GNSS Signal Authentication via Antenna Radiation Pattern Control

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Solution Overview

Problem

Existing GNSS signal authentication methods are inadequate for ensuring the integrity of navigation signals, particularly in critical applications like aircraft terrain collision avoidance systems, and are not suitable for mass market receivers due to their complexity and computational requirements, limiting their use in semi-critical applications such as land transport and electronic payments.

Innovation Solution

A compact GNSS signal anti-spoofing system that remotely and securely checks the radiation pattern of the receiver's antenna using pseudo-random code-generated control sequences, PVT data, and encryption, allowing for the production of an authentication certificate only if consistency tests are met, and distributing algorithmic processing across different processors to accommodate standard smartphone capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical antenna diversity generation devices are used to authenticate GNSS signals, then signal authentication capability is improved, but device complexity and computational requirements increase significantly

Engineering Contradiction:
Improvesignal authentication capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical antenna diversity generation devices with an electronic control system that uses a processor to generate control sequences for electronically adjusting antenna radiation patterns. This substitution eliminates the need for complex mechanical movements while achieving the same authentication function through electronic signal processing and control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state of the antenna system by electronically controlling radiation pattern parameters (directionality, coverage area) through software-generated control sequences. This allows dynamic adjustment of antenna characteristics without mechanical movement, reducing device complexity while maintaining authentication capability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If mechanical antenna diversity generation devices are used to authenticate GNSS signals, then signal authentication capability is improved, but ease of operation and integration with mass market receivers deteriorates

Engineering Contradiction:
Improvesignal authentication capabilityVSAvoidease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces complex mechanical antenna diversity devices with an electronic control system that can be integrated into standard receiver hardware. The processor generates control sequences that electronically adjust antenna radiation patterns, eliminating mechanical complexity and making the system suitable for mass market receivers like smartphones.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a universal authentication mechanism that can be integrated into various receiver types (mobile phones, vehicles, fixed stations) using the same electronic control principle. This multi-functional approach allows the same technology to serve different applications without requiring device-specific mechanical implementations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If conventional anti-spoofing methods using external reference information are used, then authentication is simplified, but reliability is insufficient for critical applications requiring integrity of all system components

Engineering Contradiction:
Improveauthentication method simplicityVSAvoidauthentication reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent enables the receiver to authenticate signals using its own antenna radiation pattern characteristics rather than relying on external reference information. The system self-verifies signal authenticity by comparing received signal properties against the known radiation pattern of its antenna, providing intrinsic authentication that doesn't depend on external systems or references.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent performs preliminary characterization of the antenna radiation pattern and stores this information for later authentication use. By pre-establishing the expected radiation pattern properties, the system can subsequently verify signal authenticity without requiring complex real-time external references, balancing simplicity with reliability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3189350B1Method for authenticating signals received from a constellation of satellites
Publication Date: 2021.11.03 CENT NAT DETUD SPATIALES (CNES)
  • EP3189350B1 patent drawingFigure 1a~1b
  • EP3189350B1 patent drawingFigure 2
  • EP3189350B1 patent drawingFigure 3

AI summary

The positioning signals broadcast by the GNSS constellations on civilian frequencies are likely to be counterfeited, while the use of authentic signals is becoming increasingly critical for certain applications. According to the invention, the authentication of GNSS signals is performed by analysis of consistency between the measurements of parameters characteristic of the signals (direction of arrival, amplitude, phase) and their state model, said state model taking account of an emulation by software and electronic means of displacements of the phase centre of the antenna and/or of the main lobe of the radiation pattern. Advantageously, these displacements are generated by a pseudo-random code. Advantageously, the analysis of consistency between measurements and models is a multiple-criterion analysis, the combination of criteria being chosen as a function of a reception quality indicator and/or of a presumed location.