GNSS Interference Detection via Surveillance Message Discrepancy
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Solution Overview
Problem
Global Navigation Satellite System (GNSS) devices in vehicles are susceptible to unintentional interference and intentional spoofing, leading to incorrect position determinations, which can cause false alarms in terrain awareness and collision avoidance systems.
Innovation Solution
A system that detects GNSS interference by analyzing surveillance messages for discrepancies using position filters, time validations, and range validations, determining if a threshold percentage of vehicles report positions that differ significantly from predicted positions, thereby identifying interfered or spoofed signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS signals are used for position determination, then vehicle positioning capability is improved, but susceptibility to interference and spoofing increases
Solution Approach 1:
The patent introduces surveillance messages as an intermediary verification mechanism. Instead of directly trusting GNSS position data, the system uses surveillance messages from multiple vehicles to cross-check and validate position information. This intermediary layer detects discrepancies caused by interference or spoofing without eliminating the useful GNSS positioning function.
Solution Approach 2:
The system implements feedback by continuously monitoring surveillance messages and comparing reported positions with predicted positions. When discrepancies exceed thresholds, the system generates alerts and can suppress false alarms in terrain awareness and collision avoidance systems. This closed-loop feedback mechanism dynamically adjusts system behavior based on detected interference conditions.
2Measurement precision
If surveillance messages are analyzed from multiple vehicles, then detection accuracy of GNSS interference is improved, but system complexity increases
Solution Approach 1:
The patent segments the interference detection function into modular components: position filtering, time validation, range validation, and discrepancy analysis. Each component handles a specific aspect of verification, making the overall complex system manageable through functional segmentation. This modular approach allows independent optimization and troubleshooting of each validation stage.
Solution Approach 2:
The surveillance message analysis system serves multiple functions simultaneously: it validates GNSS positioning, detects interference, provides feedback for alarm suppression, and enables collaborative verification across multiple vehicles. This multi-functionality reduces the need for separate dedicated systems for each function, thereby managing complexity while achieving comprehensive interference detection.
3Reliability
If position filtering and validation tests are performed, then false alarm reduction is improved, but processing time increases
Solution Approach 1:
The system performs preliminary position filtering and validation tests on surveillance messages before they are used for critical decisions. By pre-validating position data through filtering and discrepancy checks, the system reduces the computational burden during critical alarm evaluation, thereby reducing actual processing time for safety-critical functions while maintaining high reliability.
Data Source
AI summary
In some examples, a system includes a transceiver configured to receive surveillance messages from Y target vehicles, where Y is an integer greater than two. The system includes processing circuitry configured to determine predicted positions of the Y target vehicles based on the surveillance messages. The processing circuitry is also configured to determine reported positions of the Y target vehicles based on later received surveillance messages. The processing circuitry is further configured to determine that respective differences between the respective predicted position and the respective reported position for X of the Y target vehicles is greater than a threshold distance. The processing circuitry is configured to determine that Global Navigation Satellite System interference has occurred in response to determining that X divided by Y is greater than a threshold level.