GPS Spoofing Detection via ADS-B and TCAS Distance Comparison
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Solution Overview
Problem
Existing methods for detecting GPS spoofing in vehicles, such as satellite signal encryption and statistical tests, are costly or prone to false alarms and missed detections, and rely on data not always available at GPS receiver outputs.
Innovation Solution
A method and apparatus utilizing Automatic Dependent Surveillance-Broadcast (ADS-B) and Traffic Alert and Collision Avoidance System (TCAS) to verify GPS signal accuracy by comparing calculated distances between vehicles, generating indicators of potential GPS spoofing based on threshold comparisons, and using a ranking equation to determine relative probabilities of spoofing among vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If satellite signal encryption/authentication is used for GPS spoofing detection, then detection reliability is improved, but system cost and complexity increase significantly
Solution Approach 1:
The patent introduces an intermediary verification mechanism using independent position sensors (IRS, DME/DME, DME/VOR) as mediators to cross-check GPS position data. Instead of directly encrypting/authenticating GPS signals, the system uses these intermediary sensors to verify position accuracy, thereby improving detection reliability without requiring complex signal encryption infrastructure.
Solution Approach 2:
The patent replaces the mechanical/electronic signal encryption system with a computational verification approach. Instead of modifying the physical GPS signal transmission through encryption, the system substitutes a software-based cross-validation process that compares GPS-derived position with positions from other sensors, achieving the same security goal with simpler infrastructure.
2Measurement precision
If statistical tests of GPS signal measurements are used for spoofing detection, then detection capability is improved, but false alarms and missed detections increase due to signal variation and multipath environments
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors multiple independent position sensors and compares their readings. When discrepancies exceed thresholds, the system generates alerts and can switch to alternative positioning sources. This closed-loop feedback approach corrects for signal variations and multipath effects by constantly validating against other measurement sources, reducing false alarms while maintaining detection precision.
3Measurement precision
If position consistency check with other position sensors is used for GPS spoofing detection, then detection accuracy is improved, but system reliability decreases due to inherent IRS drift and unavailable radio position data
Solution Approach 1:
The patent prepares for sensor failures and drift by implementing redundant positioning systems and pre-established fallback procedures. The system continuously monitors the health and accuracy of each sensor source, maintaining ready backup methods. When IRS drift or radio position unavailability occurs, the system has pre-planned alternative verification paths, cushioning against reliability degradation from individual sensor failures.
Data Source
AI summary
A method of indicating whether a GPS signal received by a vehicle is accurate includes obtaining the GPS signal and calculating position information of the vehicle based on the GPS signal. The method further includes obtaining position information of another vehicle via a broadcast. The method further includes calculating a first distance information to the other vehicle based on the position information of the other vehicle and the position information of the vehicle. The method further includes obtaining a second distance information to the other vehicle via a collision avoidance system on the vehicle. The method further includes comparing the first distance information to the second distance information, and generating an indicator that the vehicle and the other vehicle may have received an inaccurate GPS signal when a result of the comparison is higher than a threshold.