the dynamic threshold for confirming that the signal is the spoofed satellite signal from a terrestrial source. ### Claim 28 (depends on 27) The system of claim 27, wherein the dynamic threshold is based on at least one of aircraft attitude, aircraft position, aircraft heading, and satellite position, or a combination of these. ### Claim 29 (depends on 27) The system of claim 27, wherein the dynamic threshold comprises aircraft attitude, and wherein the signal comparison module determines an expected relative signal strength between the plurality of antennas to identify an authentic satellite signal. ### Claim 30 (depends on 27) The system of claim 27, wherein the dynamic threshold comprises one of aircraft position, aircraft heading, aircraft attitude, and satellite position, and wherein the signal comparison module determines an expected relative signal strength between the plurality of antennas to identify an authentic satellite signal. ### Claim 31 (depends on 27) The system of claim 27, wherein the dynamic threshold comprises one of aircraft position, aircraft heading, aircraft attitude, and information on surrounding terrain, and wherein the signal comparison module determines an expected relative signal strength between the plurality of antennas for a spoofed satellite signal from a terrestrial source. ### Claim 32 (depends on 27) The system of claim 27, wherein one of the plurality of antennas is positioned on an upper portion of the aircraft, and one of the antennas is positioned on a lower portion of the aircraft. ### Claim 33 A system for detecting spoofed satellite signals, the system comprising: a receiver configured to receive a signal via a plurality of antennas, wherein the plurality of antennas are positioned on an aircraft; a signal comparison module configured to compare the signal strengths received via the plurality of antennas with a dynamic threshold; and a signal module configured to determine that the signal is a spoofed satellite signal when the signal strengths are compared against the dynamic threshold, wherein the signal module determines an unknown state when relative signal strengths associated with the signals do not meet the dynamic threshold for confirming that the signal is the authentic satellite signal, nor for confirming that the signal is the spoofed satellite signal from a terrestrial source. ### Claim 34 (depends on 33) The system of claim 33, wherein the dynamic threshold is based on at least one of aircraft attitude, aircraft position, aircraft heading, and satellite position, or a combination of these. ### Claim 35 (depends on 33) The system of claim 33, wherein the dynamic threshold comprises aircraft attitude, and wherein the signal comparison module determines an expected relative signal strength between the plurality of antennas to identify an authentic satellite signal. ### Claim 36 (depends on 33) The system of claim 33, wherein the dynamic threshold comprises one of aircraft position, aircraft heading, aircraft attitude, and satellite position, and wherein the signal comparison module determines an expected relative signal strength between the plurality of antennas to identify an authentic satellite signal. ### Claim 37 (depends on 33) The system of claim 33, wherein the dynamic threshold comprises one of aircraft position, aircraft heading, aircraft attitude, and information on surrounding terrain, and wherein the signal comparison module determines an expected relative signal strength between the plurality of antennas for a spoofed satellite signal from a terrestrial source. ### Claim 38 (depends on 33) The system of claim 33, wherein one of the plurality of antennas is positioned on an upper portion of the aircraft, and one of the antennas is positioned on a lower portion of the aircraft.