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EP-4735914-A1 - GPS SATELLITE SIGNAL AUTHENTICATION BASED ON RELATIVE GAIN USING BEAMFORMING ANTENNA ELECTRONICS

EP4735914A1EP 4735914 A1EP4735914 A1EP 4735914A1EP-4735914-A1

Abstract

Techniques for satellite signal authentication. In an example, a Global Positioning System (GPS) or global navigation satellite system (GNSS) includes antenna electronics, a processor, and a GPS or GNSS receiver. The antenna electronics is configured to provide, to the GPS or GNSS receiver, signals, wherein the signals comprise GPS or GNSS satellite signals received from a set of GPS or GNSS satellites and/or one or more falsified signals, such as spoofer signals (falsified). The processor is configured to determine, based on an expected location of a respective GPS or GNSS satellite of the set of GPS or GNSS satellites, an expected gain or expected power for a respective signal of the signals. The GPS or GNSS receiver is configured to measure a power of the respective signal, compare the measured power to the expected gain or expected power, and determine whether the respective signal is falsified based on the comparison.

Inventors

  • WEGER, JOHN J.

Assignees

  • BAE SYSTEMS Information and Electronic Systems Integration Inc.

Dates

Publication Date
20260506
Application Date
20240530

Claims (20)

  1. 1. A Global Positioning System (GPS) or global navigation satellite system (GNSS) comprising at least: antenna electronics configured to provide signals to a GPS or GNSS receiver, wherein the signals comprise GPS or GNSS satellite signals received from a set of GPS or GNSS satellites and/or one or more falsified signals; a digital signal processor (DSP) configured to determine, based on an expected location of a respective GPS or GNSS satellite of the set of GPS or GNSS satellites, an expected gain or expected power for a respective signal of the signals; and the GPS or GNSS receiver, wherein the GPS or GNSS receiver is configured to measure a power of the respective signal, compare the measured power to the expected gain or expected power, and determine whether the respective signal is falsified based on the comparison.
  2. 2. The GPS or GNSS of claim 1, wherein to provide the signals comprises to provide a set of antenna beams formed based on the signals, the expected gain or expected power for the respective signal is based on an expected gain for a respective antenna beam of the set of antenna beams at the expected location of the respective GPS or GNSS satellite, the respective antenna beam is steered to a respective steering location, and the measured power of the respective signal comprises a measured power of the respective signal while the respective signal is tracked on the respective antenna beam.
  3. 3. The GPS or GNSS of claim 2, wherein the GPS or GNSS receiver is further configured to track the respective signal on the set of antenna beams.
  4. 4. The GPS or GNSS of claim 2, wherein the GPS or GNSS receiver is further configured to rank the expected gain or expected power relative to a second expected gain or second expected power for a second antenna beam, and rank the measured power relative to a second measured power for the second antenna beam, and to compare the measured power to the expected gain or expected power is based on the rankings.
  5. 5. The GPS or GNSS of claim 1, wherein to determine whether the respective signal is falsified based on the comparison further comprises to determine whether the respective signal is falsified based on a change over time in one or more of: the expected location of the respective GPS or GNSS satellite, an attitude or orientation of a GPS or GNSS antenna array, or a disparity in expected gain among the signals on an antenna beam.
  6. 6. The GPS or GNSS of claim 1, wherein to determine the expected gain or expected power for the respective signal is based on a set of weights.
  7. 7. The GPS or GNSS of claim 6, further comprising adder and/or multiplier circuitry configured to compute a covariance matrix specifying spatial cross-correlations of antenna elements, and wherein the set of weights is based on an inverse of the covariance matrix, and a beam constraint matrix.
  8. 8. The GPS or GNSS of claim 1, wherein: the respective signal is authentic and originates from the respective GPS or GNSS satellite; or the respective signal is falsified and originates from one or more of a satellite spoofer, an aircraft spoofer, a drone spoofer, a maritime spoofer, or a land based spoofer.
  9. 9. A Global Positioning System (GPS) or global navigation satellite system (GNSS) method, comprising: providing, by antenna electronics and to a GPS or GNSS receiver, signals, wherein the signals comprise GPS or GNSS satellite signals received from a set of GPS or GNSS satellites and/or one or more falsified signals; determining, by a digital signal processor (DSP) and based on an expected location of a respective GPS or GNSS satellite of the set of GPS or GNSS satellites, an expected gain or expected power for a respective signal of the signals; measuring, by the GPS or GNSS receiver, a power of the respective signal; comparing the measured power to the expected gain or expected power; and determining whether the respective signal is falsified based on the comparison.
  10. 10. The GPS or GNSS method of claim 9, wherein providing the signals comprises forming a set of antenna beams based on the signals, determining the expected gain or expected power for the respective signal comprises determining an expected gain or expected power for a respective antenna beam of the set of antenna beams at the expected location of the respective GPS or GNSS satellite, the respective antenna beam is steered to a respective steering location, and measuring the power for the respective signal comprises measuring the power for the respective signal while the respective signal is tracked on the respective antenna beam.
  11. 11. The GPS or GNSS method of claim 10, further comprising tracking, by the GPS or GNSS receiver, the respective signal on the set of antenna beams.
  12. 12. The GPS or GNSS method of claim 10, further comprising ranking the expected gain or expected power relative to a second expected gain or second expected power for a second antenna beam, and ranking the measured power relative to a second measured power for the second antenna beam, and wherein comparing the measured power to the expected gain or expected power is based on the rankings.
  13. 13. The GPS or GNSS method of claim 9, wherein determining whether the respective signal is falsified based on the comparison further comprises determining whether the respective signal is falsified based on a change over time in one or more of: the expected location of the respective GPS or GNSS satellite, an attitude or orientation of a GPS or GNSS antenna array, or a disparity in expected gain among the signals on an antenna beam.
  14. 14. The GPS or GNSS method of claim 9, wherein determining the expected gain or expected power for the respective signal is based on a set of weights.
  15. 15. The GPS or GNSS method of claim 14, further comprising computing, by adder and/or multiplier circuitry, a covariance matrix specifying spatial cross-correlations of antenna elements, and wherein the set of weights is based on an inverse of the covariance matrix, and a beam constraint matrix.
  16. 16. A system, comprising a Global Positioning System (GPS) or global navigation satellite system (GNSS) antenna array configured to receive signals, wherein the signals comprise GPS or GNSS satellite signals received from a set of GPS or GNSS satellites and/or one or more falsified signals; antenna electronics configured to provide the signals comprising the GPS or GNSS satellite signals to a GPS or GNSS receiver, and a GPS or GNSS digital signal processor (DSP) configured to determine, based on an expected location of a respective GPS or GNSS satellite of the set of GPS or GNSS satellites, an expected gain or expected power for a respective signal of the signals; and the GPS or GNSS receiver, wherein the GPS or GNSS receiver is configured to: measure a power of the respective signal; compare the expected gain or expected power to the measured power; and determine whether the respective signal is falsified based on the comparison.
  17. 17. The system of claim 16, wherein to provide the signals to the receiver further comprises to form a set of antenna beams based on the signals received by the antenna array, the expected gain or expected power for the respective signal is based on an expected gain for a respective antenna beam of the set of antenna beams at the expected location of the respective GPS or GNSS satellite, the antenna electronics are further configured to steer the respective antenna beam to a respective steering location, and the measured power of the respective signal comprises a measured power of the respective signal while the respective signal is tracked on the respective antenna beam.
  18. 18. The system of claim 17, wherein the GPS or GNSS receiver is further configured to rank the expected gain or expected power relative to a second expected gain or second expected power for a second antenna beam, and rank the measured power relative to a second measured power for the second antenna beam, and to compare the measured power to the expected gain or expected power is based on the rankings.
  19. 19. The system of claim 16, wherein to determine whether the respective signal is falsified based on the comparison comprises to determine whether the respective signal is falsified based on a change over time in one or more of: the expected location of the respective GPS or GNSS satellite, an attitude or orientation of the GPS or GNSS antenna array, or a disparity in expected gain among the signals on an antenna beam.
  20. 20. The system of claim 16, wherein to determine the expected gain or expected power for the respective signal is based on a set of weights.

Description

GPS SATELLITE SIGNAL AUTHENTICATION BASED ON RELATIVE GAIN USING BEAMFORMING ANTENNA ELECTRONICS BACKGROUND [0001] An important aspect of Global Positioning System (GPS) and global navigation satellite system (GNSS) technology is assurance of the accuracy and integrity of GPS and/or GNSS navigation data and timing. For example, assuring navigation data and timing in support of aerospace systems can be especially important in order to mitigate threats, such as adversarial spoofing or jamming signals. For instance, spoofed or falsified GPS or GNSS signals can imitate authentic signals, so as to confuse a GPS or GNSS system and users into misidentifying the source of a signal and/or mistaking a GPS or GNSS location. There is a need for techniques to detect spoofed signals and provide confidence that signals are authentic. SUMMARY [0002] In an example, a Global Positioning System (GPS) or global navigation satellite system (GNSS) device comprising at least antenna electronics, a digital signal processor (DSP), and a GPS or GNSS receiver is provided. The antenna electronics can be configured to provide signals received from one or more sources to the GPS or GNSS receiver. In some cases, the signals may comprise one or more GPS or GNSS satellite signals, and the one or more sources may comprise a set of GPS or GNSS satellites. In some cases, the signals comprise one or more falsified signals, and the one or more sources may comprise one or more spoofer source (e.g., a satellite spoofer, an aircraft spoofer, a drone spoofer, a maritime spoofer, or a land based spoofer). Accordingly, in some cases, the GPS or GNSS receiver can be configured to determine whether the signals comprise a falsified signal or the one or more sources comprise a spoofer source, as disclosed herein. The DSP can be configured to determine, based on an expected location of a respective GPS or GNSS satellite of the set of GPS or GNSS satellites, an expected gain or expected power for a respective signal of the signals. In some cases, the DSP can also determine an antenna gain pattern as manipulated by the antenna electronics, and/or can determine the expected gain or expected power together with the antenna gain pattern. The GPS or GNSS receiver can be configured to receive the signals from the antenna electronics, and measure a power of the respective signal. The receiver can be further configured to compare the measured power to the expected gain or expected power, and determine whether the respective signal is falsified based on the comparison. For example, the receiver may determine the respective signal is authentic and likely originates from the respective GPS or GNSS satellite. Alternatively, the receiver may determine the respective signal is falsified and likely originates from a spoofer source (such as a satellite spoofer, an aircraft spoofer, a drone spoofer, a maritime spoofer, or a land based spoofer). [0003] In another example, a Global Positioning System (GPS) or global navigation satellite system (GNSS) method is provided. The method can comprise providing, by antenna electronics and to a GPS or GNSS receiver, signals received from one or more sources. In some cases, the signals may comprise one or more GPS or GNSS satellite signals, and the one or more sources may comprise a set of GPS or GNSS satellites. In some cases, the signals comprise one or more falsified signals, and the one or more sources may comprise one or more spoofer source (e.g., a satellite spoofer, an aircraft spoofer, a drone spoofer, a maritime spoofer, or a land based spoofer). Accordingly, in some cases, the GPS or GNSS receiver can be configured to determine whether the signals comprise a falsified signal or the one or more sources comprise a spoofer source, as disclosed herein. The method can further comprise determining, by a digital signal processor (DSP) and based on an expected location of a respective GPS or GNSS satellite of the set of GPS or GNSS satellites, an expected gain or expected power for a respective signal of the signals. In some cases, the method can further comprise determining, by the DSP, an antenna gain pattern as manipulated by the antenna electronics, and/or determining the expected gain or expected power together with the antenna gain pattern. The method can further comprise measuring, by the GPS or GNSS receiver, a power of the respective signal. The method can further comprise comparing the expected gain or expected power to the measured power. The method can further comprise determining whether the respective signal is falsified based on the comparison. For example, the method may determine the respective signal is authentic and likely originates from the respective GPS or GNSS satellite. Alternatively, the method may determine the respective signal is falsified and likely originates from a spoofer source (such as a satellite spoofer, an aircraft spoofer, a drone spoofer, a maritime spoofer, or a land based spoofer). [0004]