GNSS Anti-Spoofing via Multi-Element Antenna Angle Analysis
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Solution Overview
Problem
Global navigation satellite systems (GNSS) are vulnerable to spoofing attacks, where fake signals with incorrect position or time information are transmitted, disrupting the receiver's ability to determine its position accurately, and existing anti-spoofing systems relying on signal strength comparisons are not always effective, especially in targeted or weak signal scenarios.
Innovation Solution
A method and system using a multi-element antenna to determine the angle of arrival for received navigation signals, analyzing these angles to identify spoofed signals, and suppressing them by comparing with expected angles based on satellite positions and signal strength, allowing legitimate signals to be used for position calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If signal strength comparison is used for anti-spoofing, then implementation is simple, but effectiveness is insufficient in targeted or weak signal scenarios
Solution Approach 1:
The patent transitions from one-dimensional signal strength comparison to two-dimensional analysis by incorporating angle of arrival (AOA) information. The system now evaluates both signal strength and spatial direction, creating a more comprehensive authentication mechanism that effectively detects spoofed signals attempting to masquerade as legitimate GNSS satellites from specific directions.
Solution Approach 2:
The patent divides the anti-spoofing verification into separate functional components: signal strength evaluation and angle of arrival analysis. This segmentation allows independent optimization of each verification dimension and enables the system to detect spoofing attempts that succeed in one dimension but fail in another.
2Measurement precision
If multi-element antenna with angle of arrival analysis is used, then spoofing detection accuracy is improved, but device complexity increases
Solution Approach 1:
The multi-element antenna array serves multiple functions simultaneously: it receives GNSS signals for navigation, determines angles of arrival for spoofing detection, and provides spatial filtering capabilities. This multi-functionality justifies the increased complexity by delivering multiple verification capabilities through a single hardware component.
Solution Approach 2:
The patent employs signal copying and comparison techniques where the received signal characteristics (angle and strength) are copied and compared against expected values for legitimate satellites. This copying approach enables precise verification without requiring complex real-time computation of satellite positions and signal propagation models.
3Reliability
If angle of arrival analysis is performed for all received signals, then spoofed signals are effectively identified, but processing time increases
Solution Approach 1:
The patent applies partial verification by first checking signal strength thresholds and only performing full angle of arrival analysis on signals that pass the initial strength filter. This partial action approach quickly rejects obviously spoofed signals with excessive strength while reserving computationally intensive AOA analysis for potentially legitimate signals, thereby reducing overall processing time.
Solution Approach 2:
The system performs preliminary signal strength evaluation before conducting angle of arrival analysis. This preliminary action filters out obviously spoofed signals early in the processing chain, reducing the number of signals requiring full verification and thus decreasing total processing time while maintaining high authentication reliability.
Data Source
AI summary
A system for identifying spoofed navigation signals includes a multi-element antenna configured to receive a plurality of navigation signals. The system also includes at least one processor configured to determine an angle of arrival for each of the navigation signals and analyze the angles of arrival for the navigation signals to determine whether one or more of the navigation signals are spoofed. To analyze the angles of arrival for the navigation signals, the at least one processor may be configured to (i) determine whether two or more of the navigation signals were received at substantially the same angle of arrival (which may be based on a difference of less than 5° between the angles of arrival) and/or (ii) compare the angles of arrival for the navigation signals to at least one expected angle of arrival (which may be based on information about expected or actual positions of multiple satellites).